DGIndex vs DirectShowSource

[JoeH]

I was wondering what advantages using an AVS with DGIndex offers over AVS with DirectShowSource. After all, I can open up any H264 or VC1 stream using DirectShowSource, adding the fps and convertfps.

In my case I use DirectShowSource / DGIndex only for video - I handle audio completely apart.

[avivahl]

Depending on the DirectShow decoder used, you might not get frame accuracy w/ DirectShowSource().
Also, those using DG NV tools get CUDA video decoding (which frees the CPU to do other things, like audio processing).
Some people also reported (http://forum.doom9.org/showpost.php?p=1359393&postcount=820) that CUDA handles some videos that other filters didn't.

Or were you talking only about the non-CUDA DG tools?

[Varies]

So, DirectShowSource is slooooow and video loaded over DSS might be changed by decoder. also, i think DGAVCIndex not good alternative for AVC streams because use old libavcodec.
Usually i use dss2 & coreavc decoder with CUDA acceleration, it's got good result for me, for MPEG2 streams DGIndexNV best choice :)
I scare use embedded deinterlace, once i saw very bad changes in loaded source and i decide not use it before upgrade my gt 250 to something with VP4+ ^ ^)

[JoeH]

Thanks for the replies. So, frame accuracy and CUDA decoding are the advantages, plus at times better decoding quality?

For me, the first two of those would be particularly important, especially the frame accuracy if I make cuts in a video.

[avivahl]

Quality depends on the type of source you are decoding. If it's H.264, it should be bit-exact to any other proper decoder out there. If it's MPEG-2, quality varies depending on which decoder is used.
And, of course, deinterlacing and postprocessing (on sources that need it) affect the final output as well.

[Asmodian]

H.264 is supposed to be the same for all decoders but weight p and other features have had caused artifacts with some decoders; nvidia's CUDA has been the most robust for avisynth (as far as I know of course :p).

[avivahl]

H.264 is supposed to be the same for all decoders but weight p and other features have had caused artifacts with some decodersThat's why i wrote "proper". :P (=bug-less)

[JoeH]

On a lot of MPEG2/H264/VC1 files I need to add a ColorMatrix() command to the AVS script to get the colors to look just right when I use DirectShowSource.

Does DGIndexing a file make this no longer necessary? I noticed that one of the things it includes in the log is the REC colorspace.

[Asmodian]

That's why i wrote "proper". :P (=bug-less)

Are there are any "proper" H.264 decoders (that support all in spec features completely)?

[kypec]

I'd say JM reference decoder is the tool to check out.