[Ffmpeg-devel] [PATCH] TIFF encoder (Google SoC qualification task)

Michael Niedermayer michaelni
Thu Apr 5 21:03:59 CEST 2007


On Thu, Apr 05, 2007 at 06:37:16PM +0200, Kamil Nowosad wrote:
> Hi
> I'd like to add YUV support to tiff encoder. The specification says,
> that planar pixel formats are extension only. For example in libtiff
> they are unsupported. For this reason my solution is to add some
> tiff-compatible packed formats [none of existing is compatible]. I have
> now added only one format [YYUV422], but I'll add some more (this seems
> to be fully analogous).
> I've attached the patch, because I'm not completely sure if I don't do
> anything wrong and reviewing this on the early stage can avoid a lot
> of work later.
> -- 
> Best regards,
> Kamil Nowosad

> Index: libavutil/avutil.h
> ===================================================================
> --- libavutil/avutil.h	(wersja 8629)
> +++ libavutil/avutil.h	(kopia robocza)
> @@ -70,6 +70,7 @@
>      PIX_FMT_NONE= -1,
>      PIX_FMT_YUV420P,   ///< Planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
>      PIX_FMT_YUYV422,   ///< Packed YUV 4:2:2, 16bpp, Y0 Cb Y1 Cr
> +    PIX_FMT_YYUV422,   ///< Packed YUV 4:2:2, 16bpp, Y0 Y1 Cb Cr
>      PIX_FMT_RGB24,     ///< Packed RGB 8:8:8, 24bpp, RGBRGB...

breaks the ABI

[imgconvert related changes]

i didnt check the details but it looked conceptually correct, one thing
missing though is libswscale changes (yes adding new pix_fmts is not fun)

but i have doubts that adding yuv support like that is a good idea after
all, tiff doesnt define one packed yuv format they rather define how to
pack yuv with arbitrary subsampling, and none of the formats are standard
its all tiff invented, so adding all that as new pixel formats seems like
a lot of complexity for very little gain

so iam fine and would prefer if we would return to the original suggestion
from you guys that planar is converted to whatever weird packed format tiff
sorry for the bad pix_fmt suggestion i thought tiff would be using one of
the standard packed yuv variants

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No human being will ever know the Truth, for even if they happen to say it
by chance, they would not even known they had done so. -- Xenophanes
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