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Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
137 lines
4.6 KiB
C
137 lines
4.6 KiB
C
/*
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Copyright (C) 2008 Reimar Döffinger
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Permission is hereby granted, free of charge, to any person
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obtaining a copy of this software and associated documentation
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files (the "Software"), to deal in the Software without
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restriction, including without limitation the rights to use, copy,
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modify, merge, publish, distribute, sublicense, and/or sell copies
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of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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DEALINGS IN THE SOFTWARE.
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**/
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#include <stdlib.h>
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#include "libavutil/bswap.h"
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#include "libavutil/avstring.h"
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#include "libavutil/channel_layout.h"
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#include "libavcodec/get_bits.h"
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#include "libavcodec/bytestream.h"
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#include "avformat.h"
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#include "internal.h"
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#include "oggdec.h"
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struct speex_params {
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int packet_size;
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int final_packet_duration;
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int seq;
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};
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static int speex_header(AVFormatContext *s, int idx) {
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struct ogg *ogg = s->priv_data;
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struct ogg_stream *os = ogg->streams + idx;
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struct speex_params *spxp = os->private;
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AVStream *st = s->streams[idx];
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uint8_t *p = os->buf + os->pstart;
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if (!spxp) {
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spxp = av_mallocz(sizeof(*spxp));
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if (!spxp)
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return AVERROR(ENOMEM);
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os->private = spxp;
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}
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if (spxp->seq > 1)
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return 0;
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if (spxp->seq == 0) {
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int frames_per_packet;
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
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st->codecpar->codec_id = AV_CODEC_ID_SPEEX;
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st->codecpar->sample_rate = AV_RL32(p + 36);
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st->codecpar->channels = AV_RL32(p + 48);
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if (st->codecpar->channels < 1 || st->codecpar->channels > 2) {
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av_log(s, AV_LOG_ERROR, "invalid channel count. Speex must be mono or stereo.\n");
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return AVERROR_INVALIDDATA;
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}
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st->codecpar->channel_layout = st->codecpar->channels == 1 ? AV_CH_LAYOUT_MONO :
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AV_CH_LAYOUT_STEREO;
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spxp->packet_size = AV_RL32(p + 56);
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frames_per_packet = AV_RL32(p + 64);
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if (frames_per_packet)
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spxp->packet_size *= frames_per_packet;
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st->codecpar->extradata_size = os->psize;
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st->codecpar->extradata = av_malloc(st->codecpar->extradata_size
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+ AV_INPUT_BUFFER_PADDING_SIZE);
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memcpy(st->codecpar->extradata, p, st->codecpar->extradata_size);
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avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
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} else
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ff_vorbis_stream_comment(s, st, p, os->psize);
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spxp->seq++;
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return 1;
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}
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static int ogg_page_packets(struct ogg_stream *os)
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{
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int i;
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int packets = 0;
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for (i = 0; i < os->nsegs; i++)
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if (os->segments[i] < 255)
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packets++;
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return packets;
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}
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static int speex_packet(AVFormatContext *s, int idx)
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{
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struct ogg *ogg = s->priv_data;
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struct ogg_stream *os = ogg->streams + idx;
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struct speex_params *spxp = os->private;
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int packet_size = spxp->packet_size;
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if (os->flags & OGG_FLAG_EOS && os->lastpts != AV_NOPTS_VALUE &&
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os->granule > 0) {
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/* first packet of final page. we have to calculate the final packet
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duration here because it is the only place we know the next-to-last
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granule position. */
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spxp->final_packet_duration = os->granule - os->lastpts -
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packet_size * (ogg_page_packets(os) - 1);
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}
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if (!os->lastpts && os->granule > 0)
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/* first packet */
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os->lastpts = os->lastdts = os->granule - packet_size *
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ogg_page_packets(os);
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if (os->flags & OGG_FLAG_EOS && os->segp == os->nsegs &&
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spxp->final_packet_duration)
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/* final packet */
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os->pduration = spxp->final_packet_duration;
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else
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os->pduration = packet_size;
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return 0;
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}
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const struct ogg_codec ff_speex_codec = {
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.magic = "Speex ",
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.magicsize = 8,
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.header = speex_header,
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.packet = speex_packet,
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.nb_header = 2,
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};
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