[FFmpeg-devel] [PATCH 2/2] avformat/dashenc: Calculate average bitrate for adaptation sets in static manifest

[Przemysław Sobala]

On Wed, Jun 17, 2020 at 1:58 PM Jeyapal, Karthick <kjeyapal at akamai.com>
wrote:

>
> On 6/17/20 5:20 PM, Przemysław Sobala wrote:
> > If stream's bitrate is not specified:
> > - for static manifest: an average bitrate will be calculated and used,
> > - for dynamic manifest: first segment's bitrate will be calculated and
> used, as before,
> > for bandwidth setting in adaptation sets.
> > ---
> >  libavformat/dashenc.c | 24 ++++++++++++++++--------
> >  1 file changed, 16 insertions(+), 8 deletions(-)
> >
> > diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
> > index 05deb5c1b5..62193058d7 100644
> > --- a/libavformat/dashenc.c
> > +++ b/libavformat/dashenc.c
> > @@ -115,6 +115,7 @@ typedef struct OutputStream {
> >      int64_t last_dts, last_pts;
> >      int last_flags;
> >      int bit_rate;
> > +    int first_segment_bit_rate;
> >      SegmentType segment_type;  /* segment type selected for this
> particular stream */
> >      const char *format_name;
> >      const char *extension_name;
> > @@ -840,8 +841,12 @@ static int write_adaptation_set(AVFormatContext *s,
> AVIOContext *out, int as_ind
> >              continue;
> >
> >          if (os->bit_rate > 0)
> > -            snprintf(bandwidth_str, sizeof(bandwidth_str), "
> bandwidth=\"%d\"",
> > -                     os->bit_rate);
> > +            snprintf(bandwidth_str, sizeof(bandwidth_str), "
> bandwidth=\"%d\"", os->bit_rate);
> > +        else if (final) {
> > +            int average_bit_rate = os->pos * 8 * AV_TIME_BASE /
> c->total_duration;
> > +            snprintf(bandwidth_str, sizeof(bandwidth_str), "
> bandwidth=\"%d\"", average_bit_rate);
> > +        } else if (os->first_segment_bit_rate > 0)
> > +            snprintf(bandwidth_str, sizeof(bandwidth_str), "
> bandwidth=\"%d\"", os->first_segment_bit_rate);
> >
> >          if (as->media_type == AVMEDIA_TYPE_VIDEO) {
> >              avio_printf(out, "\t\t\t<Representation id=\"%d\"
> mimeType=\"video/%s\" codecs=\"%s\"%s width=\"%d\" height=\"%d\"",
> > @@ -1305,7 +1310,13 @@ static int write_manifest(AVFormatContext *s, int
> final)
> >              OutputStream *os = &c->streams[i];
> >              char *agroup = NULL;
> >              char *codec_str_ptr = NULL;
> > -            int stream_bitrate = st->codecpar->bit_rate +
> os->muxer_overhead;
> > +            int stream_bitrate = os->muxer_overhead;
> > +            if (os->bit_rate > 0)
> > +                stream_bitrate += os->bit_rate;
> > +            else if (final)
> > +                stream_bitrate += os->pos * 8 * AV_TIME_BASE /
> c->total_duration;
> > +            else if (os->first_segment_bit_rate > 0)
> > +                stream_bitrate += os->first_segment_bit_rate;
> >              if (st->codecpar->codec_type != AVMEDIA_TYPE_VIDEO)
> >                  continue;
> >              if (os->segment_type != SEGMENT_TYPE_MP4)
> > @@ -1958,11 +1969,8 @@ static int dash_flush(AVFormatContext *s, int
> final, int stream)
> >          os->total_pkt_size = 0;
> >          os->total_pkt_duration = 0;
> >
> > -        if (!os->bit_rate) {
> > -            // calculate average bitrate of first segment
> > -            int64_t bitrate = (int64_t) range_length * 8 * AV_TIME_BASE
> / duration;
> > -            if (bitrate >= 0)
> > -                os->bit_rate = bitrate;
> > +        if (!os->bit_rate && !os->first_segment_bit_rate) {
> > +            os->first_segment_bit_rate = (int64_t) range_length * 8 *
> AV_TIME_BASE / duration;
> >          }
> >          add_segment(os, os->filename, os->start_pts, os->max_pts -
> os->start_pts, os->pos, range_length, index_length, next_exp_index);
> >          av_log(s, AV_LOG_VERBOSE, "Representation %d media segment %d
> written to: %s\n", i, os->segment_index, os->full_path);
> LGTM. Thanks.
>

Can it be merged then (along with [PATCH 1/2])?

--
regards
Przemysław Sobala