[FFmpeg-devel] [PATCH 5/5] avformat/movenc: add support for AV1 streams

[James Almer]

On 7/12/2018 8:26 AM, Michael Niedermayer wrote:
> On Mon, Jul 09, 2018 at 03:26:54PM -0300, James Almer wrote:
>> Signed-off-by: James Almer <jamrial at gmail.com>
>> ---
>> ff_av1_filter_obus() could eventually be replaced by an autoinserted
>> filter_units bsf, assuming it doesn't slow down the muxing process
>> too much (CBS is fast reading packets, but not so much assembling and
>> writing packets).
>> ff_isom_write_av1c() however can't be replaced given filter_units
>> doesn't handle extradata (either codecpar or packet side data).
> [...]
>> +#endif /* AVFORMAT_AV1_H */
>> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
>> index fe0a244a8f..784df6d08d 100644
>> --- a/libavformat/movenc.c
>> +++ b/libavformat/movenc.c
>> @@ -30,6 +30,7 @@
>>  #include "riff.h"
>>  #include "avio.h"
>>  #include "isom.h"
>> +#include "av1.h"
>>  #include "avc.h"
>>  #include "libavcodec/ac3_parser_internal.h"
>>  #include "libavcodec/dnxhddata.h"
>> @@ -1163,6 +1164,19 @@ static int mov_write_d263_tag(AVIOContext *pb)
>>      return 0xf;
>>  }
>>  
>> +static int mov_write_av1c_tag(AVIOContext *pb, MOVTrack *track)
>> +{
>> +    int64_t pos = avio_tell(pb);
>> +
>> +    avio_wb32(pb, 0);
>> +    ffio_wfourcc(pb, "av1C");
>> +    avio_w8(pb, 0); /* version */
>> +    avio_wb24(pb, 0); /* flags */
>> +    avio_w8(pb, 0); /* reserved (3), initial_presentation_delay_present (1), initial_presentation_delay_minus_one/reserved (4) */
>> +    ff_isom_write_av1c(pb, track->vos_data, track->vos_len);
>> +    return update_size(pb, pos);
>> +}
>> +
>>  static int mov_write_avcc_tag(AVIOContext *pb, MOVTrack *track)
>>  {
>>      int64_t pos = avio_tell(pb);
>> @@ -2009,6 +2023,8 @@ static int mov_write_video_tag(AVIOContext *pb, MOVMuxContext *mov, MOVTrack *tr
>>              mov_write_uuid_tag_ipod(pb);
>>      } else if (track->par->codec_id == AV_CODEC_ID_VP9) {
>>          mov_write_vpcc_tag(mov->fc, pb, track);
>> +    } else if (track->par->codec_id == AV_CODEC_ID_AV1) {
>> +        mov_write_av1c_tag(pb, track);
>>      } else if (track->par->codec_id == AV_CODEC_ID_VC1 && track->vos_len > 0)
>>          mov_write_dvc1_tag(pb, track);
>>      else if (track->par->codec_id == AV_CODEC_ID_VP6F ||
>> @@ -5319,6 +5335,13 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
>>          } else {
>>              size = ff_hevc_annexb2mp4(pb, pkt->data, pkt->size, 0, NULL);
>>          }
>> +    } else if (par->codec_id == AV_CODEC_ID_AV1) {
>> +        if (trk->hint_track >= 0 && trk->hint_track < mov->nb_streams) {
>> +            ff_av1_filter_obus_buf(pkt->data, &reformatted_data, &size);
>> +            avio_write(pb, reformatted_data, size);
>> +        } else {
>> +            size = ff_av1_filter_obus(pb, pkt->data, pkt->size);
>> +        }
>>  #if CONFIG_AC3_PARSER
>>      } else if (par->codec_id == AV_CODEC_ID_EAC3) {
>>          size = handle_eac3(mov, pkt, trk);
> 
>> @@ -5438,7 +5461,7 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
>>          av_log(s, AV_LOG_WARNING, "pts has no value\n");
>>          pkt->pts = pkt->dts;
>>      }
>> -    if (pkt->dts != pkt->pts)
>> +    if (pkt->dts != pkt->pts && par->codec_id != AV_CODEC_ID_AV1)
> 
> When is dts != pts && par->codec_id == AV_CODEC_ID_AV1 ?
> 
> Iam asking because if it never is then this check is not needed
> and if it is sometimes true then i suspect the pts values will be lost
> that is the demuxer input would differ from the muxer output, which doesnt
> seem right
> Maybe iam missing something

It should never be. I just added this check for extra paranoid
precaution since the spec forbids the ctts box. I can remove it.