[FFmpeg-devel] [PATCH] more libx264 parameters

[Loren Merritt]

On Thu, 18 Mar 2010, Michael Niedermayer wrote:
> On Wed, Mar 17, 2010 at 05:06:59PM -0700, Baptiste Coudurier wrote:
>>
>> -flags2 +psy (activated by default)
>
> but first, do we need a psy flag, is not setting some of the float parameters
> to 0 naturally disabling it? no i am not upto date with x264 encoding options

The psy flag also affects a number of minor psy optimizations that don't 
have their own strength variables.

>> +#define CODEC_FLAG2_SSIM          0x00100000 ///< Compute SSIM during encoding
>
> is the value made available through AVFrame.error[] or just printed
> to the terminal, printf would be a bit annoying, in light of av_log()
> expectance of applications.

Only printed, though libx264 supports an av_log callback to replace printf.

>> +    /**
>> +     * AQ strength
>> +     * Reduces blocking and blurring in flat and textured areas. [1.0]
>> +     */
>> +    float aq_strength;
>
> is this semantically different from our *cplx_mask fields?

It's a different algorithm, has a different range of valid inputs, and I 
recommend that people do use x264's aq but not use spatial_cplx_masking.
Other than that, no.

>> +    /**
>> +     * RC lookahead
>> +     * Number of frames for frametype lookahead
>
> ratecontrol or frametype lookahead or both?

Both.

--Loren Merritt