Re: Fix de/selection of libx264 I-partitions

Panagiotis Issaris schreef:
> Hi,
> 
> Loren Merritt wrote:
>> On Thu, 26 Jul 2007, Panagiotis Issaris wrote:
>>
>>   
>>> I've noticed that when using ffmpeg, using
-partitions -parti4x4 doesn't
>>> work as I had expected. Although I was trying
to disable the generations
>>> of 4x4 blocks, the output of ffmpeg would still
contain:
>>> ...
>>> mb I  I16..4: 59.1%  0.0% 40.9%
>>> ...
>>>
>>> The attached patch fixes the selection and
deselection of the usage of
>>> certain blocksizes when using libx264.
>>>     
>> ffmpeg is currently consistent with mencoder and
x264cli: the "partitions" 
>> option affects only P- and B-frames, while I-frames
always use all 
>> available partitions. Because the only reason for
disabling partitions is 
>> speed, and intra partitions in I-frames gain much
more compression per 
>> cpu-time than in P- and B-frames.
>>
>> If you want some way to disable partitions in
I-frames, that's another 
>> question. But don't change the meaning of an
existing option.
>>
>>   
> Ah, I see. Well, from a user point of view, it seemed
logical to me that
> disabling I4x4 blocks would do so in both I and P
frames, but I also
> think my patch was wrong in that sense too. It should
have also kept
> OR-ing analyse.inter with the I4x4's and I8x8's as I
now always entirely
> disabled them for P frames, right?
> 
> I'll try to prepare a different patch, introducing a
way to disable them
> for I frames, without changing existing options.

Attached a patch introducing new parameters for -partitions,
being
"parti4x4i" and "parti8x8i". The patch
does alter the current behavior
as with this patch 4x4 and 8x8 partitions for I frames
aren't used
anymore by default. Any thoughts on that?

 avcodec.h |    2 ++
 libx264.c |    8 ++++++++
 utils.c   |    2 ++
 3 files changed, 12 insertions(+)


With friendly regards,
Takis
--
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PGP key: http://issaris.org/pi.key

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Panagiotis Issaris schreef:
> Panagiotis Issaris schreef:
>> Hi,
>>
>> Loren Merritt wrote:
>>> On Thu, 26 Jul 2007, Panagiotis Issaris wrote:
>>>
>>>   
>>>> I've noticed that when using ffmpeg, using
-partitions -parti4x4 doesn't
>>>> work as I had expected. Although I was
trying to disable the generations
>>>> of 4x4 blocks, the output of ffmpeg would
still contain:
>>>> ...
>>>> mb I  I16..4: 59.1%  0.0% 40.9%
>>>> ...
>>>>
>>>> The attached patch fixes the selection and
deselection of the usage of
>>>> certain blocksizes when using libx264.
>>>>     
>>> ffmpeg is currently consistent with mencoder
and x264cli: the "partitions" 
>>> option affects only P- and B-frames, while
I-frames always use all 
>>> available partitions. Because the only reason
for disabling partitions is 
>>> speed, and intra partitions in I-frames gain
much more compression per 
>>> cpu-time than in P- and B-frames.
>>>
>>> If you want some way to disable partitions in
I-frames, that's another 
>>> question. But don't change the meaning of an
existing option.
>>>
>>>   
>> Ah, I see. Well, from a user point of view, it
seemed logical to me that
>> disabling I4x4 blocks would do so in both I and P
frames, but I also
>> think my patch was wrong in that sense too. It
should have also kept
>> OR-ing analyse.inter with the I4x4's and I8x8's as
I now always entirely
>> disabled them for P frames, right?
>>
>> I'll try to prepare a different patch, introducing
a way to disable them
>> for I frames, without changing existing options.
> 
> Attached a patch introducing new parameters for
-partitions, being
> "parti4x4i" and "parti8x8i". The
patch does alter the current behavior
> as with this patch 4x4 and 8x8 partitions for I frames
aren't used
> anymore by default. Any thoughts on that?
> 
>  avcodec.h |    2 ++
>  libx264.c |    8 ++++++++
>  utils.c   |    2 ++

Reindent after this patch.

 avcodec.h |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

With friendly regards,
Takis
--
vCard: http://issaris.org/pi.vcf
PGP key: http://issaris.org/pi.key

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