Video corruption when playing older h.264 media

[Prospero424]

There are several separate problems currently being had with video artifacting being experienced on the Boxee Box and in the Boxee software. This post is designed to help people spot when it is being caused by incompatibilities between older versions of h.264 encoders and current hardware acceleration methods. In particular, videos encoded with older versions of x264 (roughly two years old or more) will often display this sort of artifacting.

The artifacts being discussed here will manifest on any known platform using hardware-accelerated AVC (h.264) playback, but they will often appear more or less severe on different devices using different decoding engines.

Here is a recent example from the forums. This encode of The Matrix was done more than three years ago. This is a picture taken of the artifacts as they appear on the Boxee Box:



And here is how they appear on the exact same video file when playing through VLC (with GPU acceleration enabled) under Windows 7 with an Nvidia card:



The artifact remains regardless of the hardware decoder being used. The only circumstance under which it will not manifest is when the video is being decoded purely in software.

Remember that hardware acceleration of video files in consumer devices is still relatively new. Even a couple of years ago, it was bleeding edge.

Videos encoded with any version of x264 from roughly the past two years don't seem to exhibit this problem. So the key to avoiding this is to make sure your encoding software is up to date. Advancements and refinements to encoders like x264 are being made all of the time.

[judgeschambers]

As usual, Prospero424, nice post!

[jahamala]

Thanks for getting this knowledge out there for others, as I think this an example from one of my posts.

So I'm guessing a re-encode would be the only work around? Or is there a possible software fix?

It'll be a huge pain to identify all of the problem videos in my collection without some type of automated script or something. It may be possible to script something with MediaInfo to look at all of them, but I don't even know if it would give me any data to identify the bad encode without manually watching the movie.

[Prospero424]

If this is indeed the problem you're having, then yeah, a reencode is the only way to fix it.

You could just use a script to have Mediainfo identify any movie with an "Encoded date" of more than two and a half years (or so) ago or more and manually check all of them that come up, but I don't think there's any way to make it more automatic than that.

[Mavrick]

This raises an interesting question. Store your collection as larger ISO's or convert them?

I'm in the process of converting my ISO's to XviD format with AutoGK. My thought was saving disk space. I can take a 4-6GB ISO and compress it to 1.5-2GB avi file and still have great quality.

Now my concern is; am I shooting myself in the foot? Would it be safer to keep them in ISO format for future compatiblity reasons? I know it's easier to burn a disc with them in ISO format, but I'm trying to get away from all those plastic backup discs. In XviD format I can easily double my storage capacity.

What to do?

[Prospero424]

I guess it depends on what you're willing to invest as far as storage. What a lot of people do is keep the .iso files in "offline" storage either on plastic discs (which I know you said you don't like, and I agree) or on, say, an old hard drive they don't use anymore that they can keep in a filing cabinet or what have you.

Then they keep the compressed version in "online" storage: on hard drives currently in use that can be readily accessed by multiple devices. This is what I do.

AutoGK is nice, and XViD can produce very good quality, but you can get even more quality for the file size desired with AVC (h.264) these days, especially with HD content. You also get more reliable and more widely-compatible hardware acceleration capability. So I'd suggest compressing your .iso files to .mp4 (if you only need stereo audio) or .mkv using some sort of front end for the x264 encoder. My guide for encoding to this format is right below this thread in the announcements forum.

The only advantage AutoGK/XViD offers anymore is encoding speed. It will take less time to encode the same movie to XViD than it will to encode it to AVC. But that's the price you pay for quality.

Anyway, it's all up to you. You're the only one who can set your priorities. Plenty of options out there to play around with.

[dmanpohlman]

What's interesting is using the same hardware playing the same video on boxee on windows 7, I get artifacts, but if I play the same video using something like Splash lite from Mirillis it plays perfectly fine with hardware acceleration.

If the decoding is truly being done in the hardware, what is Splash doing differently than Boxee?

This is with ATI HD 3450 and Catalyst 10.12 drivers.

[Prospero424]

I just tested the Matrix corruption sample I used to make those screenshots above in the Splash Lite player you referenced, and the same corruption as in the second shot still clearly manifests.

It may very well be that Nvidia's h.264 decoding engine doesn't get rid of some of these artifacts while ATi's does.

[dmanpohlman]

Thanks for the quick response, I understand what you are saying, but for me it is on the same ati 3450 hardware. I see the corruption in Boxee and XBMC for that matter, but not in the Splash Lite player.

So, that's what leads me to ask, if you witness the same issue using Splash Lite using Nvidia, and I don't using Ati, is Splash Lite doing something different with just ATI drivers to fix the issue. I can't see why they wouldn't with Nvidia as well.

Very interesting indeed.

[Prospero424]

Well, as long as you're 100% sure that you do indeed have hardware decoding enabled in Splash Lite, I suspect that there's something different with the ATi hardware decoding engine when compared to the other hardware decoders out there that Mirillis has taken advantage of.

Alternatively, we could conceivably be talking about two different types of artifacts, although they are likely related in any case.

To eliminate that, I'd like you to try this same sample (download here), making doubly sure that GPU acceleration is enabled in the Splash player, and let me know if you see the corruption in the second screenshot above.