[FFmpeg-devel] [PATCH v3] avformat/movenc: Added an option to disable SIDX atom

[Andrey Semashev]

On 12/6/18 12:20 PM, Andrey Semashev wrote:
> On 12/6/18 8:07 AM, Karthick J wrote:
>> ---
>>   doc/muxers.texi      |  4 ++++
>>   libavformat/movenc.c | 12 ++++++++++--
>>   libavformat/movenc.h |  1 +
>>   3 files changed, 15 insertions(+), 2 deletions(-)
>>
>> diff --git a/doc/muxers.texi b/doc/muxers.texi
>> index f1cc6f5fee..ca10741900 100644
>> --- a/doc/muxers.texi
>> +++ b/doc/muxers.texi
>> @@ -1325,6 +1325,10 @@ more efficient), but with this option set, the 
>> muxer writes one moof/mdat
>>   pair for each track, making it easier to separate tracks.
>>   This option is implicitly set when writing ismv (Smooth Streaming) 
>> files.
>> + at item -movflags skip_sidx
>> +Skip writing of sidx atom. When bitrate overhead due to sidx atom is 
>> high,
>> +this option could be used for cases where sidx atom is not mandatory.
>> +When global_sidx flag is enabled, this option will be ignored.
>>   @item -movflags faststart
>>   Run a second pass moving the index (moov atom) to the beginning of 
>> the file.
>>   This operation can take a while, and will not work in various 
>> situations such
>> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
>> index 6dab5193b0..2f7755bf69 100644
>> --- a/libavformat/movenc.c
>> +++ b/libavformat/movenc.c
>> @@ -75,6 +75,7 @@ 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_sidx", "Skip writing of sidx atom", 0, AV_OPT_TYPE_CONST, 
>> {.i64 = FF_MOV_FLAG_SKIP_SIDX}, INT_MIN, INT_MAX, 
>> AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
>>       { "write_colr", "Write colr atom (Experimental, may be renamed 
>> or changed, do not use from scripts)", 0, AV_OPT_TYPE_CONST, {.i64 = 
>> FF_MOV_FLAG_WRITE_COLR}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, 
>> "movflags" },
>>       { "write_gama", "Write deprecated gama atom", 0, 
>> AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_WRITE_GAMA}, INT_MIN, INT_MAX, 
>> AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
>>       { "use_metadata_tags", "Use mdta atom for metadata.", 0, 
>> AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_USE_MDTA}, INT_MIN, INT_MAX, 
>> AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
>> @@ -4603,7 +4604,8 @@ static int mov_write_moof_tag(AVIOContext *pb, 
>> MOVMuxContext *mov, int tracks,
>>       mov_write_moof_tag_internal(avio_buf, mov, tracks, 0);
>>       moof_size = ffio_close_null_buf(avio_buf);
>> -    if (mov->flags & FF_MOV_FLAG_DASH && !(mov->flags & 
>> FF_MOV_FLAG_GLOBAL_SIDX))
>> +    if (mov->flags & FF_MOV_FLAG_DASH &&
>> +        !(mov->flags & (FF_MOV_FLAG_GLOBAL_SIDX | 
>> FF_MOV_FLAG_SKIP_SIDX)))
>>           mov_write_sidx_tags(pb, mov, tracks, moof_size + 8 + 
>> mdat_size);
>>       if (mov->write_prft > MOV_PRFT_NONE && mov->write_prft < 
>> MOV_PRFT_NB)
>> @@ -5422,7 +5424,8 @@ int ff_mov_write_packet(AVFormatContext *s, 
>> AVPacket *pkt)
>>                * the next fragment. This means the cts of the first 
>> sample must
>>                * be the same in all fragments, unless end_pts was 
>> updated by
>>                * the packet causing the fragment to be written. */
>> -            if ((mov->flags & FF_MOV_FLAG_DASH && !(mov->flags & 
>> FF_MOV_FLAG_GLOBAL_SIDX)) ||
>> +            if ((mov->flags & FF_MOV_FLAG_DASH &&
>> +                !(mov->flags & (FF_MOV_FLAG_GLOBAL_SIDX | 
>> FF_MOV_FLAG_SKIP_SIDX))) ||
>>                   mov->mode == MODE_ISM)
>>                   pkt->pts = pkt->dts + trk->end_pts - 
>> trk->cluster[trk->entry].dts;
>>           } else {
>> @@ -6067,6 +6070,11 @@ static int mov_init(AVFormatContext *s)
>>           s->flags &= ~AVFMT_FLAG_AUTO_BSF;
>>       }
>> +    if (mov->flags & FF_MOV_FLAG_GLOBAL_SIDX && s->flags & 
>> FF_MOV_FLAG_SKIP_SIDX) {
> 
> s->flags here should be mov->flags as well.

Sorry, didn't read the later messages.

>> +        av_log(s, AV_LOG_WARNING, "Global SIDX enabled; Ignoring 
>> skip_sidx option\n");
>> +        mov->flags &= ~FF_MOV_FLAG_SKIP_SIDX;
>> +    }
>> +
>>       if (mov->flags & FF_MOV_FLAG_FASTSTART) {
>>           mov->reserved_moov_size = -1;
>>       }
>> diff --git a/libavformat/movenc.h b/libavformat/movenc.h
>> index fe605d1ad2..68d6f23a5a 100644
>> --- a/libavformat/movenc.h
>> +++ b/libavformat/movenc.h
>> @@ -257,6 +257,7 @@ typedef struct MOVMuxContext {
>>   #define FF_MOV_FLAG_SKIP_TRAILER          (1 << 18)
>>   #define FF_MOV_FLAG_NEGATIVE_CTS_OFFSETS  (1 << 19)
>>   #define FF_MOV_FLAG_FRAG_EVERY_FRAME      (1 << 20)
>> +#define FF_MOV_FLAG_SKIP_SIDX             (1 << 21)
>>   int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt);
>>
>