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FFmpeg/libavformat/flvdec.c

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/*
* FLV demuxer
* Copyright (c) 2003 The Libav Project
*
* This demuxer will generate a 1 byte extradata for VP6F content.
* It is composed of:
* - upper 4bits: difference between encoded width and visible width
* - lower 4bits: difference between encoded height and visible height
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/avstring.h"
#include "libavutil/dict.h"
#include "libavcodec/bytestream.h"
#include "libavcodec/mpeg4audio.h"
#include "avformat.h"
#include "avio_internal.h"
#include "flv.h"
#define KEYFRAMES_TAG "keyframes"
#define KEYFRAMES_TIMESTAMP_TAG "times"
#define KEYFRAMES_BYTEOFFSET_TAG "filepositions"
typedef struct {
int wrong_dts; ///< wrong dts due to negative cts
} FLVContext;
static int flv_probe(AVProbeData *p)
{
const uint8_t *d;
d = p->buf;
if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0 && AV_RB32(d+5)>8) {
return AVPROBE_SCORE_MAX;
}
return 0;
}
static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
AVCodecContext *acodec = astream->codec;
switch(flv_codecid) {
//no distinction between S16 and S8 PCM codec flags
case FLV_CODECID_PCM:
acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 :
#if HAVE_BIGENDIAN
CODEC_ID_PCM_S16BE;
#else
CODEC_ID_PCM_S16LE;
#endif
break;
case FLV_CODECID_PCM_LE:
acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 : CODEC_ID_PCM_S16LE; break;
case FLV_CODECID_AAC : acodec->codec_id = CODEC_ID_AAC; break;
case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF; break;
case FLV_CODECID_SPEEX:
acodec->codec_id = CODEC_ID_SPEEX;
acodec->sample_rate = 16000;
break;
case FLV_CODECID_MP3 : acodec->codec_id = CODEC_ID_MP3 ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
acodec->codec_id = CODEC_ID_NELLYMOSER;
break;
case FLV_CODECID_NELLYMOSER_16KHZ_MONO:
acodec->sample_rate = 16000;
acodec->codec_id = CODEC_ID_NELLYMOSER;
break;
case FLV_CODECID_NELLYMOSER:
acodec->codec_id = CODEC_ID_NELLYMOSER;
break;
default:
av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
}
}
static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
AVCodecContext *vcodec = vstream->codec;
switch(flv_codecid) {
case FLV_CODECID_H263 : vcodec->codec_id = CODEC_ID_FLV1 ; break;
case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
case FLV_CODECID_SCREEN2: vcodec->codec_id = CODEC_ID_FLASHSV2; break;
case FLV_CODECID_VP6 : vcodec->codec_id = CODEC_ID_VP6F ;
case FLV_CODECID_VP6A :
if(flv_codecid == FLV_CODECID_VP6A)
vcodec->codec_id = CODEC_ID_VP6A;
if(vcodec->extradata_size != 1) {
vcodec->extradata_size = 1;
vcodec->extradata = av_malloc(1);
}
vcodec->extradata[0] = avio_r8(s->pb);
return 1; // 1 byte body size adjustment for flv_read_packet()
case FLV_CODECID_H264:
vcodec->codec_id = CODEC_ID_H264;
return 3; // not 4, reading packet type will consume one byte
default:
av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
vcodec->codec_tag = flv_codecid;
}
return 0;
}
static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize) {
int length = avio_rb16(ioc);
if(length >= buffsize) {
avio_skip(ioc, length);
return -1;
}
avio_read(ioc, buffer, length);
buffer[length] = '\0';
return length;
}
static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, AVStream *vstream, int64_t max_pos) {
