[x264-devel] Bug found in --intra-refresh

[Jason Garrett-Glaser]

On Mon, Jul 22, 2013 at 4:44 PM, Alain Champenois <achampen at matrox.com> wrote:
>
> The current --intra-refresh implementation in x264 has a hole which allow
> corruption to subsist even after a full 'frame refresh'. This problem can
> in some case leave important visual artifact (after a corruption of the
> stream occurred).
>
> I've included an example of the visual corruption that can subsist after a
> full 'frame refresh'. In this example, from the same x264 stream, the image
> to the left is the result of a normal decode, and the image to the right is
> the same frame decoded after the first IDR of the stream has been corrupted
> (and one full 'frame refresh' has completed).
>
> The hole is related to dct8x8 not being handled properly. In intra_refresh
> mode, the Intra column stop corruption from propagating from right to left
> because the 'top-right' Intra modes are disabled for the Intra columns.
> However in Intra 8x8 (with dct8x8 enabled), some top-right pixels are still
> used for the Intra prediction and therefore corruption to the right can
> propagate left, in and over the Intra columns.

Good catch. Would something like this work?

Jason
-------------- next part --------------
A non-text attachment was scrubbed...
Name: test.diff
Type: application/octet-stream
Size: 1814 bytes
Desc: not available
URL: <http://mailman.videolan.org/pipermail/x264-devel/attachments/20130722/f9d6173b/attachment.obj>