[FFmpeg-devel] [PATCH] avcodec/x86: add an 8-bit simple IDCT function based on the x86-64 high depth functions

[James Darnley]

On 2017-06-16 03:58, Michael Niedermayer wrote:
> On Thu, Jun 15, 2017 at 05:08:33PM +0200, James Darnley wrote:
>> Includes add/put functions
>>
>> Rounding contributed by Ronald S. Bultje
>> ---
>> I must be stupid.  I dropped the stack space change somewhere.
>>
>>  libavcodec/tests/x86/dct.c       |  2 +
>>  libavcodec/x86/idctdsp_init.c    | 23 ++++++++++
>>  libavcodec/x86/simple_idct.h     |  9 ++++
>>  libavcodec/x86/simple_idct10.asm | 94 ++++++++++++++++++++++++++++++++++++++++
>>  4 files changed, 128 insertions(+)
> 
> theres something wrong with this
> it totally breaks this:
> make -j12 ffmpeg && ./ffmpeg -ss 1 -i cache:matrixbench_mpeg2.mpg -t 2 -y test.avi
> ./ffplay test.avi
> 
> (totally as in bitstream errors not some idct artifacts)

How did you manage to break it that much?  I don't touch avformat.  I
don't touch the rest of the decoder.

I don't have that file to test with and the cut down version which I
think is in fate is only 0.96 seconds long.  However trying your command
on that file successfully decodes 1 frame from it.  I made decoding it
with the new functions the fate test I added.  All the other fate
samples in mpeg2/ decode seemingly fine with no extra messages.