[FFmpeg-devel] [PATCH] lavfi: add duration field to AVFilterBufferRef

[Nicolas George]

Le tridi 13 thermidor, an CCXX, Stefano Sabatini a écrit :
> ---
>  libavfilter/audio.c       |    1 +
>  libavfilter/avcodec.c     |    2 ++
>  libavfilter/avfilter.h    |    7 +++++++
>  libavfilter/buffer.c      |    1 +
>  libavfilter/f_settb.c     |   10 ++++++----
>  libavfilter/vf_showinfo.c |    6 ++++--
>  6 files changed, 21 insertions(+), 6 deletions(-)

I must say, after some thought since last time it was suggested, I am not
completely sure it is such a good idea.

What happens with filters such as select? Is it supposed to wait for the
next accepted frame in order to adjust the duration?

And what if the duration and the next timestamp are inconsistent?

This is not an easy issue.

> 
> diff --git a/libavfilter/audio.c b/libavfilter/audio.c
> index f3eebbf..16d0d32 100644
> --- a/libavfilter/audio.c
> +++ b/libavfilter/audio.c
> @@ -179,6 +179,7 @@ int ff_filter_samples_framed(AVFilterLink *link, AVFilterBufferRef *samplesref)
>          buf_out = ff_default_get_audio_buffer(link, dst->min_perms,
>                                                samplesref->audio->nb_samples);
>          buf_out->pts                = samplesref->pts;
> +        buf_out->duration           = samplesref->duration;
>          buf_out->audio->sample_rate = samplesref->audio->sample_rate;
>  
>          /* Copy actual data into new samples buffer */
> diff --git a/libavfilter/avcodec.c b/libavfilter/avcodec.c
> index 8d61fbc..8ab1123 100644
> --- a/libavfilter/avcodec.c
> +++ b/libavfilter/avcodec.c
> @@ -32,6 +32,7 @@ int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src)
>      dst->pts    = src->pts;
>      dst->pos    = av_frame_get_pkt_pos(src);
>      dst->format = src->format;
> +    dst->duration = av_frame_get_pkt_duration(src);
>  
>      switch (dst->type) {
>      case AVMEDIA_TYPE_VIDEO:
> @@ -110,6 +111,7 @@ int avfilter_copy_buf_props(AVFrame *dst, const AVFilterBufferRef *src)
>      dst->pts     = src->pts;
>      dst->format  = src->format;
>      av_frame_set_pkt_pos(dst, src->pos);
> +    av_frame_set_pkt_duration(dst, src->duration);
>  
>      switch (src->type) {
>      case AVMEDIA_TYPE_VIDEO:
> diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
> index b7155a0..772d811 100644
> --- a/libavfilter/avfilter.h
> +++ b/libavfilter/avfilter.h
> @@ -174,6 +174,13 @@ typedef struct AVFilterBufferRef {
>      int perms;                  ///< permissions, see the AV_PERM_* flags
>  
>      enum AVMediaType type;      ///< media type of buffer data
> +
> +    /**
> +     * duration timestamp. The time unit may change during filtering,
> +     * as it is specified in the link and the filter code may need to
> +     * rescale the duration accordingly.

Missing required information: is it mandatory? If not, what is the value to
mean "unspecified"? AV_NOPTS_VALUE? 0?

> +     */
> +    int64_t duration;
>  } AVFilterBufferRef;
>  
>  /**
> diff --git a/libavfilter/buffer.c b/libavfilter/buffer.c
> index 30663b5..abb1659 100644
> --- a/libavfilter/buffer.c
> +++ b/libavfilter/buffer.c
> @@ -170,6 +170,7 @@ void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *s
>      // copy common properties
>      dst->pts             = src->pts;
>      dst->pos             = src->pos;
> +    dst->duration        = src->duration;
>  
>      switch (src->type) {
>      case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;
> diff --git a/libavfilter/f_settb.c b/libavfilter/f_settb.c
> index ff93f1e..16185d8 100644
> --- a/libavfilter/f_settb.c
> +++ b/libavfilter/f_settb.c
> @@ -102,12 +102,14 @@ static int config_output_props(AVFilterLink *outlink)
>  inline static void rescale_ref_time(AVFilterBufferRef *ref,
>                                      AVRational outtb, AVRational intb, void *log_ctx)
>  {
> -    int64_t orig_pts = ref->pts;
> +    int64_t orig_pts = ref->pts, orig_duration = ref->duration;
>      ref->pts = av_rescale_q(ref->pts, intb, outtb);
> +    ref->duration = av_rescale_q(ref->duration, intb, outtb);
>      av_log(log_ctx, AV_LOG_DEBUG,
> -           "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
> -           intb .num, intb .den, orig_pts,
> -           outtb.num, outtb.den, ref->pts);
> +           "tb:%d/%d pts:%"PRId64" duration:%"PRId64" -> "
> +           "tb:%d/%d pts:%"PRId64" duration:%"PRId64"\n",
> +           intb .num, intb .den, orig_pts, orig_duration,
> +           outtb.num, outtb.den, ref->pts, ref->duration);
>  }
>  
>  static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
> diff --git a/libavfilter/vf_showinfo.c b/libavfilter/vf_showinfo.c
> index 1c65563..d79105b 100644
> --- a/libavfilter/vf_showinfo.c
> +++ b/libavfilter/vf_showinfo.c
> @@ -62,11 +62,13 @@ static int end_frame(AVFilterLink *inlink)
>      }
>  
>      av_log(ctx, AV_LOG_INFO,
> -           "n:%d pts:%s pts_time:%s pos:%"PRId64" "
> +           "n:%d pts:%s pts_time:%s dur:%"PRId64" dur_time:%s pos:%"PRId64" "
>             "fmt:%s sar:%d/%d s:%dx%d i:%c iskey:%d type:%c "
>             "checksum:%08X plane_checksum:[%08X",
>             showinfo->frame,
> -           av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base), picref->pos,
> +           av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base),
> +           picref->duration, av_ts2timestr(picref->duration, &inlink->time_base),
> +           picref->pos,
>             av_pix_fmt_descriptors[picref->format].name,
>             picref->video->sample_aspect_ratio.num, picref->video->sample_aspect_ratio.den,
>             picref->video->w, picref->video->h,

Regards,

-- 
  Nicolas George
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