unsigned int arraylen = 0, timeslen = 0, fileposlen = 0, i;
double num_val;
char str_val[256];
int64_t *times = NULL;
int64_t *filepositions = NULL;
int ret = AVERROR(ENOSYS);
int64_t initial_pos = avio_tell(ioc);
while (avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
int64_t* current_array;
// Expect array object in context
if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)
break;
arraylen = avio_rb32(ioc);
/*
* Expect only 'times' or 'filepositions' sub-arrays in other case refuse to use such metadata
* for indexing
*/
if (!strcmp(KEYFRAMES_TIMESTAMP_TAG, str_val) && !times) {
if (!(times = av_mallocz(sizeof(*times) * arraylen))) {
ret = AVERROR(ENOMEM);
goto finish;
}
timeslen = arraylen;
current_array = times;
} else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) && !filepositions) {
if (!(filepositions = av_mallocz(sizeof(*filepositions) * arraylen))) {
ret = AVERROR(ENOMEM);
goto finish;
}
fileposlen = arraylen;
current_array = filepositions;
} else // unexpected metatag inside keyframes, will not use such metadata for indexing
break;
for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)
goto finish;
num_val = av_int2dbl(avio_rb64(ioc));
current_array[i] = num_val;
}
if (times && filepositions) {
// All done, exiting at a position allowing amf_parse_object
// to finish parsing the object
ret = 0;
break;
}
}
if (timeslen == fileposlen)
for(i = 0; i < arraylen; i++)
av_add_index_entry(vstream, filepositions[i], times[i]*1000, 0, 0, AVINDEX_KEYFRAME);
else
av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");
finish:
av_freep(&times);
av_freep(&filepositions);
// If we got unexpected data, but successfully reset back to
// the start pos, the caller can continue parsing
if (ret < 0 && avio_seek(ioc, initial_pos, SEEK_SET) > 0)
return 0;
return ret;
}
static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {
AVCodecContext *acodec, *vcodec;
AVIOContext *ioc;
AMFDataType amf_type;
char str_val[256];
double num_val;
num_val = 0;
ioc = s->pb;
amf_type = avio_r8(ioc);
switch(amf_type) {
case AMF_DATA_TYPE_NUMBER:
num_val = av_int2dbl(avio_rb64(ioc)); break;
case AMF_DATA_TYPE_BOOL:
num_val = avio_r8(ioc); break;
case AMF_DATA_TYPE_STRING:
if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
return -1;
break;
case AMF_DATA_TYPE_OBJECT: {
unsigned int keylen;
if (key && !strcmp(KEYFRAMES_TAG, key) && depth == 1)
if (parse_keyframes_index(s, ioc, vstream, max_pos) < 0)
return -1;
while(avio_tell(ioc) < max_pos - 2 && (keylen = avio_rb16(ioc))) {
avio_skip(ioc, keylen); //skip key string
if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
return -1; //if we couldn't skip, bomb out.
}
if(avio_r8(ioc) != AMF_END_OF_OBJECT)
return -1;
}
break;
case AMF_DATA_TYPE_NULL:
case AMF_DATA_TYPE_UNDEFINED:
case AMF_DATA_TYPE_UNSUPPORTED:
break; //these take up no additional space
case AMF_DATA_TYPE_MIXEDARRAY:
avio_skip(ioc, 4); //skip 32-bit max array index
while(avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
//this is the only case in which we would want a nested parse to not skip over the object
if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
return -1;
}
if(avio_r8(ioc) != AMF_END_OF_OBJECT)
return -1;
break;
case AMF_DATA_TYPE_ARRAY: {
unsigned int arraylen, i;
arraylen = avio_rb32(ioc);
for(i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
return -1; //if we couldn't skip, bomb out.
