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| Unofficial VirtualDub Support Forums > Codec Discussion > Proper Output Color Depth For Huffyuv |
| Posted by: MrSmite Jun 29 2011, 07:19 AM |
| Trying to convert a .FLV using ffdshow VFW, the FLV input driver and HuffYUV 2.1.1 FFDshow decompresses the video as YUV420 but leaving the output format on "same as decompressor format" causes VDub to error saying it can't initialize the HuffYUV codec. I tried all the various options in the HuffYUV codec but nothing worked. The only way I could get it to process was to force the output format to a specific color space. My question is, out of the myriad of choices available, which one is closest to YUV420? I really don't know much about color spaces. For example, I forced it to '32 Bit RGB 888 (dummy alpha channel)' and it looked the same to me as when I used '4:2:2 YCbCr (YUY2)' Should I be using specific settings in FFDshow under 'output' and 'rgb conversion' or should I be forcing the conversion under VDub's 'color depth' Thanks |
| Posted by: MrSmite Jun 29 2011, 07:33 AM |
| Just remembered that VDub's filters all work in 32-Bit RGB so perhaps it would be best to simply leave that as the output? Again, I don't know much about color spaces but it would seem to me that if the source is decoded as YUV420, converted to RGB for filtering and then out as YUY2, there is more room for error than simply outputting it as RGB since the filters already converted it. |
| Posted by: phaeron Jul 2 2011, 10:46 PM | ||
This restriction was lifted a while ago and filters can optionally work in YCbCr space. Some of the internal filters have been updated to do so. The "show image formats" checkbox in the filter chain dialog will show which filters are causing conversions. Huffyuv is geared toward working with a few specific formats. The ones that it supports are 24-bit RGB, 32-bit RGB, and 4:2:2 YCbCr. In the last case, there are two compatible formats, UYVY and YUY2, and 4:2:2 planar can also be losslessly converted to and from those formats. There are some unofficially updated versions of Huffyuv that also support YV12 (4:2:0). If you are using the stock version of Huffyuv, 2.1.1, it does not support a format that can encode 4:2:0 YCbCr directly. |
| Posted by: MrSmite Jul 12 2011, 09:08 AM |
| Thanks for the reply, phaeron. I believe I'm using the stock HuffYUV plugin so that would explain the error message. I had been forcing 24-bit RGB and can't see any visual difference between that and 32-bit w/alpha. |