[FFmpeg-user] trouble confirming ffv1 lossless encode

[Nathan Lewis]

On Fri, Feb 1, 2013 at 6:20 AM, Peter B. <pb at das-werkstatt.com> wrote:

> @Nathan:
> Have you tried Carl Eugen's suggestion?
>
> If there are still issues with verifying FFv1's losslessness is your
> case, could you upload your uncompressed sample somewhere, so I could
> take a look at it?


Hi Peter,
I was able to test using Carl Eugen's suggestion and I was able to verify
ffv1's losslessness using -pix_fmt yuyv422 when running framemd5 on the
ffv1.

@Carl Eugen:
Apologies for the delay in getting back to you with an update.  I
appreciate your quick response to my question.

I have a few follow up questions about the use of -pix_fmt in this example.
 Please let me know if this warrants a new posting/thread.

My input file (8-bit Uncompressed from a Digital Rapids DRC-1400) is
yuyv422.  Looking over the -pix_fmts available to ffv1 in ffv1enc.c I found
that yuyv422 is not supported within ffv1:

1143<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1143>
   .pix_fmts       = (const enum AVPixelFormat[]) {
1144<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1144>
       AV_PIX_FMT_YUV420P,   AV_PIX_FMT_YUVA420P,
AV_PIX_FMT_YUVA422P,  AV_PIX_FMT_YUV444P,
1145<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1145>
       AV_PIX_FMT_YUVA444P,  AV_PIX_FMT_YUV440P,   AV_PIX_FMT_YUV422P,
  AV_PIX_FMT_YUV411P,
1146<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1146>
       AV_PIX_FMT_YUV410P,   AV_PIX_FMT_0RGB32,    AV_PIX_FMT_RGB32,
  AV_PIX_FMT_YUV420P16,
1147<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1147>
       AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
AV_PIX_FMT_YUV444P9,  AV_PIX_FMT_YUV422P9,
1148<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1148>
       AV_PIX_FMT_YUV420P9,  AV_PIX_FMT_YUV420P10,
AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
1149<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1149>
       AV_PIX_FMT_GRAY16,    AV_PIX_FMT_GRAY8,     AV_PIX_FMT_GBRP9,
  AV_PIX_FMT_GBRP10,
1150<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1150>
       AV_PIX_FMT_GBRP12,    AV_PIX_FMT_GBRP14,
1151<http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ffv1enc.c#l1151>
       AV_PIX_FMT_NONE


Would it be better to force the -pix_fmt to something other than the
default yuv422p for encoding into ffv1?

I assume that yuv422p represented 8-Bit Planar YUV and yuv422p10
represented 10-bit Planar YUV.  Is there some place within the ffmpeg
source (or elsewhere) where I might find some more detail about the
colorspaces/pix_fmts available to different codecs within ffmpeg?

Regards,

Nathan