}
}
break;
case AMF_DATA_TYPE_DATE:
avio_skip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
break;
default: //unsupported type, we couldn't skip
return -1;
}
if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
acodec = astream ? astream->codec : NULL;
vcodec = vstream ? vstream->codec : NULL;
if(amf_type == AMF_DATA_TYPE_BOOL) {
av_strlcpy(str_val, num_val > 0 ? "true" : "false", sizeof(str_val));
av_dict_set(&s->metadata, key, str_val, 0);
} else if(amf_type == AMF_DATA_TYPE_NUMBER) {
snprintf(str_val, sizeof(str_val), "%.f", num_val);
av_dict_set(&s->metadata, key, str_val, 0);
if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
else if(!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))
vcodec->bit_rate = num_val * 1024.0;
else if(!strcmp(key, "audiodatarate") && acodec && 0 <= (int)(num_val * 1024.0))
acodec->bit_rate = num_val * 1024.0;
} else if (amf_type == AMF_DATA_TYPE_STRING)
av_dict_set(&s->metadata, key, str_val, 0);
}
return 0;
}
static int flv_read_metabody(AVFormatContext *s, int64_t next_pos) {
AMFDataType type;
AVStream *stream, *astream, *vstream;
AVIOContext *ioc;
int i;
char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
astream = NULL;
vstream = NULL;
ioc = s->pb;
//first object needs to be "onMetaData" string
type = avio_r8(ioc);
if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
return -1;
//find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
for(i = 0; i < s->nb_streams; i++) {
stream = s->streams[i];
if (stream->codec->codec_type == AVMEDIA_TYPE_AUDIO) astream = stream;
else if(stream->codec->codec_type == AVMEDIA_TYPE_VIDEO) vstream = stream;
}
//parse the second object (we want a mixed array)
if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
return -1;
return 0;
}
static AVStream *create_stream(AVFormatContext *s, int is_audio){
AVStream *st = av_new_stream(s, is_audio);
if (!st)
return NULL;
st->codec->codec_type = is_audio ? AVMEDIA_TYPE_AUDIO : AVMEDIA_TYPE_VIDEO;
av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
return st;
}
static int flv_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
int offset, flags;
avio_skip(s->pb, 4);
flags = avio_r8(s->pb);
/* old flvtool cleared this field */
/* FIXME: better fix needed */
if (!flags) {
flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
}
if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
!= (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
s->ctx_flags |= AVFMTCTX_NOHEADER;
if(flags & FLV_HEADER_FLAG_HASVIDEO){
if(!create_stream(s, 0))
return AVERROR(ENOMEM);
}
if(flags & FLV_HEADER_FLAG_HASAUDIO){
if(!create_stream(s, 1))
return AVERROR(ENOMEM);
}
offset = avio_rb32(s->pb);
avio_seek(s->pb, offset, SEEK_SET);
avio_skip(s->pb, 4);
s->start_time = 0;
return 0;
}
static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
{
av_free(st->codec->extradata);
st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
if (!st->codec->extradata)
return AVERROR(ENOMEM);
st->codec->extradata_size = size;
avio_read(s->pb, st->codec->extradata, st->codec->extradata_size);
return 0;
}
static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
{
FLVContext *flv = s->priv_data;
int ret, i, type, size, flags, is_audio;
int64_t next, pos;
int64_t dts, pts = AV_NOPTS_VALUE;
AVStream *st = NULL;
for(;;avio_skip(s->pb, 4)){ /* pkt size is repeated at end. skip it */
pos = avio_tell(s->pb);
type = avio_r8(s->pb);
size = avio_rb24(s->pb);
dts = avio_rb24(s->pb);
dts |= avio_r8(s->pb) << 24;
av_dlog(s, "type:%d, size:%d, dts:%"PRId64"\n", type, size, dts);
if (s->pb->eof_reached)
return AVERROR_EOF;
avio_skip(s->pb, 3); /* stream id, always 0 */
flags = 0;
if(size == 0)
continue;
next= size + avio_tell(s->pb);
if (type == FLV_TAG_TYPE_AUDIO) {
is_audio=1;
flags = avio_r8(s->pb);
size--;
} else if (type == FLV_TAG_TYPE_VIDEO) {
is_audio=0;
flags = avio_r8(s->pb);
size--;
if ((flags & 0xf0) == 0x50) /* video info / command frame */
goto skip;
} else {
if (type == FLV_TAG_TYPE_META && size > 13+1+4)
flv_read_metabody(s, next);
else /* skip packet */
av_log(s, AV_LOG_DEBUG, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
