On Tue, Jun 28, 2016 at 7:33 AM, Martin Storsjö <[email protected]> wrote: > When writing a fragmented file, we by default write an index pointing > to all the fragments at the end of the file. This causes constantly > increasing memory usage during the muxing. For live streams, the > index might not be useful at all. > > A similar fragment index is written (but at the start of the file) if > the global_sidx flag is set. If ism_lookahead is set, we need to keep > data about the last ism_lookahead+1 fragments. > > If no fragment index is to be written, we don't need to store information > about all fragments, avoiding increasing the memory consumption > linearly with the muxing runtime. > > This fixes out of memory situations with long live mp4 streams. > --- > libavformat/movenc.c | 29 ++++++++++++++++++++++++++--- > libavformat/movenc.h | 1 + > 2 files changed, 27 insertions(+), 3 deletions(-) > > diff --git a/libavformat/movenc.c b/libavformat/movenc.c > index 393442c..31b940a 100644 > --- a/libavformat/movenc.c > +++ b/libavformat/movenc.c > @@ -60,6 +60,7 @@ static const AVOption options[] = { > { "frag_discont", "Signal that the next fragment is discontinuous from > earlier ones", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_FRAG_DISCONT}, > INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" }, > { "delay_moov", "Delay writing the initial moov until the first fragment > is cut, or until the first fragment flush", 0, AV_OPT_TYPE_CONST, {.i64 = > FF_MOV_FLAG_DELAY_MOOV}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, > "movflags" }, > { "global_sidx", "Write a global sidx index at the start of the file", > 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_GLOBAL_SIDX}, INT_MIN, INT_MAX, > AV_OPT_FLAG_ENCODING_PARAM, "movflags" }, > + { "skip_trailer", "Skip writing the mfra/tfra/mfro trailer for > fragmented files", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_SKIP_TRAILER}, > INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" }, > FF_RTP_FLAG_OPTS(MOVMuxContext, rtp_flags), > { "skip_iods", "Skip writing iods atom.", offsetof(MOVMuxContext, > iods_skip), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM}, > { "iods_audio_profile", "iods audio profile atom.", > offsetof(MOVMuxContext, iods_audio_profile), AV_OPT_TYPE_INT, {.i64 = -1}, > -1, 255, AV_OPT_FLAG_ENCODING_PARAM}, > @@ -2732,6 +2733,20 @@ static int mov_add_tfra_entries(AVIOContext *pb, > MOVMuxContext *mov, int tracks, > return 0; > } > > +static void mov_prune_frag_info(MOVMuxContext *mov, int tracks, int max) > +{ > + int i; > + for (i = 0; i < mov->nb_streams; i++) { > + MOVTrack *track = &mov->tracks[i]; > + if ((tracks >= 0 && i != tracks) || !track->entry) > + continue; > + if (track->nb_frag_info > max) { > + memmove(track->frag_info, track->frag_info + > (track->nb_frag_info - max), max * sizeof(*track->frag_info)); > + track->nb_frag_info = max; > + } > + } > +} > + > static int mov_write_tfdt_tag(AVIOContext *pb, MOVTrack *track) > { > int64_t pos = avio_tell(pb); > @@ -2917,8 +2932,16 @@ static int mov_write_moof_tag(AVIOContext *pb, > MOVMuxContext *mov, int tracks, > if (mov->flags & FF_MOV_FLAG_DASH && !(mov->flags & > FF_MOV_FLAG_GLOBAL_SIDX)) > mov_write_sidx_tags(pb, mov, tracks, moof_size + 8 + mdat_size); > > - if ((ret = mov_add_tfra_entries(pb, mov, tracks, moof_size + 8 + > mdat_size)) < 0) > - return ret; > + if (mov->flags & FF_MOV_FLAG_GLOBAL_SIDX || > + !(mov->flags & FF_MOV_FLAG_SKIP_TRAILER) || > + mov->ism_lookahead) { > + if ((ret = mov_add_tfra_entries(pb, mov, tracks, moof_size + 8 + > mdat_size)) < 0) > + return ret; > + if (!(mov->flags & FF_MOV_FLAG_GLOBAL_SIDX) && > + mov->flags & FF_MOV_FLAG_SKIP_TRAILER) { > + mov_prune_frag_info(mov, tracks, mov->ism_lookahead + 1); > + } > + } > > return mov_write_moof_tag_internal(pb, mov, tracks, moof_size); > } > @@ -4389,7 +4412,7 @@ static int mov_write_trailer(AVFormatContext *s) > avio_write_marker(s->pb, AV_NOPTS_VALUE, > AVIO_DATA_MARKER_TRAILER); > mov_write_mfra_tag(pb, mov); > } > - } else { > + } else if (!(mov->flags & FF_MOV_FLAG_SKIP_TRAILER)) { > avio_write_marker(s->pb, AV_NOPTS_VALUE, > AVIO_DATA_MARKER_TRAILER); > mov_write_mfra_tag(pb, mov); > } > diff --git a/libavformat/movenc.h b/libavformat/movenc.h > index 6c922fb..f4ed188 100644 > --- a/libavformat/movenc.h > +++ b/libavformat/movenc.h > @@ -194,6 +194,7 @@ typedef struct MOVMuxContext { > #define FF_MOV_FLAG_FRAG_DISCONT (1 << 12) > #define FF_MOV_FLAG_DELAY_MOOV (1 << 13) > #define FF_MOV_FLAG_GLOBAL_SIDX (1 << 14) > +#define FF_MOV_FLAG_SKIP_TRAILER (1 << 15) > > int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt);
I think this is ok (and useful!) -- Vittorio _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
