/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim:set ts=2 sw=2 sts=2 et cindent: */ /* ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1 * * The contents of this file are subject to the Mozilla Public License Version * 1.1 (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the * License. * * The Original Code is Mozilla code. * * The Initial Developer of the Original Code is the Mozilla Corporation. * Portions created by the Initial Developer are Copyright (C) 2007 * the Initial Developer. All Rights Reserved. * * Contributor(s): * Chris Double * Chris Pearce * * Alternatively, the contents of this file may be used under the terms of * either the GNU General Public License Version 2 or later (the "GPL"), or * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */ #include "nsError.h" #include "nsBuiltinDecoderStateMachine.h" #include "nsBuiltinDecoder.h" #include "nsOggReader.h" #include "VideoUtils.h" #include "theora/theoradec.h" #include "nsTimeRanges.h" #include "mozilla/TimeStamp.h" using namespace mozilla; // Un-comment to enable logging of seek bisections. //#define SEEK_LOGGING #ifdef PR_LOGGING extern PRLogModuleInfo* gBuiltinDecoderLog; #define LOG(type, msg) PR_LOG(gBuiltinDecoderLog, type, msg) #ifdef SEEK_LOGGING #define SEEK_LOG(type, msg) PR_LOG(gBuiltinDecoderLog, type, msg) #else #define SEEK_LOG(type, msg) #endif #else #define LOG(type, msg) #define SEEK_LOG(type, msg) #endif // The number of microseconds of "fuzz" we use in a bisection search over // HTTP. When we're seeking with fuzz, we'll stop the search if a bisection // lands between the seek target and SEEK_FUZZ_USECS microseconds before the // seek target. This is becaue it's usually quicker to just keep downloading // from an exisiting connection than to do another bisection inside that // small range, which would open a new HTTP connetion. static const PRUint32 SEEK_FUZZ_USECS = 500000; enum PageSyncResult { PAGE_SYNC_ERROR = 1, PAGE_SYNC_END_OF_RANGE= 2, PAGE_SYNC_OK = 3 }; // Reads a page from the media stream. static PageSyncResult PageSync(nsMediaStream* aStream, ogg_sync_state* aState, bool aCachedDataOnly, PRInt64 aOffset, PRInt64 aEndOffset, ogg_page* aPage, int& aSkippedBytes); // Chunk size to read when reading Ogg files. Average Ogg page length // is about 4300 bytes, so we read the file in chunks larger than that. static const int PAGE_STEP = 8192; class nsAutoReleasePacket { public: nsAutoReleasePacket(ogg_packet* aPacket) : mPacket(aPacket) { } ~nsAutoReleasePacket() { nsOggCodecState::ReleasePacket(mPacket); } private: ogg_packet* mPacket; }; nsOggReader::nsOggReader(nsBuiltinDecoder* aDecoder) : nsBuiltinDecoderReader(aDecoder), mTheoraState(nsnull), mVorbisState(nsnull), mSkeletonState(nsnull), mVorbisSerial(0), mTheoraSerial(0), mPageOffset(0) { MOZ_COUNT_CTOR(nsOggReader); memset(&mTheoraInfo, 0, sizeof(mTheoraInfo)); } nsOggReader::~nsOggReader() { ogg_sync_clear(&mOggState); MOZ_COUNT_DTOR(nsOggReader); } nsresult nsOggReader::Init(nsBuiltinDecoderReader* aCloneDonor) { bool init = mCodecStates.Init(); NS_ASSERTION(init, "Failed to initialize mCodecStates"); if (!init) { return NS_ERROR_FAILURE; } int ret = ogg_sync_init(&mOggState); NS_ENSURE_TRUE(ret == 0, NS_ERROR_FAILURE); return NS_OK; } nsresult nsOggReader::ResetDecode() { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); nsresult res = NS_OK; if (NS_FAILED(nsBuiltinDecoderReader::ResetDecode())) { res = NS_ERROR_FAILURE; } // Discard any previously buffered packets/pages. ogg_sync_reset(&mOggState); if (mVorbisState && NS_FAILED(mVorbisState->Reset())) { res = NS_ERROR_FAILURE; } if (mTheoraState && NS_FAILED(mTheoraState->Reset())) { res = NS_ERROR_FAILURE; } return res; } bool nsOggReader::ReadHeaders(nsOggCodecState* aState) { while (!aState->DoneReadingHeaders()) { ogg_packet* packet = NextOggPacket(aState); nsAutoReleasePacket autoRelease(packet); if (!packet || !aState->IsHeader(packet)) { aState->Deactivate(); } else { aState->DecodeHeader(packet); } } return aState->Init(); } nsresult nsOggReader::ReadMetadata(nsVideoInfo* aInfo) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); // We read packets until all bitstreams have read all their header packets. // We record the offset of the first non-header page so that we know // what page to seek to when seeking to the media start. ogg_page page; nsAutoTArray bitstreams; bool readAllBOS = false; while (!readAllBOS) { PRInt64 pageOffset = ReadOggPage(&page); if (pageOffset == -1) { // Some kind of error... break; } int serial = ogg_page_serialno(&page); nsOggCodecState* codecState = 0; if (!ogg_page_bos(&page)) { // We've encountered a non Beginning Of Stream page. No more BOS pages // can follow in this Ogg segment, so there will be no other bitstreams // in the Ogg (unless it's invalid). readAllBOS = true; } else if (!mCodecStates.Get(serial, nsnull)) { // We've not encountered a stream with this serial number before. Create // an nsOggCodecState to demux it, and map that to the nsOggCodecState // in mCodecStates. codecState = nsOggCodecState::Create(&page); DebugOnly r = mCodecStates.Put(serial, codecState); NS_ASSERTION(r, "Failed to insert into mCodecStates"); bitstreams.AppendElement(codecState); mKnownStreams.AppendElement(serial); if (codecState && codecState->GetType() == nsOggCodecState::TYPE_VORBIS && !mVorbisState) { // First Vorbis bitstream, we'll play this one. Subsequent Vorbis // bitstreams will be ignored. mVorbisState = static_cast(codecState); } if (codecState && codecState->GetType() == nsOggCodecState::TYPE_THEORA && !mTheoraState) { // First Theora bitstream, we'll play this one. Subsequent Theora // bitstreams will be ignored. mTheoraState = static_cast(codecState); } if (codecState && codecState->GetType() == nsOggCodecState::TYPE_SKELETON && !mSkeletonState) { mSkeletonState = static_cast(codecState); } } mCodecStates.Get(serial, &codecState); NS_ENSURE_TRUE(codecState, NS_ERROR_FAILURE); if (NS_FAILED(codecState->PageIn(&page))) { return NS_ERROR_FAILURE; } } // We've read all BOS pages, so we know the streams contained in the media. // Now process all available header packets in the active Theora, Vorbis and // Skeleton streams. // Deactivate any non-primary bitstreams. for (PRUint32 i = 0; i < bitstreams.Length(); i++) { nsOggCodecState* s = bitstreams[i]; if (s != mVorbisState && s != mTheoraState && s != mSkeletonState) { s->Deactivate(); } } if (mTheoraState && ReadHeaders(mTheoraState)) { nsIntRect picture = nsIntRect(mTheoraState->mInfo.pic_x, mTheoraState->mInfo.pic_y, mTheoraState->mInfo.pic_width, mTheoraState->mInfo.pic_height); nsIntSize displaySize = nsIntSize(mTheoraState->mInfo.pic_width, mTheoraState->mInfo.pic_height); // Apply the aspect ratio to produce the intrinsic display size we report // to the element. ScaleDisplayByAspectRatio(displaySize, mTheoraState->mPixelAspectRatio); nsIntSize frameSize(mTheoraState->mInfo.frame_width, mTheoraState->mInfo.frame_height); if (nsVideoInfo::ValidateVideoRegion(frameSize, picture, displaySize)) { // Video track's frame sizes will not overflow. Activate the video track. mInfo.mHasVideo = true; mInfo.mDisplay = displaySize; mPicture = picture; mDecoder->SetVideoData(gfxIntSize(displaySize.width, displaySize.height), nsnull, TimeStamp::Now()); // Copy Theora info data for time computations on other threads. memcpy(&mTheoraInfo, &mTheoraState->mInfo, sizeof(mTheoraInfo)); mTheoraSerial = mTheoraState->mSerial; } } if (mVorbisState && ReadHeaders(mVorbisState)) { mInfo.mHasAudio = true; mInfo.mAudioRate = mVorbisState->mInfo.rate; mInfo.mAudioChannels = mVorbisState->mInfo.channels; // Copy Vorbis info data for time computations on other threads. memcpy(&mVorbisInfo, &mVorbisState->mInfo, sizeof(mVorbisInfo)); mVorbisInfo.codec_setup = NULL; mVorbisSerial = mVorbisState->mSerial; } else { memset(&mVorbisInfo, 0, sizeof(mVorbisInfo)); } if (mSkeletonState) { if (!HasAudio() && !HasVideo()) { // We have a skeleton track, but no audio or video, may as well disable // the skeleton, we can't do anything useful with this media. mSkeletonState->Deactivate(); } else if (ReadHeaders(mSkeletonState) && mSkeletonState->HasIndex()) { // Extract the duration info out of the index, so we don't need to seek to // the end of stream to get it. nsAutoTArray tracks; if (HasVideo()) { tracks.AppendElement(mTheoraState->mSerial); } if (HasAudio()) { tracks.AppendElement(mVorbisState->mSerial); } PRInt64 duration = 0; if (NS_SUCCEEDED(mSkeletonState->GetDuration(tracks, duration))) { ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor()); mDecoder->GetStateMachine()->SetDuration(duration); LOG(PR_LOG_DEBUG, ("Got duration from Skeleton index %lld", duration)); } } } { ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor()); nsMediaStream* stream = mDecoder->GetStream(); if (mDecoder->GetStateMachine()->GetDuration() == -1 && mDecoder->GetStateMachine()->GetState() != nsDecoderStateMachine::DECODER_STATE_SHUTDOWN && stream->GetLength() >= 0 && mDecoder->GetStateMachine()->IsSeekable()) { // We didn't get a duration from the index or a Content-Duration header. // Seek to the end of file to find the end time. PRInt64 length = stream->GetLength(); NS_ASSERTION(length > 0, "Must have a content length to get end time"); PRInt64 endTime = 0; { ReentrantMonitorAutoExit exitMon(mDecoder->GetReentrantMonitor()); endTime = RangeEndTime(length); } if (endTime != -1) { mDecoder->GetStateMachine()->SetEndTime(endTime); LOG(PR_LOG_DEBUG, ("Got Ogg duration from seeking to end %lld", endTime)); } } } *aInfo = mInfo; return NS_OK; } nsresult nsOggReader::DecodeVorbis(ogg_packet* aPacket) { NS_ASSERTION(aPacket->granulepos != -1, "Must know vorbis granulepos!"); if (vorbis_synthesis(&mVorbisState->mBlock, aPacket) != 0) { return NS_ERROR_FAILURE; } if (vorbis_synthesis_blockin(&mVorbisState->mDsp, &mVorbisState->mBlock) != 0) { return NS_ERROR_FAILURE; } VorbisPCMValue** pcm = 0; PRInt32 frames = 0; PRUint32 channels = mVorbisState->mInfo.channels; ogg_int64_t endFrame = aPacket->granulepos; while ((frames = vorbis_synthesis_pcmout(&mVorbisState->mDsp, &pcm)) > 0) { mVorbisState->ValidateVorbisPacketSamples(aPacket, frames); nsAutoArrayPtr buffer(new AudioDataValue[frames * channels]); for (PRUint32 j = 0; j < channels; ++j) { VorbisPCMValue* channel = pcm[j]; for (PRUint32 i = 0; i < PRUint32(frames); ++i) { buffer[i*channels + j] = MOZ_CONVERT_VORBIS_SAMPLE(channel[i]); } } PRInt64 duration = mVorbisState->Time((PRInt64)frames); PRInt64 startTime = mVorbisState->Time(endFrame - frames); mAudioQueue.Push(new AudioData(mPageOffset, startTime, duration, frames, buffer.forget(), channels)); endFrame -= frames; if (vorbis_synthesis_read(&mVorbisState->mDsp, frames) != 0) { return NS_ERROR_FAILURE; } } return NS_OK; } bool nsOggReader::DecodeAudioData() { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); NS_ASSERTION(mVorbisState!