Slashdot Mirror
VP8 and H.264 Codecs Compared In Detail
An anonymous reader writes "Moscow State University's Graphics and Media lab have released their sixth MPEG-4 AVC/H.264 video codecs comparison. Also of note is a recently added appendix to the report which compares VP8, x264, and Xvid. The reference VP8 encoder holds its own against x264 despite the source material offering x264 a slight advantage. The VP8 developers comment in the report: 'We've been following the MSU tests since they began and respect the group's work. One issue we noticed in the test is that most input sequences were previously compressed using other codecs. These sequences have an inherent bias against VP8 in recompression tests. As pointed out by other developers, H.264 and MPEG-like encoders have slight advantages in reproducing some of their own typical artifacts, which helps their objective measurement numbers but not necessarily visual quality. This is reflected by relatively better results for VP8 on the only uncompressed input sequence, "mobile calendar."'"
Input content *will* usually have been compressed with H264. Even the likes of Google will find itself transcoding 99% of its content into VP8 from some other codec. That might suck for comparison tests but its a fact of life.
One is an extorsion accessory, the other is not (yet).
Unfortunately their statement is very misleading considering how VP8 and H.264 and other MPEG codecs use basically the same transform so their statements of bias against VP8 ring untrue. One of the professors who was part of doing this test even confirmed that the VP8 developers statement was untrue and misleading.
"The reference VP8 encoder holds its own against x264 despite the source material offering x264 a slight advantage."
Um, sure, if VP8 on its "best" preset being roughly equivalent to x264 on its "high speed" preset means it's holding its own, I guess that's a fair statement.
It will all come down to support. Which codec has the widest support.
Even Firefox will eventually add H.264 support even if it is with a plug in.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
I don't understand the "VP8 holds its own against x264".... The graphs show that it certainly does not hold it's own against x264. For example, if you look at the best quality settings of x264 vs VP8 for the Ice Age clip, at the same quality (SSIM=0.97), x264 takes 800Kbps while VP8 takes ~1.2Mbps... So VP8 takes 50% more bits to achieve the same quality. This shows that VP8 is not nearly as efficient as x264. (Also, note that x264 is only one implementation of an H.264 encoder. There are other implementations that will make different tradeoffs to get better compression efficiency at the cost of performance).
Since when did "near enough" become "good enough"? We might as all switch to Windows...
You can do realtime, baseline H.264 encoding on Cortex A8 and A9 chips with x264.
While looking at encoder comparisons, keep in mind this post from a x264 developer about cheating on encoder comparisons. I'm not saying that these guys are cheating, just things to look out for.
iPhone 4 records video at 10.8 Mbps baseline 3.1, 1280x720 at 29.97fps. Most of the DSLRs that shoot video, shoot in h264 and consumer cameras are increasingly switching to h264 as they dump tape based recording methods. It's nice that the authors didn't really bother trying to find properly high bitrate stuff as source materials. Oh well.
H.264 doesn't actually use a DCT, but a non-exact integer approximation to a DCT, the Integer Cosine Transform, which is exactly invertible,, at the cost of a slightly loss of accuracy in the transform coefficients . (Floating point DCTs have rounding errors, and thus are not exactly invertible. If content is encoded multiple times, then the numerical noise introduced by this will accumulate to troublesome levels.)
Most video material comes, originally, from a camera of some sort. (Obviously, this isn't the case for animation.) All of the HD camera systems I know of record in H.264, MPEG-4 or MPEG-2. (It might be called HD-DV or something else, but it's MPEG compressing under the hood.) So, if that gives H.264 an advantage, there isn't much that can be done about it. It will take a long time to replace all of the camera gear out there...
It's also almost never H264 first but MJPEG/XVid/MPEG2/etc and NOT H264. For a start, encoders for mobile phones don't have the power to encode H264 live. So the OP assertion is obviously and trivially wrong.
Really? My team works with a lot of Prosumer cameras that output H264. There's a quickly growing amount of content on YouTube and elsewhere that's filmed on such cameras, or even their lower end brethren - which also often output in H264.
StarTrekPhase2 - The Five Year Mission Continues!
And there's almost two billion chinese trying to make hardware that doesn't infringe pattens so they can sell obscenely cheaper here in the west.
The manufacturer's license for H.264 is $0 - for sales of 100,000 units or less each year.
20 cents a unit - for sales of 100,001 to 5 million units a year.
10 cents a unit - for sales above 5 million a year.
With an "Enterprise Cap" of $5 million a year.
SUMMARY OF AVC/H.264 LICENSE TERMS
The Korean Samsung Group - for comparison - has about a quarter of a million employees and annual revenues of $170 billion.
I was under the impression that there is no standard for encoding a video stream, and that the standard is in the decoding of the stream.
It makes it unlikely that this comparison of codecs shows the full potential of one standard over another - and I would be wary of drawing any conclusions.
What's more VP8 also uses an integer approximation to the DCT, but a different one to H.264 (quite possibly the H.264 version is patented).
...Which brings us back to the "for now" part of the comment.
If you're a camcorder manufacturer, chances are you're using H.264 (and paying licensing fees to do so) precisely because it's convenient for people to upload to YouTube and otherwise muck with the video without having to transcode it. If that changes because YouTube and other mainstream sites and software support VP8, and you have the ability to offer consumers the option of doing the same thing without paying licensing fees by encoding in VP8, you'll likely do so to increase your profit margin.
Your logic here supports the chicken-and-egg scenario that MPEG is praying for: manufacturers unwilling to support a format not in common use, and a format won't get in common use because manufacturers won't support it. As Google and other companies break the cycle by convincing people that the format will come into common support, manufacturers will be more willing to jump on board, bringing consumers with them.
While most of the card ones are AVCHD which is H.264, HDV cameras are MPEG-2. They are quite popular as there's reason to want tape as a storage medium.
Then of course in terms of pro video, it is still compressed, raw video is just too daunting to store, but again with different codecs. They are often takeoffs of DV where there is just very light per frame compression as well as chroma downsampling. That offers better quality on subsequent recompression and editing, as well as lower hardware requirements to encode.
This idea that everything will be H.264 as a source is inaccurate. It is popular no doubt, and I believe it will continue to be, but it isn't universal and probalby won't be.