[Libav-user] swscale YUV444P10 -> RGB48LE

[Paul B Mahol]

On 4/22/13, Al Crate <al at dneg.com> wrote:
> On 22/04/13 10:22, Paul B Mahol wrote:
>> On 4/22/13, Al Crate <al at dneg.com> wrote:
>>> Hi all,
>>>
>>> I've been trying to explode a ProRes 444 movie to a sequence of 16bit
>>> images. It would appear that this doesn't work as libswscale always
>>> outputs non full chroma when converting YUV->RGB.
>>>
>>> Can someone confirm my suspicion ?
>>
>> What "outputs non full chroma" means?
>>>
>>> cheers
>>>
>>> al
>>>
>>>
>>>
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>
> When you look at the output (converted to back YUV) you get 422 i.e.
> half the expected number of UV samples.
>
> I suspect this piece of code in libswscale (util.c) might be the cause.
>
> Line 1031:
>
>      /* reuse chroma for 2 pixels RGB/BGR unless user wants full
>       * chroma interpolation */
>      if (flags & SWS_FULL_CHR_H_INT &&
>          isAnyRGB(dstFormat)        &&
>          !isPlanarRGB(dstFormat)    &&
>          dstFormat != AV_PIX_FMT_RGBA  &&
>          dstFormat != AV_PIX_FMT_ARGB  &&
>          dstFormat != AV_PIX_FMT_BGRA  &&
>          dstFormat != AV_PIX_FMT_ABGR  &&
>          dstFormat != AV_PIX_FMT_RGB24 &&
>          dstFormat != AV_PIX_FMT_BGR24 &&
>          dstFormat != AV_PIX_FMT_BGR4_BYTE &&
>          dstFormat != AV_PIX_FMT_RGB4_BYTE &&
>          dstFormat != AV_PIX_FMT_BGR8 &&
>          dstFormat != AV_PIX_FMT_RGB8
>      ) {
>          av_log(c, AV_LOG_WARNING,
>                 "full chroma interpolation for destination format '%s'
> not yet implemented\n",
>                 av_get_pix_fmt_name(dstFormat));
>          flags   &= ~SWS_FULL_CHR_H_INT;
>          c->flags = flags;
>      }
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>

Hmm, indeed, then open bug report.