=0, "Need Vorbis state to decode audio"); // Read the next data packet. Skip any non-data packets we encounter. ogg_packet* packet = 0; do { if (packet) { nsOggCodecState::ReleasePacket(packet); } packet = NextOggPacket(mVorbisState); } while (packet && mVorbisState->IsHeader(packet)); if (!packet) { mAudioQueue.Finish(); return false; } NS_ASSERTION(packet && packet->granulepos != -1, "Must have packet with known granulepos"); nsAutoReleasePacket autoRelease(packet); DecodeVorbis(packet); if (packet->e_o_s) { // We've encountered an end of bitstream packet, or we've hit the end of // file while trying to decode, so inform the audio queue that there'll // be no more samples. mAudioQueue.Finish(); return false; } return true; } nsresult nsOggReader::DecodeTheora(ogg_packet* aPacket, PRInt64 aTimeThreshold) { NS_ASSERTION(aPacket->granulepos >= TheoraVersion(&mTheoraState->mInfo,3,2,1), "Packets must have valid granulepos and packetno"); int ret = th_decode_packetin(mTheoraState->mCtx, aPacket, 0); if (ret != 0 && ret != TH_DUPFRAME) { return NS_ERROR_FAILURE; } PRInt64 time = mTheoraState->StartTime(aPacket->granulepos); // Don't use the frame if it's outside the bounds of the presentation // start time in the skeleton track. Note we still must submit the frame // to the decoder (via th_decode_packetin), as the frames which are // presentable may depend on this frame's data. if (mSkeletonState && !mSkeletonState->IsPresentable(time)) { return NS_OK; } PRInt64 endTime = mTheoraState->Time(aPacket->granulepos); if (endTime < aTimeThreshold) { // The end time of this frame is already before the current playback // position. It will never be displayed, don't bother enqueing it. return NS_OK; } if (ret == TH_DUPFRAME) { VideoData* v = VideoData::CreateDuplicate(mPageOffset, time, endTime, aPacket->granulepos); mVideoQueue.Push(v); } else if (ret == 0) { th_ycbcr_buffer buffer; ret = th_decode_ycbcr_out(mTheoraState->mCtx, buffer); NS_ASSERTION(ret == 0, "th_decode_ycbcr_out failed"); bool isKeyframe = th_packet_iskeyframe(aPacket) == 1; VideoData::YCbCrBuffer b; for (PRUint32 i=0; i < 3; ++i) { b.mPlanes[i].mData = buffer[i].data; b.mPlanes[i].mHeight = buffer[i].height; b.mPlanes[i].mWidth = buffer[i].width; b.mPlanes[i].mStride = buffer[i].stride; } VideoData *v = VideoData::Create(mInfo, mDecoder->GetImageContainer(), mPageOffset, time, endTime, b, isKeyframe, aPacket->granulepos, mPicture); if (!v) { // There may be other reasons for this error, but for // simplicity just assume the worst case: out of memory. NS_WARNING("Failed to allocate memory for video frame"); return NS_ERROR_OUT_OF_MEMORY; } mVideoQueue.Push(v); } return NS_OK; } bool nsOggReader::DecodeVideoFrame(bool &aKeyframeSkip, PRInt64 aTimeThreshold) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); // Record number of frames decoded and parsed. Automatically update the // stats counters using the AutoNotifyDecoded stack-based class. PRUint32 parsed = 0, decoded = 0; nsMediaDecoder::AutoNotifyDecoded autoNotify(mDecoder, parsed, decoded); // Read the next data packet. Skip any non-data packets we encounter. ogg_packet* packet = 0; do { if (packet) { nsOggCodecState::ReleasePacket(packet); } packet = NextOggPacket(mTheoraState); } while (packet && mTheoraState->IsHeader(packet)); if (!packet) { mVideoQueue.Finish(); return false; } nsAutoReleasePacket autoRelease(packet); parsed++; NS_ASSERTION(packet && packet->granulepos != -1, "Must know first packet's granulepos"); bool eos = packet->e_o_s; PRInt64 frameEndTime = mTheoraState->Time(packet->granulepos); if (!aKeyframeSkip || (th_packet_iskeyframe(packet) && frameEndTime >= aTimeThreshold)) { aKeyframeSkip = false; nsresult res = DecodeTheora(packet, aTimeThreshold); decoded++; if (NS_FAILED(res)) { return false; } } if (eos) { // We've encountered an end of bitstream packet. Inform the queue that // there will be no more frames. mVideoQueue.Finish(); return false; } return true; } PRInt64 nsOggReader::ReadOggPage(ogg_page* aPage) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); int ret = 0; while((ret = ogg_sync_pageseek(&mOggState, aPage)) <= 0) { if (ret < 0) { // Lost page sync, have to skip up to next page. mPageOffset += -ret; continue; } // Returns a buffer that can be written too // with the given size. This buffer is stored // in the ogg synchronisation structure. char* buffer = ogg_sync_buffer(&mOggState, 4096); NS_ASSERTION(buffer, "ogg_sync_buffer failed"); // Read from the stream into the buffer PRUint32 bytesRead = 0; nsresult rv = mDecoder->GetStream()->Read(buffer, 4096, &bytesRead); if (NS_FAILED(rv) || (bytesRead == 0 && ret == 0)) { // End of file. return -1; } mDecoder->NotifyBytesConsumed(bytesRead); // Update the synchronisation layer with the number // of bytes written to the buffer ret = ogg_sync_wrote(&mOggState, bytesRead); NS_ENSURE_TRUE(ret == 0, -1); } PRInt64 offset = mPageOffset; mPageOffset += aPage->header_len + aPage->body_len; return offset; } ogg_packet* nsOggReader::NextOggPacket(nsOggCodecState* aCodecState) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); if (!aCodecState || !aCodecState->mActive) { return nsnull; } ogg_packet* packet; while ((packet = aCodecState->PacketOut()) == nsnull) { // The codec state does not have any buffered pages, so try to read another // page from the channel. ogg_page page; if (ReadOggPage(&page) == -1) { return nsnull; } PRUint32 serial = ogg_page_serialno(&page); nsOggCodecState* codecState = nsnull; mCodecStates.Get(serial, &codecState); if (codecState && NS_FAILED(codecState->PageIn(&page))) { return nsnull; } } return packet; } // Returns an ogg page's checksum. static ogg_uint32_t GetChecksum(ogg_page* page) { if (page == 0 || page->header == 0 || page->header_len < 25) { return 0; } const unsigned char* p = page->header + 22; PRUint32 c = p[0] + (p[1] << 8) + (p[2] << 16) + (p[3] << 24); return c; } PRInt64 nsOggReader::RangeStartTime(PRInt64 aOffset) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); nsMediaStream* stream = mDecoder->GetStream(); NS_ENSURE_TRUE(stream != nsnull, nsnull); nsresult res = stream->Seek(nsISeekableStream::NS_SEEK_SET, aOffset); NS_ENSURE_SUCCESS(res, nsnull); PRInt64 startTime = 0; nsBuiltinDecoderReader::FindStartTime(startTime); return startTime; } struct nsAutoOggSyncState { nsAutoOggSyncState() { ogg_sync_init(&mState); } ~nsAutoOggSyncState() { ogg_sync_clear(&mState); } ogg_sync_state mState; }; PRInt64 nsOggReader::RangeEndTime(PRInt64 aEndOffset) { NS_ASSERTION(mDecoder->OnStateMachineThread() || mDecoder->OnDecodeThread(), "Should be on state machine or decode thread."); nsMediaStream* stream = mDecoder->GetStream(); NS_ENSURE_TRUE(stream != nsnull, -1); PRInt64 position = stream->Tell(); PRInt64 endTime = RangeEndTime(0, aEndOffset, false); nsresult res = stream->Seek(nsISeekableStream::NS_SEEK_SET, position); NS_ENSURE_SUCCESS(res, -1); return endTime; } PRInt64 nsOggReader::RangeEndTime(PRInt64 aStartOffset, PRInt64 aEndOffset, bool aCachedDataOnly) { nsMediaStream* stream = mDecoder->GetStream(); nsAutoOggSyncState sync; // We need to find the last page which ends before aEndOffset that // has a granulepos that we can convert to a timestamp. We do this by // backing off from aEndOffset until we encounter a page on which we can // interpret the granulepos. If while backing off we encounter a page which // we've previously encountered before, we'll either backoff again if we // haven't found an end time yet, or return the last end time found. const int step = 5000; PRInt64 readStartOffset = aEndOffset; PRInt64 readHead = aEndOffset; PRInt64 endTime = -1; PRUint32 checksumAfterSeek = 0; PRUint32 prevChecksumAfterSeek = 0; bool mustBackOff = false; while (true) { ogg_page page; int ret = ogg_sync_pageseek(&sync.mState, &page); if (ret == 0) { // We need more data if we've not encountered a page we've seen before, // or we've read to the end of file. if (mustBackOff || readHead == aEndOffset || readHead == aStartOffset) { if (endTime != -1 || readStartOffset == 0) { // We have encountered a page before, or we're at the end of file. break; } mustBackOff = false; prevChecksumAfterSeek = checksumAfterSeek; checksumAfterSeek = 0; ogg_sync_reset(&sync.mState); readStartOffset = NS_MAX(static_cast(0), readStartOffset - step); readHead = NS_MAX(aStartOffset, readStartOffset); } PRInt64 limit = NS_MIN(static_cast(PR_UINT32_MAX), aEndOffset - readHead); limit = NS_MAX(static_cast(0), limit); limit = NS_MIN(limit, static_cast(step)); PRUint32 bytesToRead = static_cast(limit); PRUint32 bytesRead = 0; char* buffer = ogg_sync_buffer(&sync.mState, bytesToRead); NS_ASSERTION(buffer, "Must have buffer"); nsresult res; if (aCachedDataOnly) { res = stream->ReadFromCache(buffer, readHead, bytesToRead); NS_ENSURE_SUCCESS(res, -1); bytesRead = bytesToRead; } else { NS_ASSERTION(readHead < aEndOffset, "Stream pos must be before range end"); res = stream->Seek(nsISeekableStream::NS_SEEK_SET, readHead); NS_ENSURE_SUCCESS(res, -1); res = stream->Read(buffer, bytesToRead, &bytesRead); NS_ENSURE_SUCCESS(res, -1); } readHead += bytesRead; // Update the synchronisation layer with the number // of bytes written to the buffer ret = ogg_sync_wrote(&sync.mState, bytesRead); if (ret != 0) { endTime = -1; break; } continue; } if (ret < 0 || ogg_page_granulepos(&page) < 0) { continue; } PRUint32 checksum = GetChecksum(&page); if (checksumAfterSeek == 0) { // This is the first page we've decoded after a backoff/seek. Remember // the page checksum. If we backoff further and encounter this page // again, we'll know that we won't find a page with an end time after // this one, so we'll know to back off again. checksumAfterSeek = checksum; } if (checksum == prevChecksumAfterSeek) { // This page has the same checksum as the first page we encountered // after the last backoff/seek. Since we've already scanned after this // page and failed to find an end time, we may as well backoff again and // try to find an end time from an earlier page. mustBackOff = true; continue; } PRInt64 granulepos = ogg_page_granulepos(&page); int serial = ogg_page_serialno(&page); nsOggCodecState* codecState = nsnull; mCodecStates.Get(serial, &codecState); if (!codecState) { // This page is from a bitstream which we haven't encountered yet. // It's probably from a new "link" in a "chained" ogg. Don't // bother even trying to find a duration... endTime = -1; break; } PRInt64 t = codecState->Time(granulepos); if (t != -1) { endTime = t; } } return endTime; } nsresult nsOggReader::GetSeekRanges(nsTArray& aRanges) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); nsTArray cached; nsresult res = mDecoder->GetStream()->GetCachedRanges(cached); NS_ENSURE_SUCCESS(res, res); for (PRUint32 index = 0; index < cached.Length(); index++) { nsByteRange& range = cached[index]; PRInt64 startTime = -1; PRInt64 endTime = -1; if (NS_FAILED(ResetDecode())) { return NS_ERROR_FAILURE; } PRInt64 startOffset = range.mStart; PRInt64 endOffset = range.mEnd; startTime = RangeStartTime(startOffset); if (startTime != -1 && ((endTime = RangeEndTime(endOffset)) != -1)) { NS_ASSERTION(startTime < endTime, "Start time must be before end time"); aRanges.AppendElement(SeekRange(startOffset, endOffset, startTime, endTime)); } } if (NS_FAILED(ResetDecode())) { return NS_ERROR_FAILURE; } return NS_OK; } nsOggReader::SeekRange nsOggReader::SelectSeekRange(const nsTArray& ranges, PRInt64 