[FFmpeg-devel] Disable deblocking filter in H.264

Loïc lll+ffmpeg at m4x.org
Fri Jan 27 17:31:40 CET 2012

Hi Michael,

2012/1/26 Michael Niedermayer <michaelni at gmx.at>:
> On Thu, Jan 26, 2012 at 03:32:05PM +0100, Loïc wrote:
>> Hi,
>> To enable slice level threading on decoding, I'm trying to create
>> H.264 video streams without deblocking or with deblock type 2.
>> As I can't find a way to force deblocking type 2 in H.264 encoding
>> using libx264, I'm trying to use the second solution using "-flags
>> -loop" to disable deblocking filter, as explained in this page
>> http://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping, but it
>> seems that it isn't working.
>> The following commands are producing similar results:
>> ffmpeg -i in.mp4 -vcodec libx264 -b:v 10000000 -y -slices 4 -flags -loop out.mp4
>> ffmpeg -i in.mp4 -vcodec libx264 -b:v 10000000 -y -slices 4 out.mp4
>> In both cases, decoding the file with the following command:
>> ffmpeg -benchmark -thread_type slice -i out.mp4 -f null /dev/null
>> is outputing the same error message: "[h264 @ 0x15b3d00] Cannot
>> parallelize deblocking type 1, decoding such frames in sequential
>> order"
>> So it seems that the -flag -loop option isn't working.
>> Could you confirm this? Is there an other way to disable the
>> deblocking filter or to force type 2 in H.264 ?
> did you try -x264opts no-deblock ?

Thanks, it's working, deblocking is disabled and slice parallelism on
decoding is working.
I can also use "x264opts sliced-threads" to obtain deblocking filter
type 2 which is better than no deblocking and yet preserve thread_type

Best regards

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