[FFmpeg-devel] [PATCH]lavc/proresdec2: Fix slice_count for very high resolutions

[Michael Niedermayer]

On Sun, Oct 25, 2015 at 03:09:24PM +0100, Carl Eugen Hoyos wrote:
> On Sunday 25 October 2015 01:37:15 pm Carl Eugen Hoyos wrote:
> > Hi!
> >
> > Attached patch intends to fix an issue reported by forum user Koracas:
> > For slice_count > 0x10000 FFmpeg fails to decode a frame, QT seems to
> > ignore the value.
> 
> New patch attached.
> 
> Please comment, Carl Eugen

>  proresdec2.c |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 9f0961894862a1ff8a0ce9e3f8f0bfbf3f1ee15d  patchslicecount.diff
> diff --git a/libavcodec/proresdec2.c b/libavcodec/proresdec2.c
> index 932f85f..2d47a13 100644
> --- a/libavcodec/proresdec2.c
> +++ b/libavcodec/proresdec2.c
> @@ -180,7 +180,10 @@ static int decode_picture_header(AVCodecContext *avctx, const uint8_t *buf, cons
>      else
>          ctx->mb_height = (avctx->height + 15) >> 4;
>  
> -    slice_count = AV_RB16(buf + 5);
> +    // QT ignores the written value
> +    // slice_count = AV_RB16(buf + 5);
> +    slice_count = ctx->mb_height * ((ctx->mb_width >> log2_slice_mb_width) +
> +                                    av_popcount(ctx->mb_width & (1 << log2_slice_mb_width) - 1));

if thats what QT does then sure LGTM

[...]

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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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