[FFmpeg-devel] [PATCH] avformat/mpegtsenc: Add option to mark stream begin as discontinuous

Michael Niedermayer michael at niedermayer.cc
Wed Nov 2 17:32:56 EET 2016


On Wed, Nov 02, 2016 at 10:31:38PM +0800, Steven Liu wrote:
> 2016-11-02 7:51 GMT+08:00 Michael Niedermayer <michael at niedermayer.cc>:
> 
> > This avoids continuity check failures in concatenated streams
> >
> > TODO: docs
> >
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  libavformat/mpegtsenc.c | 26 ++++++++++++++++++++++++++
> >  1 file changed, 26 insertions(+)
> >
> > diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
> > index 3ad3de7..71a6642 100644
> > --- a/libavformat/mpegtsenc.c
> > +++ b/libavformat/mpegtsenc.c
> > @@ -46,6 +46,7 @@
> >  typedef struct MpegTSSection {
> >      int pid;
> >      int cc;
> > +    int discontinuity;
> >      void (*write_packet)(struct MpegTSSection *s, const uint8_t *packet);
> >      void *opaque;
> >  } MpegTSSection;
> > @@ -104,6 +105,7 @@ typedef struct MpegTSWrite {
> >  #define MPEGTS_FLAG_AAC_LATM        0x02
> >  #define MPEGTS_FLAG_PAT_PMT_AT_FRAMES           0x04
> >  #define MPEGTS_FLAG_SYSTEM_B        0x08
> > +#define MPEGTS_FLAG_DISCONT         0x10
> >      int flags;
> >      int copyts;
> >      int tables_version;
> > @@ -153,6 +155,12 @@ static void mpegts_write_section(MpegTSSection *s,
> > uint8_t *buf, int len)
> >          *q++  = s->pid;
> >          s->cc = s->cc + 1 & 0xf;
> >          *q++  = 0x10 | s->cc;
> > +        if (s->discontinuity) {
> > +            q[-1] |= 0x20;
> > +            *q++ = 1;
> > +            *q++ = 0x80;
> > +            s->discontinuity = 0;
> > +        }
> >          if (first)
> >              *q++ = 0; /* 0 offset */
> >          len1 = TS_PACKET_SIZE - (q - packet);
> > @@ -223,6 +231,7 @@ typedef struct MpegTSWriteStream {
> >      struct MpegTSService *service;
> >      int pid; /* stream associated pid */
> >      int cc;
> > +    int discontinuity;
> >      int payload_size;
> >      int first_pts_check; ///< first pts check needed
> >      int prev_payload_key;
> > @@ -782,6 +791,7 @@ static int mpegts_init(AVFormatContext *s)
> >          service->pmt.write_packet = section_write_packet;
> >          service->pmt.opaque       = s;
> >          service->pmt.cc           = 15;
> > +        service->pmt.discontinuity= ts->flags & MPEGTS_FLAG_DISCONT;
> >      } else {
> >          for (i = 0; i < s->nb_programs; i++) {
> >              AVProgram *program = s->programs[i];
> > @@ -800,6 +810,7 @@ static int mpegts_init(AVFormatContext *s)
> >              service->pmt.write_packet = section_write_packet;
> >              service->pmt.opaque       = s;
> >              service->pmt.cc           = 15;
> > +            service->pmt.discontinuity= ts->flags & MPEGTS_FLAG_DISCONT;
> >              service->program          = program;
> >          }
> >      }
> > @@ -808,11 +819,13 @@ static int mpegts_init(AVFormatContext *s)
> >      /* Initialize at 15 so that it wraps and is equal to 0 for the
> >       * first packet we write. */
> >      ts->pat.cc           = 15;
> > +    ts->pat.discontinuity= ts->flags & MPEGTS_FLAG_DISCONT;
> >      ts->pat.write_packet = section_write_packet;
> >      ts->pat.opaque       = s;
> >
> >      ts->sdt.pid          = SDT_PID;
> >      ts->sdt.cc           = 15;
> > +    ts->sdt.discontinuity= ts->flags & MPEGTS_FLAG_DISCONT;
> >      ts->sdt.write_packet = section_write_packet;
> >      ts->sdt.opaque       = s;
> >
> > @@ -883,6 +896,7 @@ static int mpegts_init(AVFormatContext *s)
> >          ts_st->payload_dts     = AV_NOPTS_VALUE;
> >          ts_st->first_pts_check = 1;
> >          ts_st->cc              = 15;
> > +        ts_st->discontinuity   = ts->flags & MPEGTS_FLAG_DISCONT;
> >          /* update PCR pid by using the first video stream */
> >          if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
> >              service->pcr_pid == 0x1fff) {
> > @@ -1078,6 +1092,10 @@ static void mpegts_insert_pcr_only(AVFormatContext
> > *s, AVStream *st)
> >      /* Continuity Count field does not increment (see 13818-1 section
> > 2.4.3.3) */
> >      *q++ = TS_PACKET_SIZE - 5; /* Adaptation Field Length */
> >      *q++ = 0x10;               /* Adaptation flags: PCR present */
> > +    if (ts_st->discontinuity) {
> > +        q[-1] |= 0x80;
> > +        ts_st->discontinuity = 0;
> > +    }
> >
> >      /* PCR coded into 6 bytes */
> >      q += write_pcr_bits(q, get_pcr(ts, s->pb));
> > @@ -1195,6 +1213,11 @@ static void mpegts_write_pes(AVFormatContext *s,
> > AVStream *st,
> >          *q++      = ts_st->pid;
> >          ts_st->cc = ts_st->cc + 1 & 0xf;
> >          *q++      = 0x10 | ts_st->cc; // payload indicator + CC
> > +        if (ts_st->discontinuity) {
> > +            set_af_flag(buf, 0x80);
> > +            q = get_ts_payload_start(buf);
> > +            ts_st->discontinuity = 0;
> > +        }
> >          if (key && is_start && pts != AV_NOPTS_VALUE) {
> >              // set Random Access for key frames
> >              if (ts_st->pid == ts_st->service->pcr_pid)
> > @@ -1872,6 +1895,9 @@ static const AVOption options[] = {
> >      { "system_b", "Conform to System B (DVB) instead of System A (ATSC)",
> >        0, AV_OPT_TYPE_CONST, { .i64 = MPEGTS_FLAG_SYSTEM_B }, 0, INT_MAX,
> >        AV_OPT_FLAG_ENCODING_PARAM, "mpegts_flags" },
> > +    { "initial_discontinuity", "Mark initial packets as discontinuous",
> > +      0, AV_OPT_TYPE_CONST, { .i64 = MPEGTS_FLAG_DISCONT }, 0, INT_MAX,
> > +      AV_OPT_FLAG_ENCODING_PARAM, "mpegts_flags" },
> >      // backward compatibility
> >      { "resend_headers", "Reemit PAT/PMT before writing the next packet",
> >        offsetof(MpegTSWrite, reemit_pat_pmt), AV_OPT_TYPE_INT,
> > --
> > 2.10.2
> >
> >
> LGTM

applied

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Old school: Use the lowest level language in which you can solve the problem
            conveniently.
New school: Use the highest level language in which the latest supercomputer
            can solve the problem without the user falling asleep waiting.
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