Re: [FFmpeg-devel] [PATCH] Fixed PNG decoding with Paeth filter for RGBA 64-bits.

2014-12-08 Thread Dominique Leroux 
Hi Michael,

Yes, this does fix the issues I saw with RGBA64.

Thanks,

Dominique

-Original Message-
From: Michael Niedermayer [mailto:michae...@gmx.at] 
Sent: Sunday, December 07, 2014 6:55 AM
To: FFmpeg development discussions and patches
Cc: Dominique Leroux
Subject: Re: [FFmpeg-devel] [PATCH] Fixed PNG decoding with Paeth filter for 
RGBA 64-bits.

Hi

On Sun, Dec 07, 2014 at 05:39:16AM +0100, Michael Niedermayer wrote:
[...]
> >  Changelog|  1 +
> >  libavcodec/pngdec.c  | 16 
> >  libavcodec/pngdsp.c  |  7 +--
> >  libavcodec/pngdsp.h  |  5 +
> >  libavcodec/x86/pngdsp_init.c | 17 +++--
> >  5 files changed, 34 insertions(+), 12 deletions(-)
> 
> this is not correct
> iam a bit tired so i just quickly read your elaborate text but the asm 
> works in steps of bpp not steps of 4 and writes 4 bytes at a time you 
> seem to assume the asm is simpler and more systematic than it actually 
> is, also theres are bugs in the asm i think ive a fix for some of this 
> locally but id like to test it more before pushing

patchset posted, please take a look and review / check / confirm if this fixes 
all issues you saw

Thanks

[...]

-- 
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many things microsoft did are stupid, but not doing something just because 
microsoft did it is even more stupid. If everything ms did were stupid they 
would be bankrupt already.
___
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel

Re: [FFmpeg-devel] [PATCH] Fixed PNG decoding with Paeth filter for RGBA 64-bits.

2014-12-05 Thread Dominique Leroux 
Hi Cristophe,

Before submitting yesterday evening, I pulled the latest changes from master 
and the problem is still present.

My situation happens with RGBA64.  The structure of the existing C code was 
meant to enter the optimized path with a buffer size that is compatible with 
SIMD constraints.  So I just generalized the buffer resizing so it takes any 
bpp into account (and not just bpp=3 or bpp=4 like before).

Here are sample files that are 4 lines long: the original and the corrupted 
output.  The corruption is on the rightmost edge, where last 3 lines have the 
expected pink replaced by yellow.

With my fix, the resulting output is as as the original.  The resulting file 
layout differs, however: the original has one single IDAT chunk for all 4 
lines, whereas the output files have one IDAT chunk per line (hence the bigger 
size).  Maybe this is part of the reason it went unnoticed for so long as I 
don't think it is possible to generate such a png file with ffmpeg and the 
corruption does not happen on the first line.

Thanks for looking at this,

Dominique

-Original Message-
From: ffmpeg-devel-boun...@ffmpeg.org [mailto:ffmpeg-devel-boun...@ffmpeg.org] 
On Behalf Of Christophe Gisquet
Sent: Friday, December 05, 2014 4:30 AM
To: FFmpeg development discussions and patches
Subject: Re: [FFmpeg-devel] [PATCH] Fixed PNG decoding with Paeth filter for 
RGBA 64-bits.

Hi,

2014-12-05 1:20 GMT+01:00 Dominique Leroux :
> Found and fixed an artifact in the last column of decoded RGBA 64-bits PNG 
> images.
>
> The code was dealing with a SIMD-optimized version of the function without 
> taking into account that we can have RGB/RGBA images that are respectively 6 
> or 8  bytes per pixel (not just 3 or 4).

First, what version are you working on? Ronald included a fix in 
http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=af79a0c48a41fd99b674b39ac509ae442974715d
that would then be incomplete?

If true, then it probably means we don't have a "fate" test for it (ie a means 
to validate ffmpeg's output against a known "good"
checksum/behaviour), or that it is unaffected by the bug.

In any case, could you share a sample file exhibiting the issue? I guess 
cropping to the last few lines would be fine from a quick glance at your patch. 
But I haven't studied the issue to actually validate it.

Thank you,
--
Christophe
___
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
___
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel

[FFmpeg-devel] [PATCH] Fixed PNG decoding with Paeth filter for RGBA 64-bits.

2014-12-04 Thread Dominique Leroux 
Found and fixed an artifact in the last column of decoded RGBA 64-bits PNG 
images.

The code was dealing with a SIMD-optimized version of the function without 
taking into account that we can have RGB/RGBA images that are respectively 6 or 
8  bytes per pixel (not just 3 or 4).

Dominique


0001-Fixed-PNG-decoding-with-Paeth-filter-for-RGBA-64-bit.patch
Description: 0001-Fixed-PNG-decoding-with-Paeth-filter-for-RGBA-64-bit.patch
___
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel