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

[Jeyapal, Karthick]

On 6/22/20 2:13 AM, Przemysław Sobala wrote:
>
> 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])?
Pushed, Thanks.
Just to let you know, as per the ffmpeg policy I had to wait for atleast 3 days after the latest patch posting(17-June), before it can be pushed to the master.
Since in this case the 3 day wait period ended on a weekend there was some additional delay. Sorry for any inconvenience caused.
>
> --
> regards
> Przemysław Sobala