#94 Output colorspace as-is

closed
nobody
None
5
2014-09-22
2011-12-12
CoRoNe
No

original post on Doom9's forum: http://forum.doom9.org/showthread.php?p=1329345#post1329345 and http://forum.doom9.org/showthread.php?t=156427

By default FFDShow's Video Decoder output is in all cases YV12 video, but in my opinion the "Primary output color space" feature on the Output-tab of the Video Decoder config should actually be "Override output color space", and FFDShow's Video Decoder output should be whatever the file specifies.
Right now Fraps-files (always RGB32), HFYU(RGB32) and FFV1(RGB32) for instance, but practically everything non-YV12, FFDShow converts to YV12. It's the same when an audio decoder by default would automatically convert the audio stream to 22050Hz for instance, no matter the input. I really don't understand this behaviour.
I'd like to see FFDShow respecting the input colorspace by default, no more automatic colorspace conversions, and having the "Primary output color space" feature being renamed to "Override output color space", or at least introduce a boolean feature something like "Output colorspace as-is".

Discussion

  • h.yamagata

    h.yamagata - 2011-12-22

    >>By default FFDShow's Video Decoder output is in all cases YV12 video,
    This is not correct. ffdshow outputs 10-bit YCbCr for such input. ffdshow outputs YUY2 for 4:2:2 8-bit. AYUV for 4:4:4 8-bit, if checked.
    But if some image filters are used, color space conversion may be forced as most image filters do not accept other than YV12. Resize accepts most color spaces and output the same color space. Subtitles prefer RGB32 output. For such cases, ffdshow may output YV12 or something to avoid further color space conversion.
    As you pointed, for some RGB codecs, YV12 output is used. This should be fixed in the future.
    Sorry, I have no plan to change the audio decoder's behavior.
    "Override output color space" may be a good idea. clsid, what do you think?

     
  • CoRoNe

    CoRoNe - 2011-12-22

    >>As you pointed, for some RGB codecs, YV12 output is used. This should be
    fixed in the future.
    That would be great.

    >>Sorry, I have no plan to change the audio decoder's behavior.
    Sorry, am I missing something? I haven't mentioned FFDShow's Audio Decoder here.

    P.s. In my mailbox I saw "kirakami" has commented twice. Where have his comments gone?
    >>basically you mean instead of forcing YV12 for all
    ffdshow should automatically use colorspace specified by video file, right?
    Exactly. Unless an override output color space is specified.

     
  • Marijo

    Marijo - 2011-12-22

    @corone17:
    I've hidden kirakami's useless posts. As usual, they're off-topic and completely pointless.

     
  • h.yamagata

    h.yamagata - 2012-01-30

    >Right now Fraps-files (always RGB32), HFYU(RGB32) and FFV1(RGB32) for instance,
    >but practically everything non-YV12, FFDShow converts to YV12.

    After more search, they are not always RGB32. More commonly they are YV12. I think your video clips are all YV12. I think ffdshow outputs RGB32 if they are encoded RGB32 (not tested enough though). If you encoded the clip yourself and you are sure they are RGB, please send them.

    I think "Override output color space" is not better than current one. "Primary output color space" is tested first and if it is rejected, other supported color spaces are used. "Override" sounds like no other spaces are allowed.

    I think I have nothing to change.

     
  • CoRoNe

    CoRoNe - 2012-01-30

    Yes I made these videoclips myself, but nevermind. I rest my case. I've totally had it with this stuff. Seems I can't trust FFV1 or even H.264 for rgb-content at all. Selecting RGB32 FFV1 in the VFW config doesn't produce RGB32 FFV1 at all...so back to good old HFYU (or Lagarith and alike) for RGB32.

     
  • clsid

    clsid - 2012-02-07
    • status: open --> closed
     

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