On Tue, May 15, 2018 at 12:23 PM, Aman Gupta <ffm...@tmm1.net> wrote:
> From: Aman Gupta <a...@tmm1.net> > > This new optional flag makes it easier to deal with mpegts > samples where the PMT is updated and elementary streams move > to different PIDs in the middle of playback. > > Previously, new AVStreams were created per PID, and it was up > to the user to figure out which streams had migrated to a new PID > (by iterating over the list of AVProgram and making guesses), and > switch seamlessly to the new AVStream during playback. > > Transcoding or remuxing these streams with ffmpeg on the CLI was > also quite painful, and the user would need to extract each set of > PIDs into a separate file and then stitch them back together. > > With this new option, the mpegts demuxer will automatically detect > PMT changes and feed data from the new PID to the original AVStream > that was created for the orignal PID. For mpegts samples with > stream_identifier_descriptor available, the unique ID is used to merge > PIDs together. If the stream id is not available, the demuxer attempts > to map PIDs based on their order and relation to the PCR pid. > > With this change, I am able to playback and transcode/remux these > two samples which previously caused issues: > > https://tmm1.s3.amazonaws.com/pmt-version-change.ts > https://kuroko.fushizen.eu/videos/pid_switch_sample.ts > > I also have another longer sample which contains multiple PMT > changes, some of which change the ES pids and others which do not: > > https://tmm1.s3.amazonaws.com/multiple-pmt-change.ts > > Demuxing this sample with the new option shows several new log > messages as the PMT changes are handled: > > [mpegts @ 0x7ffe18801200] detected PMT change (version=3/4, > pcr_pid=0xf98/0xf9b) > [mpegts @ 0x7ffe18801200] re-using existing video stream 0 (pid=0xf98) > for new pid=0xf9b > [mpegts @ 0x7ffe18801200] re-using existing audio stream 1 (pid=0xf99) > for new pid=0xf9c > [mpegts @ 0x7ffe18801200] re-using existing audio stream 2 (pid=0xf9a) > for new pid=0xf9d > [mpegts @ 0x7ffe18801200] detected PMT change (version=4/5, > pcr_pid=0xf9b/0xfa9) > [mpegts @ 0x7ffe18801200] re-using existing video stream 0 (pid=0xf98) > for new pid=0xfa9 > [mpegts @ 0x7ffe18801200] re-using existing audio stream 1 (pid=0xf99) > for new pid=0xfaa > [mpegts @ 0x7ffe18801200] re-using existing audio stream 2 (pid=0xf9a) > for new pid=0xfab > One issue I found with this patch: if you seek around aggressively sometimes you may encounter a new ES before a PMT, which causes it not to get merged in as expected. I'm adding the following change locally to fix the issue. diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c index f16eae3235..3d8e9da66f 100644 --- a/libavformat/mpegts.c +++ b/libavformat/mpegts.c @@ -1077,6 +1077,8 @@ static int mpegts_push_data(MpegTSFilter *filter, if (!pes->st) { if (ts->skip_changes) goto skip; + if (ts->merge_pmt_versions) + goto skip; /* wait for PMT to merge new stream */ if (!pes->st) pes->st = avformat_new_stream(ts->stream, NULL); This has the side-effect that any pids not advertised in a PMT will be ignored, but I think that's acceptable behavior if you're opting-in to this new feature. Aman > Signed-off-by: Aman Gupta <a...@tmm1.net> > --- > doc/demuxers.texi | 4 ++ > libavformat/mpegts.c | 106 ++++++++++++++++++++++++++++++ > ++-- > tests/fate/mpegts.mak | 5 ++ > tests/ref/fate/mpegts-probe-pmt-merge | 32 ++++++++++ > 4 files changed, 143 insertions(+), 4 deletions(-) > create mode 100644 tests/ref/fate/mpegts-probe-pmt-merge > > diff --git a/doc/demuxers.texi b/doc/demuxers.texi > index e7c2abce57..2f7d7e0f3a 100644 > --- a/doc/demuxers.texi > +++ b/doc/demuxers.texi > @@ -552,6 +552,10 @@ Show the detected raw packet size, cannot be set by > the user. > Scan and combine all PMTs. The value is an integer with value from -1 > to 1 (-1 means automatic setting, 1 means enabled, 0 means > disabled). Default value is -1. > + > +@item