[FFmpeg-devel] [PATCH] avcodec/pngdec: use correct frame for none disposition

[Carl Eugen Hoyos]

Am So., 14. Feb. 2021 um 17:10 Uhr schrieb Paul B Mahol <onemda at gmail.com>:
>
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  libavcodec/pngdec.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
> index 61642b7cbe..f0e2a0cad4 100644
> --- a/libavcodec/pngdec.c
> +++ b/libavcodec/pngdec.c
> @@ -1090,8 +1090,8 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
>
>
>      // Do the disposal operation specified by the last frame on the frame
> +    ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
>      if (s->last_dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
> -        ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
>          memcpy(buffer, s->last_picture.f->data[0], s->image_linesize * s->height);
>
>          if (s->last_dispose_op == APNG_DISPOSE_OP_BACKGROUND)
> @@ -1101,8 +1101,7 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
>          memcpy(s->previous_picture.f->data[0], buffer, s->image_linesize * s->height);
>          ff_thread_report_progress(&s->previous_picture, INT_MAX, 0);
>      } else {
> -        ff_thread_await_progress(&s->previous_picture, INT_MAX, 0);
> -        memcpy(buffer, s->previous_picture.f->data[0], s->image_linesize * s->height);
> +        memcpy(buffer, s->last_picture.f->data[0], s->image_linesize * s->height);

Please mention ticket #9017, there is no way to understand where this
comes from.

Thank you for looking into this, Carl Eugen