aTarget, PRInt64 aStartTime, PRInt64 aEndTime, bool aExact) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); PRInt64 so = 0; PRInt64 eo = mDecoder->GetStream()->GetLength(); PRInt64 st = aStartTime; PRInt64 et = aEndTime; for (PRUint32 i = 0; i < ranges.Length(); i++) { const SeekRange &r = ranges[i]; if (r.mTimeStart < aTarget) { so = r.mOffsetStart; st = r.mTimeStart; } if (r.mTimeEnd >= aTarget && r.mTimeEnd < et) { eo = r.mOffsetEnd; et = r.mTimeEnd; } if (r.mTimeStart < aTarget && aTarget <= r.mTimeEnd) { // Target lies exactly in this range. return ranges[i]; } } if (aExact || eo == -1) { return SeekRange(); } return SeekRange(so, eo, st, et); } nsOggReader::IndexedSeekResult nsOggReader::RollbackIndexedSeek(PRInt64 aOffset) { mSkeletonState->Deactivate(); nsMediaStream* stream = mDecoder->GetStream(); NS_ENSURE_TRUE(stream != nsnull, SEEK_FATAL_ERROR); nsresult res = stream->Seek(nsISeekableStream::NS_SEEK_SET, aOffset); NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR); return SEEK_INDEX_FAIL; } nsOggReader::IndexedSeekResult nsOggReader::SeekToKeyframeUsingIndex(PRInt64 aTarget) { nsMediaStream* stream = mDecoder->GetStream(); NS_ENSURE_TRUE(stream != nsnull, SEEK_FATAL_ERROR); if (!HasSkeleton() || !mSkeletonState->HasIndex()) { return SEEK_INDEX_FAIL; } // We have an index from the Skeleton track, try to use it to seek. nsAutoTArray tracks; if (HasVideo()) { tracks.AppendElement(mTheoraState->mSerial); } if (HasAudio()) { tracks.AppendElement(mVorbisState->mSerial); } nsSkeletonState::nsSeekTarget keyframe; if (NS_FAILED(mSkeletonState->IndexedSeekTarget(aTarget, tracks, keyframe))) { // Could not locate a keypoint for the target in the index. return SEEK_INDEX_FAIL; } // Remember original stream read cursor position so we can rollback on failure. PRInt64 tell = stream->Tell(); // Seek to the keypoint returned by the index. if (keyframe.mKeyPoint.mOffset > stream->GetLength() || keyframe.mKeyPoint.mOffset < 0) { // Index must be invalid. return RollbackIndexedSeek(tell); } LOG(PR_LOG_DEBUG, ("Seeking using index to keyframe at offset %lld\n", keyframe.mKeyPoint.mOffset)); nsresult res = stream->Seek(nsISeekableStream::NS_SEEK_SET, keyframe.mKeyPoint.mOffset); NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR); mPageOffset = keyframe.mKeyPoint.mOffset; // We've moved the read set, so reset decode. res = ResetDecode(); NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR); // Check that the page the index thinks is exactly here is actually exactly // here. If not, the index is invalid. ogg_page page; int skippedBytes = 0; PageSyncResult syncres = PageSync(stream, &mOggState, false, mPageOffset, stream->GetLength(), &page, skippedBytes); NS_ENSURE_TRUE(syncres != PAGE_SYNC_ERROR, SEEK_FATAL_ERROR); if (syncres != PAGE_SYNC_OK || skippedBytes != 0) { LOG(PR_LOG_DEBUG, ("Indexed-seek failure: Ogg Skeleton Index is invalid " "or sync error after seek")); return RollbackIndexedSeek(tell); } PRUint32 serial = ogg_page_serialno(&page); if (serial != keyframe.mSerial) { // Serialno of page at offset isn't what the index told us to expect. // Assume the index is invalid. return RollbackIndexedSeek(tell); } nsOggCodecState* codecState = nsnull; mCodecStates.Get(serial, &codecState); if (codecState && codecState->mActive && ogg_stream_pagein(&codecState->mState, &page) != 0) { // Couldn't insert page into the ogg stream, or somehow the stream // is no longer active. return RollbackIndexedSeek(tell); } mPageOffset = keyframe.mKeyPoint.mOffset + page.header_len + page.body_len; return SEEK_OK; } nsresult nsOggReader::SeekInBufferedRange(PRInt64 aTarget, PRInt64 aStartTime, PRInt64 aEndTime, const nsTArray& aRanges, const SeekRange& aRange) { LOG(PR_LOG_DEBUG, ("%p Seeking in buffered data to %lld using bisection search", mDecoder, aTarget)); // We know the exact byte range in which the target must lie. It must // be buffered in the media cache. Seek there. nsresult res = SeekBisection(aTarget, aRange, 0); if (NS_FAILED(res) || !HasVideo()) { return res; } // We have an active Theora bitstream. Decode the next Theora frame, and // extract its keyframe's time. bool eof; do { bool skip = false; eof = !DecodeVideoFrame(skip, 0); { ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor()); if (mDecoder->GetDecodeState() == nsBuiltinDecoderStateMachine::DECODER_STATE_SHUTDOWN) { return NS_ERROR_FAILURE; } } } while (!eof && mVideoQueue.GetSize() == 0); VideoData* video = mVideoQueue.PeekFront(); if (video && !video->mKeyframe) { // First decoded frame isn't a keyframe, seek back to previous keyframe, // otherwise we'll get visual artifacts. NS_ASSERTION(video->mTimecode != -1, "Must have a granulepos"); int shift = mTheoraState->mInfo.keyframe_granule_shift; PRInt64 keyframeGranulepos = (video->mTimecode >> shift) << shift; PRInt64 keyframeTime = mTheoraState->StartTime(keyframeGranulepos); SEEK_LOG(PR_LOG_DEBUG, ("Keyframe for %lld is at %lld, seeking back to it", video->mTime, keyframeTime)); SeekRange k = SelectSeekRange(aRanges, keyframeTime, aStartTime, aEndTime, false); res = SeekBisection(keyframeTime, k, SEEK_FUZZ_USECS); } return res; } nsresult nsOggReader::SeekInUnbuffered(PRInt64 aTarget, PRInt64 aStartTime, PRInt64 aEndTime, const nsTArray& aRanges) { LOG(PR_LOG_DEBUG, ("%p Seeking in unbuffered data to %lld using bisection search", mDecoder, aTarget)); // If we've got an active Theora bitstream, determine the maximum possible // time in usecs which a keyframe could be before a given interframe. We // subtract this from our seek target, seek to the new target, and