[FFmpeg-devel] [PATCH V2 2/3] libavcodec/vaapi_encode: Change the way to call async to increase performance

Chen, Wenbin wenbin.chen at intel.com
Wed Jan 5 09:59:25 EET 2022


> Wenbin Chen:
> > Fix: #7706. After commit 5fdcf85bbffe7451c2, vaapi encoder's performance
> > decrease. The reason is that vaRenderPicture() and vaSyncBuffer() are
> > called at the same time (vaRenderPicture() always followed by a
> > vaSyncBuffer()). 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.
> >
> > This change fits vaSyncBuffer(), so if driver does not support
> > vaSyncBuffer, it will keep previous operation.
> >
> > Signed-off-by: Wenbin Chen <wenbin.chen at intel.com>
> > ---
> >  libavcodec/vaapi_encode.c | 64 ++++++++++++++++++++++++++++++++-----
> --
> >  libavcodec/vaapi_encode.h |  5 +++
> >  2 files changed, 58 insertions(+), 11 deletions(-)
> >
> > diff --git a/libavcodec/vaapi_encode.c b/libavcodec/vaapi_encode.c
> > index b87b58a42b..9a3b3ba4ad 100644
> > --- a/libavcodec/vaapi_encode.c
> > +++ b/libavcodec/vaapi_encode.c
> > @@ -984,8 +984,10 @@ 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) {
> > @@ -1210,18 +1212,45 @@ 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);
> > +#if VA_CHECK_VERSION(1, 9, 0)
> > +    if (ctx->has_sync_buffer_func) {
> > +        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 +
> > +                (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;
> > +            }
> > +            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;
> > +    } else
> > +#endif
> > +    {
> > +        pic = NULL;
> > +        err = vaapi_encode_pick_next(avctx, &pic);
> > +        if (err < 0)
> > +            return err;
> > +        av_assert0(pic);
> >
> > -    pic->encode_order = ctx->encode_order++;
> > +        pic->encode_order = ctx->encode_order++;
> >
> > -    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;
> > +        }
> >      }
> >
> >      err = vaapi_encode_output(avctx, pic, pkt);
> > @@ -2555,6 +2584,18 @@ av_cold int
> ff_vaapi_encode_init(AVCodecContext *avctx)
> >          }
> >      }
> >
> > +#if VA_CHECK_VERSION(1, 9, 0)
> > +    //check vaSyncBuffer function
> > +    vas = vaSyncBuffer(ctx->hwctx->display, 0, 0);
> > +    if (vas != VA_STATUS_ERROR_UNIMPLEMENTED) {
> > +        ctx->has_sync_buffer_func = 1;
> > +        ctx->encode_fifo = av_fifo_alloc((MAX_PICTURE_REFERENCES + 1) *
> > +                                        sizeof(VAAPIEncodePicture *));
> > +        if (!ctx->encode_fifo)
> > +            return AVERROR(ENOMEM);
> > +    }
> > +#endif
> > +
> >      return 0;
> >
> >  fail:
> > @@ -2592,6 +2633,7 @@ 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);
> 
> Is it guaranteed that the fifo is empty at this point? I don't think so.

I don't check the fifo size, because in ff_vaapi_encode_close() all pics
are already freed and encode_fifo only buffer pic.
```
    for (pic = ctx->pic_start; pic; pic = next) {
        next = pic->next;
        vaapi_encode_free(avctx, pic);
    }
```

> 
> >
> >      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..560a1c42a9 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 +346,10 @@ typedef struct VAAPIEncodeContext {
> >      int             roi_warned;
> >
> >      AVFrame         *frame;
> > +    //Store buffered pic
> > +    AVFifoBuffer *encode_fifo;
> > +    //Whether the driver support vaSyncBuffer
> > +    int has_sync_buffer_func;
> >  } VAAPIEncodeContext;
> >
> >  enum {
> >
> 
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