merge_pmt_versions > +Re-use existing streams when a PMT's version is updated and elementary > +streams move to different PIDs. Default value is 0. > @end table > > @section mpjpeg > diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c > index 27b1c30a44..f16eae3235 100644 > --- a/libavformat/mpegts.c > +++ b/libavformat/mpegts.c > @@ -84,6 +84,8 @@ typedef struct MpegTSSectionFilter { > unsigned int end_of_section_reached : 1; > SectionCallback *section_cb; > void *opaque; > + int orig_pcr_pid; /* pmt specific */ > + int last_pcr_pid; > } MpegTSSectionFilter; > > struct MpegTSFilter { > @@ -147,6 +149,7 @@ struct MpegTSContext { > int scan_all_pmts; > > int resync_size; > + int merge_pmt_versions; > > /******************************************/ > /* private mpegts data */ > @@ -172,6 +175,8 @@ static const AVOption options[] = { > {.i64 = 0}, 0, 0, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_EXPORT | > AV_OPT_FLAG_READONLY }, > {"scan_all_pmts", "scan and combine all PMTs", > offsetof(MpegTSContext, scan_all_pmts), AV_OPT_TYPE_BOOL, > {.i64 = -1}, -1, 1, AV_OPT_FLAG_DECODING_PARAM }, > + {"merge_pmt_versions", "re-use streams when PMT's version/pids > change", offsetof(MpegTSContext, merge_pmt_versions), AV_OPT_TYPE_BOOL, > + {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM }, > {"skip_changes", "skip changing / adding streams / programs", > offsetof(MpegTSContext, skip_changes), AV_OPT_TYPE_BOOL, > {.i64 = 0}, 0, 1, 0 }, > {"skip_clear", "skip clearing programs", offsetof(MpegTSContext, > skip_clear), AV_OPT_TYPE_BOOL, > @@ -1073,7 +1078,8 @@ static int mpegts_push_data(MpegTSFilter *filter, > if (ts->skip_changes) > goto skip; > > - pes->st = avformat_new_stream(ts->stream, NULL); > + if (!pes->st) > + pes->st = avformat_new_stream(ts->stream, > NULL); > if (!pes->st) > return AVERROR(ENOMEM); > pes->st->id = pes->pid; > @@ -1983,6 +1989,69 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, > AVStream *st, int stream_type > return 0; > } > > +static AVStream *find_matching_stream(MpegTSContext *ts, int pid, > + int stream_id, > + int pcr_pid, int orig_pcr_pid) > +{ > + AVFormatContext *s = ts->stream; > + int i, orig_pid = orig_pcr_pid + (pid - pcr_pid); > + AVStream *found = NULL; > + > + for (i = 0; i < s->nb_streams; i++) { > + AVStream *st = s->streams[i]; > + if (stream_id != -1) { > + if (st->stream_identifier == stream_id+1) { > + found = st; > + break; > + } > + } else if (pcr_pid != orig_pcr_pid && st->id == orig_pid) { > + found = st; > + break; > + } > + } > + > + if (found) { > + av_log(ts->stream, AV_LOG_DEBUG, "re-using existing %s stream %d > (pid=0x%x) for new pid=0x%x\n", > + av_get_media_type_string(found->codecpar->codec_type), i, > found->id, pid); > + } > + > + return found; > +} > + > +static int parse_stream_identifier_desc(const uint8_t *p, const uint8_t > *p_end) > +{ > + const uint8_t **pp = &p; > + const uint8_t *desc_list_end; > + const uint8_t *desc_end; > + int desc_list_len; > + int desc_len, desc_tag; > + > + desc_list_len = get16(pp, p_end); > + if (desc_list_len < 0) > + return -1; > + desc_list_len &= 0xfff; > + desc_list_end = p + desc_list_len; > + if (desc_list_end > p_end) > + return -1; > + > + while (1) { > + desc_tag = get8(pp, desc_list_end); > + if (desc_tag < 0) > + return -1; > + desc_len = get8(pp, desc_list_end); > + if (desc_len < 0) > + return -1; > + desc_end = *pp + desc_len; > + if (desc_end > desc_list_end) > + return -1; > + > + if (desc_tag == 0x52) { > + return get8(pp, desc_end); > + } > + *pp = desc_end; > + } > +} > + > static int is_pes_stream(int stream_type, uint32_t prog_reg_desc) > { > return !