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Improve init_seek: don't add existing index, find packet size (for M4A)

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bnnm 2016-12-03 01:56:27 +01:00
parent 8cdce2c196
commit 80c8791288
1 changed files with 36 additions and 17 deletions
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53
src/meta/ffmpeg.c
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@ -373,43 +373,58 @@ fail:
* *
* Fortunately seek_frame_generic can use an index to find the correct position. This function reads the * Fortunately seek_frame_generic can use an index to find the correct position. This function reads the
* first frame/packet and sets up index to timestamp 0. This ensures faulty demuxers will seek to 0 correctly. * first frame/packet and sets up index to timestamp 0. This ensures faulty demuxers will seek to 0 correctly.
* Some formats may not seek to 0 even with this though. * Some formats may not seek to 0 even with this, though.
*/ */
static int init_seek(ffmpeg_codec_data * data) { static int init_seek(ffmpeg_codec_data * data) {
int ret, found = 0; int ret, ts_index, found_first = 0;
int64_t ts = 0; int64_t ts = 0;
int64_t pos; /* offset */
int size; /* coded size */
int distance = 0; /* always? */
AVStream * stream; AVStream * stream;
AVPacket * pkt; AVPacket * pkt;
/* read_seek wouldn't use the index, but direct access to FFmpeg's internals is no good */ stream = data->formatCtx->streams[data->streamIndex];
/* if (data->formatCtx->iformat->read_seek || data->formatCtx->iformat->read_seek2)
return; */
pkt = data->lastReadPacket; pkt = data->lastReadPacket;
/* find the first packet */ /* read_seek shouldn't need this index, but direct access to FFmpeg's internals is no good */
while (!found) { /* if (data->formatCtx->iformat->read_seek || data->formatCtx->iformat->read_seek2)
return 0; */
/* some formats already have a proper index (e.g. M4A) */
ts_index = av_index_search_timestamp(stream, ts, AVSEEK_FLAG_ANY);
if (ts_index>=0)
goto test_seek;
/* find the first + second packets to get pos/size */
while (1) {
av_packet_unref(pkt); av_packet_unref(pkt);
ret = av_read_frame(data->formatCtx, pkt); ret = av_read_frame(data->formatCtx, pkt);
if (ret < 0) if (ret < 0)
break; goto fail;
if (pkt->stream_index != data->streamIndex) if (pkt->stream_index != data->streamIndex)
continue; /* ignore non-selected streams */ continue; /* ignore non-selected streams */
found = 1; if (!found_first) { /* first found */
found_first = 1;
pos = pkt->pos;
continue;
} else { /* second found */
size = pkt->pos - pos; /* coded, pkt->size is decoded size */
break;
}
} }
if (!found)
return -1;
/* add index 0 */ /* add index 0 */
stream = data->formatCtx->streams[data->streamIndex]; ret = av_add_index_entry(stream, pos, ts, size, distance, AVINDEX_KEYFRAME);
ret = av_add_index_entry(stream, pkt->pos, ts, pkt->size, 0, AVINDEX_KEYFRAME);
if ( ret < 0 ) if ( ret < 0 )
return ret; return ret;
/* move back to beginning, since we just consumed packets */
test_seek:
/* seek to 0 test / move back to beginning, since we just consumed packets */
ret = avformat_seek_file(data->formatCtx, data->streamIndex, ts, ts, ts, AVSEEK_FLAG_ANY); ret = avformat_seek_file(data->formatCtx, data->streamIndex, ts, ts, ts, AVSEEK_FLAG_ANY);
if ( ret < 0 ) if ( ret < 0 )
return ret; /* we can't even reset_vgmstream the file */ return ret; /* we can't even reset_vgmstream the file */
@ -417,6 +432,10 @@ static int init_seek(ffmpeg_codec_data * data) {
avcodec_flush_buffers(data->codecCtx); avcodec_flush_buffers(data->codecCtx);
return 0; return 0;
fail:
return -1;
} }