skip:
avio_seek(s->pb, next, SEEK_SET);
continue;
}
/* skip empty data packets */
if (!size)
continue;
/* now find stream */
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
if (st->id == is_audio)
break;
}
if(i == s->nb_streams){
av_log(s, AV_LOG_ERROR, "invalid stream\n");
st= create_stream(s, is_audio);
s->ctx_flags &= ~AVFMTCTX_NOHEADER;
}
av_dlog(s, "%d %X %d \n", is_audio, flags, st->discard);
if( (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY || is_audio))
||(st->discard >= AVDISCARD_BIDIR && ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
|| st->discard >= AVDISCARD_ALL
){
avio_seek(s->pb, next, SEEK_SET);
continue;
}
if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
break;
}
// if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
if(s->pb->seekable && (!s->duration || s->duration==AV_NOPTS_VALUE)){
int size;
const int64_t pos= avio_tell(s->pb);
const int64_t fsize= avio_size(s->pb);
avio_seek(s->pb, fsize-4, SEEK_SET);
size= avio_rb32(s->pb);
avio_seek(s->pb, fsize-3-size, SEEK_SET);
if(size == avio_rb24(s->pb) + 11){
uint32_t ts = avio_rb24(s->pb);
ts |= avio_r8(s->pb) << 24;
s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
}
avio_seek(s->pb, pos, SEEK_SET);
}
if(is_audio){
if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {
st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
}
if(!st->codec->codec_id){
flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
}
}else{
size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
}
if (st->codec->codec_id == CODEC_ID_AAC ||
st->codec->codec_id == CODEC_ID_H264) {
int type = avio_r8(s->pb);
size--;
if (st->codec->codec_id == CODEC_ID_H264) {
int32_t cts = (avio_rb24(s->pb)+0xff800000)^0xff800000; // sign extension
pts = dts + cts;
if (cts < 0) { // dts are wrong
flv->wrong_dts = 1;
av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");
}
if (flv->wrong_dts)
dts = AV_NOPTS_VALUE;
}
if (type == 0) {
if ((ret = flv_get_extradata(s, st, size)) < 0)
return ret;
if (st->codec->codec_id == CODEC_ID_AAC) {
MPEG4AudioConfig cfg;
ff_mpeg4audio_get_config(&cfg, st->codec->extradata,
st->codec->extradata_size);
st->codec->channels = cfg.channels;
if (cfg.ext_sample_rate)
st->codec->sample_rate = cfg.ext_sample_rate;
else
st->codec->sample_rate = cfg.sample_rate;
av_dlog(s, "mp4a config channels %d sample rate %d\n",
st->codec->channels, st->codec->sample_rate);
}
ret = AVERROR(EAGAIN);
goto leave;
}
}
/* skip empty data packets */
if (!size) {
ret = AVERROR(EAGAIN);
goto leave;
}
ret= av_get_packet(s->pb, pkt, size);
if (ret < 0) {
return AVERROR(EIO);
}
/* note: we need to modify the packet size here to handle the last
packet */
pkt->size = ret;
pkt->dts = dts;
pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;
pkt->stream_index = st->index;
if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
pkt->flags |= AV_PKT_FLAG_KEY;
leave:
avio_skip(s->pb, 4);
return ret;
}
static int flv_read_seek(AVFormatContext *s, int stream_index,
int64_t ts, int flags)
{
return avio_seek_time(s->pb, stream_index, ts, flags);
}
#if 0 /* don't know enough to implement this */
static int flv_read_seek2(AVFormatContext *s, int stream_index,
int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
int ret = AVERROR(ENOSYS);
if (ts - min_ts > (uint64_t)(max_ts - ts)) flags |= AVSEEK_FLAG_BACKWARD;
if (!s->pb->seekable) {
if (stream_index < 0) {
stream_index = av_find_default_stream_index(s);
if (stream_index < 0)
return -1;
/* timestamp for default must be expressed in AV_TIME_BASE units */
ts = av_rescale_rnd(ts, 1000, AV_TIME_BASE,
flags & AVSEEK_FLAG_BACKWARD ? AV_ROUND_DOWN : AV_ROUND_UP);
}
ret = avio_seek_time(s->pb, stream_index, ts, flags);
}
if (ret == AVERROR(ENOSYS))
ret = av_seek_frame(s, stream_index, ts, flags);
return ret;
}
#endif
AVInputFormat ff_flv_demuxer = {
"flv",
NULL_IF_CONFIG_SMALL("FLV format"),
sizeof(FLVContext),
flv_probe,
flv_read_header,
flv_read_packet,
.read_seek = flv_read_seek,
#if 0
.read_seek2 = flv_read_seek2,
#endif
.extensions = "flv",
.value = CODEC_ID_FLV1,
};
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