Windows 7 + VC-1

[RonaldoSan]

Windows 7 supports decoding of various formats out of the box. H.264 playback is there and it decodes fine through DirectShow. VC-1 playback is there, but when AviSynth tells it to decode through DirectShow it does not work.

I can use libavcodec for VC-1 decoding (with a little fiddling around), but playback shows artifacts when jumping and so does the compression tests I make.

http://i25.tinypic.com/21188so.jpg

I would guess it does not make for a good compression test then. Is there any way to get Microsoft's decoder to work through DirectShow or get rid of the libavcodec artifacts?

[Atak_Snajpera]

select wmv9 decoder in ffdshow

[RonaldoSan]

That worked, but playback and the compression test still shows the those artifacts.

It's not a problem when encoding a full film, but when doing the compression test every 4-5 skips there are some artificats. I guess it shouldn't be a big deal.

Thanks anyways :D

[vwpassion]

I had the same problem on Windows Server 2008 64-bit.

I couldn't get wmvideo dmo decoder to work at all. Then I tried ffdshow in combination with wmv9 decoder, but in Vdub there were artefacts that you described as well. I figured it's a decoding issue.

Are you sure the glitches aren't present in your encoding, despite them showing up in Vdub?

[RonaldoSan]

I can provoke the artefacts during playback with Windows Media Player when using ffdshow (wmv9 or libav). If I use the Microsoft decoder for playback it's perfect. So it must be an issue with ffdshow.

[vwpassion]

Have you managed to create a graph with wmvideo dmo decoder and load that into Vdub (through avisynth) ?

[RonaldoSan]

The graph worked perfect. Incredible!

Thanks for the help guys.

[benwaggoner]

Hmmm. My first guess is a decode bug with B-frames or potentially differential quantization. ffmpeg traditionally hasn't decoded either of those well.