[x264-devel] Issues with intra refresh?

[Robert Logue]

On 14/01/12 18:29, BugMaster wrote:
> On Thu, 12 Jan 2012 16:51:01 +0000, Robert Logue wrote:
>> I forgot to add I am using libx264.so.120
>> On 12/01/12 16:37, Robert Logue wrote:
>>> Hello,
>>>
>>> When I was running a test harness to go to youtube and download random
>>> videos and transcode I found an issue. The issue is with intra-refresh
>>> turned on libx264 gives back different video for the same input video
>>> and params. This only seems to occur when the 1 process does multiple
>>> transcodes of the same file.
>>>
>>> To test this I altered the x264.c file to transcode the same input file
>>> twice and as output I got two different video files different file size
>>> and different frame data.
>>>
>>> The command I used was
>>>
>>> /spare/x264/install/bin/x264 --preset=veryfast --bitrate=300
>>> --tune=zerolatency --profile=baseline --intra-refresh --vbv-maxrate=300
>>> --vbv-bufsize=12000 --ipratio=0.4 --qpmin=10  -o ./output.mp4 ./input.mp4
>>>
>>> and the video can be found here
>>>
>>> http://199.91.152.89/nhnunbt586kg/5xzsdnshfcgj459/tram.mp4
>>>
>>> Note the video was downloaded by a random test harness and is quiet
>>> offensive. If possible it should not be watched and if watched the sound
>>> should be turned down.
>>>
>>> I was on the web chat earlier and the guys on there indicated that this
>>> could be a bug. Is there any where else to raise this or is here ok?
>>>
>>> Thanks
>>>
>>> Robert
> I can't reproduce your issue with one thread (add --threads 1 to your
> command line) about which you were talking on IRC. As for
> multithreading case the non-determinism is due use of VBV. So may be
> you attach you changes to x264.c because it most probably you messed
> up somewhere there or you used multithreading (even though you said
> you didn't but I don't see --threads 1 in your commandline).
>
> _______________________________________________
> x264-devel mailing list
> x264-devel at videolan.org
> http://mailman.videolan.org/listinfo/x264-devel
I have attached the file that I use, it could be that I have messed up 
some where ie not cleaned something up as I don't know the code well but 
I get similar results when I run x264 via gstreamer.

The modification I made to the file was in the main method. After the 
first transcode is done I start another transcode with the same input 
file and dump the second result in '/tmp/secondfile.mp4', the first 
output file is set as normal.

Thanks

Robert
-------------- next part --------------
A non-text attachment was scrubbed...
Name: x264.c.zip
Type: application/zip
Size: 20104 bytes
Desc: not available
URL: <http://mailman.videolan.org/pipermail/x264-devel/attachments/20120116/17ec9813/attachment-0001.zip>