[FFmpeg-devel] [PATCH] Make vp3dsp*.c compilation optional

[Aurelien Jacobs]

On Mon, 14 May 2007 14:27:04 +0200
Panagiotis Issaris <takis.issaris at uhasselt.be> wrote:

> Hi,
> 
> The attached patch tries to make the vp3dsp*.c compilation optional.
> Again, not meant for direct inclusion, as I am not sure about the
> correctness... I am a bit confused about Theora decoding:
> 
> In dsputil_init() it seems ff_vp3_idct_* functions are being used to
> decode Theora:
>     3886         }else if(avctx->idct_algo==FF_IDCT_VP3){
>     3887             c->idct_put= ff_vp3_idct_put_c;
>     3888             c->idct_add= ff_vp3_idct_add_c;
>     3889             c->idct    = ff_vp3_idct_c;
>     3890             c->idct_permutation_type= FF_NO_IDCT_PERM;
> 
> 
> While in dsputil_init_mmx() it seems they are explicitly avoided for
> decoding Theora:
>     3282             }else if(idct_algo==FF_IDCT_VP3 &&
>     3283                      avctx->codec->id!=CODEC_ID_THEORA &&
>     3284                      !(avctx->flags & CODEC_FLAG_BITEXACT)){
>     3285                 if(mm_flags & MM_SSE2){
>     3286                     c->idct_put= ff_vp3_idct_put_sse2;
>     3287                     c->idct_add= ff_vp3_idct_add_sse2;
>     3288                     c->idct    = ff_vp3_idct_sse2;
>     3289                     c->idct_permutation_type=
> FF_TRANSPOSE_IDCT_PERM;
>     3290                 }else{
> 
> Is something fishy or am I just misinterpreting the code?

The MMX and SSE2 versions of vp3dsp produce artifacts when decoding
theora (but they are ok when decoding vp*). They need to be fixed,
but in the mean time, they are simply disabled for theora.
So for now, you can consider this is the expected behavior.

> The attached patch assumes the current code mentioned above is correct.

Patch mostly ok. See my remark.

>  OBJS-$(CONFIG_GPL)                     += i386/idct_mmx.o
>  OBJS-$(CONFIG_CAVS_DECODER)            += i386/cavsdsp_mmx.o
>  OBJS-$(CONFIG_SNOW_DECODER)            += i386/snowdsp_mmx.o
> +OBJS-$(CONFIG_VP3_DECODER)             += i386/vp3dsp_mmx.o i386/vp3dsp_sse2.o
> +OBJS-$(CONFIG_VP5_DECODER)             += i386/vp3dsp_mmx.o i386/vp3dsp_sse2.o
> +OBJS-$(CONFIG_VP6_DECODER)             += i386/vp3dsp_mmx.o i386/vp3dsp_sse2.o
> +OBJS-$(CONFIG_THEORA_DECODER)          += i386/vp3dsp_mmx.o i386/vp3dsp_sse2.o
>  endif

The MMX and SSE2 versions don't need to be built for theora...
Except that, patch is ok.

Aurel