[FFmpeg-devel] [PATCH 1/3] libavcodec/vaapi_encode: Change the way to call async to increase performance

[Chen, Wenbin]

> On Wed, 2021-10-27 at 16:57 +0800, Wenbin Chen wrote:
> > Fix: #7706. After commit 5fdcf85bbffe7451c2, vaapi encoder's performance
> > decrease. The reason is that vaRenderPicture() and vaSyncSurface() are
> > called at the same time (vaRenderPicture() always followed by a
> > vaSyncSurface()). When we encode stream with B frames, we need buffer
> to
> > reorder frames, so we can send serveral frames to HW at once to increase
> > performance. Now I changed them to be called in a
> > asynchronous way, which will make better use of hardware.
> > 1080p transcoding increases about 17% fps on my environment.
> 
> Could you provide your command ? I'd like to have a try.
> 
> Thanks
> Haihao

Here is my command:
ffmpeg -hwaccel vaapi -hwaccel_output_format vaapi -i input.264 -c:v h264_vaapi output.264

Thanks
Wenbin

> 
> >
> > Signed-off-by: Wenbin Chen <wenbin.chen at intel.com>
> > ---
> >  libavcodec/vaapi_encode.c | 41 ++++++++++++++++++++++++++++-----------
> >  libavcodec/vaapi_encode.h |  3 +++
> >  2 files changed, 33 insertions(+), 11 deletions(-)
> >
> > diff --git a/libavcodec/vaapi_encode.c b/libavcodec/vaapi_encode.c
> > index ec054ae701..5927849233 100644
> > --- a/libavcodec/vaapi_encode.c
> > +++ b/libavcodec/vaapi_encode.c
> > @@ -951,8 +951,10 @@ static int
> vaapi_encode_pick_next(AVCodecContext *avctx,
> >      if (!pic && ctx->end_of_stream) {
> >          --b_counter;
> >          pic = ctx->pic_end;
> > -        if (pic->encode_issued)
> > +        if (pic->encode_complete)
> >              return AVERROR_EOF;
> > +        else if (pic->encode_issued)
> > +            return AVERROR(EAGAIN);
> >      }
> >
> >      if (!pic) {
> > @@ -1177,20 +1179,31 @@ int
> ff_vaapi_encode_receive_packet(AVCodecContext
> > *avctx, AVPacket *pkt)
> >              return AVERROR(EAGAIN);
> >      }
> >
> > -    pic = NULL;
> > -    err = vaapi_encode_pick_next(avctx, &pic);
> > -    if (err < 0)
> > -        return err;
> > -    av_assert0(pic);
> > +    while (av_fifo_size(ctx->encode_fifo) <= MAX_PICTURE_REFERENCES *
> > sizeof(VAAPIEncodePicture *)) {
> > +        pic = NULL;
> > +        err = vaapi_encode_pick_next(avctx, &pic);
> > +        if (err < 0)
> > +            break;
> > +        av_assert0(pic);
> >
> > -    pic->encode_order = ctx->encode_order++;
> > +        pic->encode_order = ctx->encode_order +
> > +                            (av_fifo_size(ctx->encode_fifo) /
> > sizeof(VAAPIEncodePicture *));
> >
> > -    err = vaapi_encode_issue(avctx, pic);
> > -    if (err < 0) {
> > -        av_log(avctx, AV_LOG_ERROR, "Encode failed: %d.\n", err);
> > -        return err;
> > +        err = vaapi_encode_issue(avctx, pic);
> > +        if (err < 0) {
> > +            av_log(avctx, AV_LOG_ERROR, "Encode failed: %d.\n", err);
> > +            return err;
> > +        }
> > +
> > +        av_fifo_generic_write(ctx->encode_fifo, &pic, sizeof(pic), NULL);
> >      }
> >
> > +    if (!av_fifo_size(ctx->encode_fifo))
> > +        return err;
> > +
> > +    av_fifo_generic_read(ctx->encode_fifo, &pic, sizeof(pic), NULL);
> > +    ctx->encode_order = pic->encode_order + 1;
> > +
> >      err = vaapi_encode_output(avctx, pic, pkt);
> >      if (err < 0) {
> >          av_log(avctx, AV_LOG_ERROR, "Output failed: %d.\n", err);
> > @@ -2520,6 +2533,11 @@ av_cold int
> ff_vaapi_encode_init(AVCodecContext *avctx)
> >          }
> >      }
> >
> > +    ctx->encode_fifo = av_fifo_alloc((MAX_PICTURE_REFERENCES + 1) *
> > +                                      sizeof(VAAPIEncodePicture *));
> > +    if (!ctx->encode_fifo)
> > +        return AVERROR(ENOMEM);
> > +
> >      return 0;
> >
> >  fail:
> > @@ -2552,6 +2570,7 @@ av_cold int
> ff_vaapi_encode_close(AVCodecContext *avctx)
> >
> >      av_freep(&ctx->codec_sequence_params);
> >      av_freep(&ctx->codec_picture_params);
> > +    av_fifo_freep(&ctx->encode_fifo);
> >
> >      av_buffer_unref(&ctx->recon_frames_ref);
> >      av_buffer_unref(&ctx->input_frames_ref);
> > diff --git a/libavcodec/vaapi_encode.h b/libavcodec/vaapi_encode.h
> > index b41604a883..89fe8de466 100644
> > --- a/libavcodec/vaapi_encode.h
> > +++ b/libavcodec/vaapi_encode.h
> > @@ -29,6 +29,7 @@
> >
> >  #include "libavutil/hwcontext.h"
> >  #include "libavutil/hwcontext_vaapi.h"
> > +#include "libavutil/fifo.h"
> >
> >  #include "avcodec.h"
> >  #include "hwconfig.h"
> > @@ -345,6 +346,8 @@ typedef struct VAAPIEncodeContext {
> >      int             roi_warned;
> >
> >      AVFrame         *frame;
> > +
> > +    AVFifoBuffer *encode_fifo;
> >  } VAAPIEncodeContext;
> >
> >  enum {