[mythtv] FFmpeg 4.4.1 problems

[Piotr Oniszczuk]

> Wiadomość napisana przez Klaas de Waal <klaas.de.waal at gmail.com> w dniu 24.11.2021, o godz. 21:55:
> 
> The cause for the blocking artifacts with VDPAU playback start and skipping is the following commit in release 4.4 of ffmpeg:
> 
> [klaas at modu ffmpeg]$ git show 99042c2bf6
> commit 99042c2bf6cc79006036502a6abbec5e51f73673
> Author: James Almer <jamrial at gmail.com>
> Date:   Mon Mar 8 23:10:10 2021 -0300
> 
>     avcodec/h264_slice: don't copy frame data during error concealment
> 
>     In addition to the fact that av_image_copy() cannot handle hardware pixel formats,
>     h->short_ref[0]->f may not be writable at this point.
> 
>     Based on a patch by Hendrik Leppkes.
> 
>     Signed-off-by: James Almer <jamrial at gmail.com>
> 
> diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
> index fa7a639053..14b945756b 100644
> --- a/libavcodec/h264_slice.c
> +++ b/libavcodec/h264_slice.c
> @@ -1599,14 +1599,15 @@ static int h264_field_start(H264Context *h, const H264SliceContext *sl,
>                  ff_thread_await_progress(&prev->tf, INT_MAX, 0);
>                  if (prev->field_picture)
>                      ff_thread_await_progress(&prev->tf, INT_MAX, 1);
> -                av_image_copy(h->short_ref[0]->f->data,
> -                              h->short_ref[0]->f->linesize,
> -                              (const uint8_t **)prev->f->data,
> -                              prev->f->linesize,
> -                              prev->f->format,
> -                              prev->f->width,
> -                              prev->f->height);
> +                ff_thread_release_buffer(h->avctx, &h->short_ref[0]->tf);
> +                h->short_ref[0]->tf.f = h->short_ref[0]->f;
> +                ret = ff_thread_ref_frame(&h->short_ref[0]->tf, &prev->tf);
> +                if (ret < 0)
> +                    return ret;
>                  h->short_ref[0]->poc = prev->poc + 2U;
> +                ff_thread_report_progress(&h->short_ref[0]->tf, INT_MAX, 0);
> +                if (h->short_ref[0]->field_picture)
> +                    ff_thread_report_progress(&h->short_ref[0]->tf, INT_MAX, 1);
>              } else if (!h->frame_recovered && !h->avctx->hwaccel)
>                  ff_color_frame(h->short_ref[0]->f, c);
>              h->short_ref[0]->frame_num = h->poc.prev_frame_num;
> 
> 
> The attached patch reverses the above commit and can be applied to the devel/ffmpeg-resync branch.
> 
> Klaas.
> 

Klaas

Fantastic work !