then // will decode forward to the original seek target. We should encounter a // keyframe in that interval. This prevents us from needing to run two // bisections; one for the seek target frame, and another to find its // keyframe. It's usually faster to just download this extra data, rather // tham perform two bisections to find the seek target's keyframe. We // don't do this offsetting when seeking in a buffered range, // as the extra decoding causes a noticeable speed hit when all the data // is buffered (compared to just doing a bisection to exactly find the // keyframe). PRInt64 keyframeOffsetMs = 0; if (HasVideo() && mTheoraState) { keyframeOffsetMs = mTheoraState->MaxKeyframeOffset(); } PRInt64 seekTarget = NS_MAX(aStartTime, aTarget - keyframeOffsetMs); // Minimize the bisection search space using the known timestamps from the // buffered ranges. SeekRange k = SelectSeekRange(aRanges, seekTarget, aStartTime, aEndTime, false); return SeekBisection(seekTarget, k, SEEK_FUZZ_USECS); } nsresult nsOggReader::Seek(PRInt64 aTarget, PRInt64 aStartTime, PRInt64 aEndTime, PRInt64 aCurrentTime) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); LOG(PR_LOG_DEBUG, ("%p About to seek to %lld", mDecoder, aTarget)); nsresult res; nsMediaStream* stream = mDecoder->GetStream(); NS_ENSURE_TRUE(stream != nsnull, NS_ERROR_FAILURE); if (aTarget == aStartTime) { // We've seeked to the media start. Just seek to the offset of the first // content page. res = stream->Seek(nsISeekableStream::NS_SEEK_SET, 0); NS_ENSURE_SUCCESS(res,res); mPageOffset = 0; res = ResetDecode(); NS_ENSURE_SUCCESS(res,res); NS_ASSERTION(aStartTime != -1, "mStartTime should be known"); { ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor()); mDecoder->UpdatePlaybackPosition(aStartTime); } } else { IndexedSeekResult sres = SeekToKeyframeUsingIndex(aTarget); NS_ENSURE_TRUE(sres != SEEK_FATAL_ERROR, NS_ERROR_FAILURE); if (sres == SEEK_INDEX_FAIL) { // No index or other non-fatal index-related failure. Try to seek // using a bisection search. Determine the already downloaded data // in the media cache, so we can try to seek in the cached data first. nsAutoTArray ranges; res = GetSeekRanges(ranges); NS_ENSURE_SUCCESS(res,res); // Figure out if the seek target lies in a buffered range. SeekRange r = SelectSeekRange(ranges, aTarget, aStartTime, aEndTime, true); if (!r.IsNull()) { // We know the buffered range in which the seek target lies, do a // bisection search in that buffered range. res = SeekInBufferedRange(aTarget, aStartTime, aEndTime, ranges, r); NS_ENSURE_SUCCESS(res,res); } else { // The target doesn't lie in a buffered range. Perform a bisection // search over the whole media, using the known buffered ranges to // reduce the search space. res = SeekInUnbuffered(aTarget, aStartTime, aEndTime, ranges); NS_ENSURE_SUCCESS(res,res); } } } // The decode position must now be either close to the seek target, or // we've seeked to before the keyframe before the seek target. Decode // forward to the seek target frame. return DecodeToTarget(aTarget); } // Reads a page from the media stream. static PageSyncResult PageSync(nsMediaStream* aStream, ogg_sync_state* aState, bool aCachedDataOnly, PRInt64 aOffset, PRInt64 aEndOffset, ogg_page* aPage, int& aSkippedBytes) { aSkippedBytes = 0; // Sync to the next page. int ret = 0; PRUint32 bytesRead = 0; PRInt64 readHead = aOffset; while (ret <= 0) { ret = ogg_sync_pageseek(aState, aPage); if (ret == 0) { char* buffer = ogg_sync_buffer(aState, PAGE_STEP); NS_ASSERTION(buffer, "Must have a buffer"); // Read from the file into the buffer PRInt64 bytesToRead = NS_MIN(static_cast(PAGE_STEP), aEndOffset - readHead); NS_ASSERTION(bytesToRead <= PR_UINT32_MAX, "bytesToRead range check"); if (bytesToRead <= 0) { return PAGE_SYNC_END_OF_RANGE; } nsresult rv = NS_OK; if (aCachedDataOnly) { rv = aStream->ReadFromCache(buffer, readHead, static_cast(bytesToRead)); NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR); bytesRead = static_cast(bytesToRead); } else { rv = aStream->Seek(nsISeekableStream::NS_SEEK_SET, readHead); NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR); rv = aStream->Read(buffer, static_cast(bytesToRead), &bytesRead); NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR); } if (bytesRead == 0 && NS_SUCCEEDED(rv)) { // End of file. return PAGE_SYNC_END_OF_RANGE; } readHead += bytesRead; // Update the synchronisation layer with the number // of bytes written to the buffer ret = ogg_sync_wrote(aState, bytesRead); NS_ENSURE_TRUE(ret == 0, PAGE_SYNC_ERROR); continue; } if (ret < 0) { NS_ASSERTION(aSkippedBytes >= 0, "Offset >= 0"); aSkippedBytes += -ret; NS_ASSERTION(aSkippedBytes >= 0, "Offset >= 0"); continue; } } return PAGE_SYNC_OK; } nsresult nsOggReader::SeekBisection(PRInt64 aTarget, const SeekRange& aRange, PRUint32 aFuzz) { NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread."); nsresult res; nsMediaStream* stream = mDecoder->GetStream(); if (aTarget == aRange.mTimeStart) { if (NS_FAILED(ResetDecode())) { return NS_ERROR_FAILURE; } res = stream->Seek(nsISeekableStream::NS_SEEK_SET, 0); NS_ENSURE_SUCCESS(res,res); mPageOffset = 0; return NS_OK; } // Bisection search, find start offset of last page with end time less than // the seek target. ogg_int64_t startOffset = aRange.mOffsetStart; ogg_int64_t startTime = aRange.mTimeStart; ogg_int64_t startLength = 0; // Length of the page at startOffset. ogg_int64_t endOffset = aRange.mOffsetEnd; ogg_int64_t endTime = aRange.mTimeEnd; ogg_int64_t seekTarget = aTarget; PRInt64 seekLowerBound = NS_MAX(static_cast(0), aTarget - aFuzz); int hops = 0; ogg_int64_t previousGuess = -1; int backsteps = 0; const int maxBackStep = 10; NS_ASSERTION(static_cast(PAGE_STEP) * pow(2.0, maxBackStep) < PR_INT32_MAX, "Backstep calculation must not overflow"); // Seek via bisection search. Loop until we find the offset where the page // before the offset is before the seek target, and the page after the offset // is after the seek target. while (true) { ogg_int64_t duration = 0; double target = 0; ogg_int64_t interval = 0; ogg_int64_t guess = 0; ogg_page page; int skippedBytes = 0; ogg_int64_t pageOffset = 0; ogg_int64_t pageLength = 0; ogg_int64_t granuleTime = -1; bool mustBackoff = false; // Guess where we should bisect to, based on the bit rate and the time // remaining in the interval. Loop until we can determine the time at // the guess offset. while (true) { // Discard any previously buffered packets/pages. if (NS_FAILED(ResetDecode())) { return NS_ERROR_FAILURE; } interval = endOffset - startOffset - startLength; if (interval == 0) { // Our interval is empty, we've found the optimal seek point, as the // page at the start offset is before the seek target, and the page // at the end offset is after the seek target. SEEK_LOG(PR_LOG_DEBUG, ("Interval narrowed, terminating bisection.")); break; } // Guess bisection point. duration = endTime - startTime; target = (double)(seekTarget - startTime) / (double)duration; guess = startOffset + startLength + static_cast((double)interval * target); guess = NS_MIN(guess, endOffset - PAGE_STEP); if (mustBackoff) { // We previously failed to determine the time at the guess offset, // probably because we ran out of data to decode. This usually happens // when we guess very close to the end offset. So reduce the guess // offset using an exponential backoff until we determine the time. SEEK_LOG(PR_LOG_DEBUG, ("Backing off %d bytes, backsteps=%d", static_cast(PAGE_STEP * pow(2.0, backsteps)), backsteps)); guess -= PAGE_STEP * static_cast(pow(2.0, backsteps)); if (guess <= startOffset) { // We've tried to backoff to before the start offset of our seek // range. This means we couldn't find a seek termination position // near the end of the seek range, so just set the seek termination // condition, and break out of the bisection loop. We'll begin // decoding from the start of the seek range. interval = 0; break; } backsteps = NS_MIN(backsteps + 1, maxBackStep); // We reset mustBackoff. If we still need to backoff further, it will // be set to true again. mustBackoff = false; } else { backsteps = 0; } guess = NS_MAX(guess, startOffset + startLength); SEEK_LOG(PR_LOG_DEBUG, ("Seek loop start[o=%lld..%lld t=%lld] " "end[o=%lld t=%lld] " "interval=%lld target=%lf guess=%lld", startOffset, (startOffset+startLength), startTime, endOffset, endTime, interval, target, guess)); NS_ASSERTION(guess >= startOffset + startLength, "Guess must be after range start"); NS_ASSERTION(guess < endOffset, "Guess must be before range end"); NS_ASSERTION(guess != previousGuess, "Guess should be different to previous"); previousGuess = guess; hops++; // Locate the next page after our seek guess, and then figure out the // granule time of the audio and video bitstreams there. We can then // make a bisection decision based on our location in the media. PageSyncResult res = PageSync(stream, &mOggState, false, guess, endOffset, &page, skippedBytes); NS_ENSURE_TRUE(res != PAGE_SYNC_ERROR, NS_ERROR_FAILURE); // We've located a page of length |ret| at |guess + skippedBytes|. // Remember where the page is located. pageOffset = guess + skippedBytes; pageLength = page.header_len + page.body_len; mPageOffset = pageOffset + pageLength; if (res == PAGE_SYNC_END_OF_RANGE) { // Our guess was too close to the end, we've ended up reading the end // page. Backoff exponentially from the end point, in case the last // page/frame/sample is huge. mustBackoff = true; SEEK_LOG(PR_LOG_DEBUG, ("Hit the end of range, backing off")); continue; } // Read pages until we can determine the granule time of the audio and // video bitstream. ogg_int64_t audioTime = -1; ogg_int64_t videoTime = -1; do { // Add the page to its codec state, determine its granule time. PRUint32 serial = ogg_page_serialno(&page); nsOggCodecState* codecState = nsnull; mCodecStates.Get(serial, &codecState); if (codecState && codecState->mActive) { int ret = ogg_stream_pagein(&codecState->mState, &page); NS_ENSURE_TRUE(ret == 0, NS_ERROR_FAILURE); } ogg_int64_t granulepos = ogg_page_granulepos(&page); if (HasAudio() && granulepos > 0 && serial == mVorbisState->mSerial && audioTime == -1) { audioTime = mVorbisState->Time(granulepos); } if (HasVideo() && granulepos > 0 && serial == mTheoraState->mSerial && videoTime == -1) { videoTime = mTheoraState->StartTime(granulepos); } if (mPageOffset == endOffset) { // Hit end of readable data. break; } if (ReadOggPage(&page) == -1) { break; } } while ((mVorbisState && audioTime == -1) || (mTheoraState && videoTime == -1)); NS_ASSERTION(mPageOffset <= endOffset, "Page read cursor should be inside range"); if ((HasAudio() && audioTime == -1) || (HasVideo() && videoTime == -1)) { // We don't have timestamps for all active tracks... if (pageOffset == startOffset + startLength && mPageOffset == endOffset) { // We read the entire interval without finding timestamps for all // active tracks. We know the interval start offset is before the seek // target, and the interval end is after the seek target, and we can't // terminate inside the interval, so we terminate the seek at the // start of the interval. interval = 0; break; } // We