Decoding filters in Windows 7 - Microsoft vs FFDShow

[thedozer]

I just installed windows 7 and I learned that it uses its own DirectShow filters for decoding video.

I have some HQ videos in x264 and XVID formats and I wish to re-encode them into smaller x264.

My question is:
What will be better to decode x264 and XVID videos for the encoding process in terms of quality...
Microsoft Filters or FFDshow?

Thanks in advance

[LoRd_MuldeR]

Any H.264 decoder will deliver exactly the same decompressed output for the same input stream. Well, given that the decoder isn't broken ;)

If at all, ffdshow may be superior because of its additional post-processing filters (resize, sharpen, colorspace conversion, etc), which are NOT part of the H.264 decoding process.

You should also have a look at the DivX H.264 Decoder filter, which is available for free and faster than both, Microsoft's decoder and ffdshow's (libavcodec's) decoder.

(BTW: Such thing as a "x264 format" does NOT exist! The video format is called "H.264" aka "MPEG-4 AVC". One encoder software that creates H.264/AVC video is called "x264")

[sneaker_ger]

While we're talking about broken H.264 decoders: Wasn't DivX one 'em? (Faulty deblocking or something IIRC)

[thedozer]

I've been using FFDShow for a long time now it it has produced results that I find satisfying and wanted to know if there is anything special in other decoders,

and giving the fact that FFDShow is slightly faster and its frequently updated, I think it will be a better choice at the moment.

Thanks a lot LoRd_MuldeR for your help.

[LoRd_MuldeR]

While we're talking about broken H.264 decoders: Wasn't DivX one 'em? (Faulty deblocking or something IIRC)

I'm not aware of any noteworthy problems with DivX' H.264 decoder. It works fine for me with all streams I have tested. There may be (exotic) streams that make DivX' decoder failt though.

There was a prominent problem with CoreAVC and streams encoded by x264 with Weighted P-Frames. But it has been fixed in CoreAVC 2.0 and it never was a problem with DivX' decoder.

[sneaker_ger]

Found the posts I was referring to - but it wasn't only DivX:
http://forum.doom9.org/showpost.php?p=1354769&postcount=5387
http://forum.doom9.org/showpost.php?p=1354543&postcount=5344

[LoRd_MuldeR]

Found the posts I was referring to - but it wasn't only DivX:
http://forum.doom9.org/showpost.php?p=1354769&postcount=5387
http://forum.doom9.org/showpost.php?p=1354543&postcount=5344

Well, that post only says that any of the "major" H.264 decoder has some remaining issues. Including DivX and libavcodec (ffdshow).

But it doesn't mean that you actually will run into problems with your stream. And even if you do, you probably won't notice, because the problem isn't visible ^^

[sneaker_ger]

That maybe true, but we're all here on Doom9 because we're perfectionists, aren't we?
I haven't tested it myself so I can't say if these problems are visible. Given that I never saw anyone complain about artifacts and DivX isn't in DS's Hall of Shame it's probably not easily noticeable. (If at all to the naked eye)

[LoRd_MuldeR]

That maybe true, but we're all here on Doom9 because we're perfectionists, aren't we?

Sure. But if any of the "major" H.264 decoders has some issue with specific streams, what do you want to use then? :o

According to the post you cited, the only decoder that (so far) produces 100% "correct" result for any (valid) stream is the JM Reference decoder.

And that one probably is way too slow to be useful...

[sneaker_ger]

As long as there's no quick way of determining if a file will be decoded correctly by a given decoder, you're right. When I made my original statement I could only recall DivX being faulty.

[schweinsz]

libavcodec: There is at least one weird conformance vector it fails on, relating to MMCO + long term refs.
DivX: incorrect deblocking with duplicate refs
Mainconcept: incorrect motion compensation with duplicate refs
Elecard: broken direct mode with duplicate refs, incorrect handling of delta quants > 25
While the DiAVC hasn't these problems.

[xer0z]

While the DiAVC hasn't these problems.

I was just about to try the DiAVC codec but i get the message "The DiAVC Trial version is expired!", can you release a new trial version?

[porfitron]

I have some HQ videos in x264 and XVID formats and I wish to re-encode them into smaller x264.Aside from offering our H.264 decoder for free in the DivX 7 bundle, we also have our DivX Plus Tech Preview of MKV on Windows 7, if you're planning using MKV for your new encodes. The nice thing about this Tech Preview it allows for DXVA H.264 decoding in Windows Media Player and Windows Media Center because we enabled the MKV support via MediaFoundation (the Microsoft Decoders are used). Again, all these components are free, so try them out and judge for yourself... the installer allows you to install only the components you want if you're not interested in the DivX Player, etc.

Hit me up if you have more questions and we're always looking for feedback at DivX Labs.

[Keiyakusha]

Hit me up if you have more questions and we're always looking for feedback at DivX Labs.

Then sorry for hitting you in this topic, but Tech Preview 1.0 has a relatively big problem. It crashes the explorer if folder contains mkv file with just audio. Yes, named mkv, not mka, but still its bad when it crashes and you will need to rename file through commandline to be able to navigate to that folder again.