[FFmpeg-devel] [PATCH 3/4] fftools/ffmpeg: support variable dimension encode

[Fu, Linjie]

> -----Original Message-----
> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of James Almer
> Sent: Tuesday, July 30, 2019 00:44
> To: ffmpeg-devel at ffmpeg.org
> Subject: Re: [FFmpeg-devel] [PATCH 3/4] fftools/ffmpeg: support variable
> dimension encode
> 
> On 7/29/2019 11:44 AM, Linjie Fu wrote:
> > Flush encoders when dimension change happens, reset draining to resume
> > encode.
> >
> > If encoder doesn't support variable dimension, stop encoding and
> > report errors.
> >
> > Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> > ---
> >  fftools/ffmpeg.c    | 13 +++++++++++++
> >  libavcodec/encode.c |  4 ++++
> >  2 files changed, 17 insertions(+)
> >
> > diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> > index 5d52430..8ceeaaa 100644
> > --- a/fftools/ffmpeg.c
> > +++ b/fftools/ffmpeg.c
> > @@ -130,6 +130,7 @@ static void do_video_stats(OutputStream *ost, int
> frame_size);
> >  static BenchmarkTimeStamps get_benchmark_time_stamps(void);
> >  static int64_t getmaxrss(void);
> >  static int ifilter_has_all_input_formats(FilterGraph *fg);
> > +static void flush_encoders(void);
> >
> >  static int run_as_daemon  = 0;
> >  static int nb_frames_dup = 0;
> > @@ -1067,6 +1068,18 @@ static void do_video_out(OutputFile *of,
> >      InputStream *ist = NULL;
> >      AVFilterContext *filter = ost->filter->filter;
> >
> > +    /* flush encoders in dynamic resolution encode */
> > +    if (next_picture && (enc->width != next_picture->width ||
> > +                         enc->height != next_picture->height)) {
> > +        flush_encoders();
> > +
> > +        if (!(enc->codec->capabilities &
> AV_CODEC_CAP_VARIABLE_DIMENSIONS)) {
> > +            av_log(NULL, AV_LOG_ERROR, "Dynamic resolution encode "
> > +                            "is not supported by %s.\n", enc->codec->name);
> > +            goto error;
> > +        }
> > +    }
> > +
> >      if (ost->source_index >= 0)
> >          ist = input_streams[ost->source_index];
> >
> > diff --git a/libavcodec/encode.c b/libavcodec/encode.c
> > index d12c425..9303bc9 100644
> > --- a/libavcodec/encode.c
> > +++ b/libavcodec/encode.c
> > @@ -389,6 +389,10 @@ int attribute_align_arg
> avcodec_send_frame(AVCodecContext *avctx, const AVFrame
> >      if (!avcodec_is_open(avctx) || !av_codec_is_encoder(avctx->codec))
> >          return AVERROR(EINVAL);
> >
> > +    /* reset draining when encoder is flushed in variable dimensions
> encoding */
> > +    if (frame)
> > +        avctx->internal->draining = 0;
> 
> This is an API change that can break some workflows.
> 
> avcodec_flush_buffers() is the public function meant to flush an
> AVCodecContext.
> 

Thanks for the hint, updated.

- linjie