should backoff; cause the guess to back off from the end, so // that we've got more room to capture. mustBackoff = true; continue; } // We've found appropriate time stamps here. Proceed to bisect // the search space. granuleTime = NS_MAX(audioTime, videoTime); NS_ASSERTION(granuleTime > 0, "Must get a granuletime"); break; } // End of "until we determine time at guess offset" loop. if (interval == 0) { // Seek termination condition; we've found the page boundary of the // last page before the target, and the first page after the target. SEEK_LOG(PR_LOG_DEBUG, ("Terminating seek at offset=%lld", startOffset)); NS_ASSERTION(startTime < aTarget, "Start time must always be less than target"); res = stream->Seek(nsISeekableStream::NS_SEEK_SET, startOffset); NS_ENSURE_SUCCESS(res,res); mPageOffset = startOffset; if (NS_FAILED(ResetDecode())) { return NS_ERROR_FAILURE; } break; } SEEK_LOG(PR_LOG_DEBUG, ("Time at offset %lld is %lld", guess, granuleTime)); if (granuleTime < seekTarget && granuleTime > seekLowerBound) { // We're within the fuzzy region in which we want to terminate the search. res = stream->Seek(nsISeekableStream::NS_SEEK_SET, pageOffset); NS_ENSURE_SUCCESS(res,res); mPageOffset = pageOffset; if (NS_FAILED(ResetDecode())) { return NS_ERROR_FAILURE; } SEEK_LOG(PR_LOG_DEBUG, ("Terminating seek at offset=%lld", mPageOffset)); break; } if (granuleTime >= seekTarget) { // We've landed after the seek target. NS_ASSERTION(pageOffset < endOffset, "offset_end must decrease"); endOffset = pageOffset; endTime = granuleTime; } else if (granuleTime < seekTarget) { // Landed before seek target. NS_ASSERTION(pageOffset >= startOffset + startLength, "Bisection point should be at or after end of first page in interval"); startOffset = pageOffset; startLength = pageLength; startTime = granuleTime; } NS_ASSERTION(startTime < seekTarget, "Must be before seek target"); NS_ASSERTION(endTime >= seekTarget, "End must be after seek target"); } SEEK_LOG(PR_LOG_DEBUG, ("Seek complete in %d bisections.", hops)); return NS_OK; } nsresult nsOggReader::GetBuffered(nsTimeRanges* aBuffered, PRInt64 aStartTime) { // HasAudio and HasVideo are not used here as they take a lock and cause // a deadlock. Accessing mInfo doesn't require a lock - it doesn't change // after metadata is read and GetBuffered isn't called before metadata is // read. if (!mInfo.mHasVideo && !mInfo.mHasAudio) { // No need to search through the file if there are no audio or video tracks return NS_OK; } nsMediaStream* stream = mDecoder->GetStream(); nsTArray ranges; nsresult res = stream->GetCachedRanges(ranges); NS_ENSURE_SUCCESS(res, res); // Traverse across the buffered byte ranges, determining the time ranges // they contain. nsMediaStream::GetNextCachedData(offset) returns -1 when // offset is after the end of the media stream, or there's no more cached // data after the offset. This loop will run until we've checked every // buffered range in the media, in increasing order of offset. nsAutoOggSyncState sync; for (PRUint32 index = 0; index < ranges.Length(); index++) { // Ensure the offsets are after the header pages. PRInt64 startOffset = ranges[index].mStart; PRInt64 endOffset = ranges[index].mEnd; // Because the granulepos time is actually the end time of the page, // we special-case (startOffset == 0) so that the first // buffered range always appears to be buffered from the media start // time, rather than from the end-time of the first page. PRInt64 startTime = (startOffset == 0) ? aStartTime : -1; // Find the start time of the range. Read pages until we find one with a // granulepos which we can convert into a timestamp to use as the time of // the start of the buffered range. ogg_sync_reset(&sync.mState); while (startTime == -1) { ogg_page page; PRInt32 discard; PageSyncResult res = PageSync(stream, &sync.mState, true, startOffset, endOffset, &page, discard); if (res == PAGE_SYNC_ERROR) { return NS_ERROR_FAILURE; } else if (res == PAGE_SYNC_END_OF_RANGE) { // Hit the end of range without reading a page, give up trying to // find a start time for this buffered range, skip onto the next one. break; } PRInt64 granulepos = ogg_page_granulepos(&page); if (granulepos == -1) { // Page doesn't have an end time, advance to the next page // until we find one. startOffset += page.header_len + page.body_len; continue; } PRUint32 serial = ogg_page_serialno(&page); if (mVorbisState && serial == mVorbisSerial) { startTime = nsVorbisState::Time(&mVorbisInfo, granulepos); NS_ASSERTION(startTime > 0, "Must have positive start time"); } else if (mTheoraState && serial == mTheoraSerial) { startTime = nsTheoraState::Time(&mTheoraInfo, granulepos); NS_ASSERTION(startTime > 0, "Must have positive start time"); } else if (IsKnownStream(serial)) { // Stream is not the theora or vorbis stream we're playing, // but is one that we have header data for. startOffset += page.header_len + page.body_len; continue; } else { // Page is for a stream we don't know about (possibly a chained // ogg), return an error. return PAGE_SYNC_ERROR; } } if (startTime != -1) { // We were able to find a start time for that range, see if we can // find an end time. PRInt64 endTime = RangeEndTime(startOffset, endOffset, true); if (endTime != -1) { aBuffered->Add((startTime - aStartTime) / static_cast(USECS_PER_S), (endTime - aStartTime) / static_cast(USECS_PER_S)); } } } return NS_OK; } bool nsOggReader::IsKnownStream(PRUint32 aSerial) { for (PRUint32 i = 0; i < mKnownStreams.Length(); i++) { PRUint32 serial = mKnownStreams[i]; if (serial == aSerial) { return true; } } return false; }