(stream_type == 0x13 || > @@ -2000,6 +2069,8 @@ static void pmt_cb(MpegTSFilter *filter, const > uint8_t *section, int section_len > int program_info_length, pcr_pid, pid, stream_type; > int desc_list_len; > uint32_t prog_reg_desc = 0; /* registration descriptor */ > + int last_ver = tssf->last_ver; > + int stream_id = -1; > > int mp4_descr_count = 0; > Mp4Descr mp4_descr[MAX_MP4_DESCR_COUNT] = { { 0 } }; > @@ -2032,6 +2103,14 @@ static void pmt_cb(MpegTSFilter *filter, const > uint8_t *section, int section_len > pcr_pid &= 0x1fff; > add_pid_to_pmt(ts, h->id, pcr_pid); > set_pcr_pid(ts->stream, h->id, pcr_pid); > + if (!tssf->orig_pcr_pid) > + tssf->orig_pcr_pid = pcr_pid; > + > + if (last_ver != -1 && h->version != last_ver) { > + av_log(ts->stream, AV_LOG_DEBUG, "detected PMT change > (version=%d/%d, pcr_pid=0x%x/0x%x)\n", > + last_ver, h->version, tssf->last_pcr_pid, pcr_pid); > + } > + tssf->last_pcr_pid = pcr_pid; > > av_log(ts->stream, AV_LOG_TRACE, "pcr_pid=0x%x\n", pcr_pid); > > @@ -2083,14 +2162,22 @@ static void pmt_cb(MpegTSFilter *filter, const > uint8_t *section, int section_len > if (pid < 0) > goto out; > pid &= 0x1fff; > + stream_id = parse_stream_identifier_desc(p, p_end); > if (pid == ts->current_pid) > goto out; > > /* now create stream */ > if (ts->pids[pid] && ts->pids[pid]->type == MPEGTS_PES) { > pes = ts->pids[pid]->u.pes_filter.opaque; > + if (ts->merge_pmt_versions && !pes->st) { > + st = find_matching_stream(ts, pid, stream_id, pcr_pid, > tssf->orig_pcr_pid); > + if (st) { > + pes->st = st; > + pes->stream_type = stream_type; > + } > + } > if (!pes->st) { > - pes->st = avformat_new_stream(pes->stream, NULL); > + pes->st = avformat_new_stream(pes->stream, NULL); > if (!pes->st) > goto out; > pes->st->id = pes->pid; > @@ -2100,7 +2187,14 @@ static void pmt_cb(MpegTSFilter *filter, const > uint8_t *section, int section_len > if (ts->pids[pid]) > mpegts_close_filter(ts, ts->pids[pid]); // wrongly added > sdt filter probably > pes = add_pes_stream(ts, pid, pcr_pid); > - if (pes) { > + if (ts->merge_pmt_versions && pes && !pes->st) { > + st = find_matching_stream(ts, pid, stream_id, pcr_pid, > tssf->orig_pcr_pid); > + if (st) { > + pes->st = st; > + pes->stream_type = stream_type; > + } > + } > + if (pes && !pes->st) { > st = avformat_new_stream(pes->stream, NULL); > if (!st) > goto out; > @@ -2110,7 +2204,11 @@ static void pmt_cb(MpegTSFilter *filter, const > uint8_t *section, int section_len > int idx = ff_find_stream_index(ts->stream, pid); > if (idx >= 0) { > st = ts->stream->streams[idx]; > - } else { > + } > + if (ts->merge_pmt_versions && !st) { > + st = find_matching_stream(ts, pid, stream_id, pcr_pid, > tssf->orig_pcr_pid); > + } > + if (!st) { > st = avformat_new_stream(ts->stream, NULL); > if (!st) > goto out; > diff --git a/tests/fate/mpegts.mak b/tests/fate/mpegts.mak > index 2b128492e0..bbcbfc47b2 100644 > --- a/tests/fate/mpegts.mak > +++ b/tests/fate/mpegts.mak > @@ -15,6 +15,11 @@ fate-mpegts-probe-program: SRC = > $(TARGET_SAMPLES)/mpegts/loewe.ts > fate-mpegts-probe-program: CMD = run $(PROBE_CODEC_NAME_COMMAND) > -select_streams p:769:v:0 -i "$(SRC)" > > > +FATE_MPEGTS_PROBE-$(call DEMDEC, MPEGTS) += fate-mpegts-probe-pmt-merge > +fate-mpegts-probe-pmt-merge: SRC = $(TARGET_SAMPLES)/mpegts/pmtchange.ts > +fate-mpegts-probe-pmt-merge: CMD = run $(PROBE_CODEC_NAME_COMMAND) > -merge_pmt_versions 1 -i "$(SRC)" > + > + > FATE_SAMPLES_FFPROBE += $(FATE_MPEGTS_PROBE-yes) > > fate-mpegts: $(FATE_MPEGTS_PROBE-yes) > diff --git a/tests/ref/fate/mpegts-probe-pmt-merge > b/tests/ref/fate/mpegts-probe-pmt-merge > new file mode 100644 > index 0000000000..6e424af5d2 > --- /dev/null > +++ b/tests/ref/fate/mpegts-probe-pmt-merge > @@ -0,0 +1,32 @@ > +[PROGRAM] > +[STREAM] > +codec_name=ac3 > +[/STREAM] > +[STREAM] > +codec_name=ac3 > +[/STREAM] > +[STREAM] > +codec_name=ac3 > +[/STREAM] > +[STREAM] > +codec_name=mpeg2video > +[/STREAM] > +[STREAM] > +codec_name=scte_35 > +[/STREAM] > +[/PROGRAM] > +[STREAM] > +codec_name=ac3 > +[/STREAM] > +[STREAM] > +codec_name=ac3 > +[/STREAM] > +[STREAM] > +codec_name=ac3 > +[/STREAM] > +[STREAM] > +codec_name=mpeg2video > +[/STREAM] > +[STREAM] > +codec_name=scte_35 > +[/STREAM] > -- > 2.14.2 > > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
