H.264 Codec, Wow

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This codec is amazing!

Apple will soon be releasing a groundbreaking/all definition codec for quicktime called H.264.

I had the opportunity of seeing H.264 in action and talked to one of the head engineers of it, a young Check woman who's name I never took note of. The Codec will take a lot of proccessing to encode but it decodes so fast and preserves color amazingly! It's a 4:2:1 Mpeg-4 High quality codec with an inherant chroma shift of +2 that counters the compression effects. I've seen the previews of the movie Troy encoded in 1080p 24 FPS playing off the standard hard drive that comes with the machine. It played flawlessly and with no artifacts. 1 layer of 1080p on Apple's Seagate 160gb SATA hard drive is amazing. I've also seen it decoding 3 streams simultaneously, 1 720p, 1 ntsc, and one half size clip on the same setup.

This codec will be the one to watch when it comes out. The engineer doesn't know yet what Apple's reccomended equipment requirements will be to encode content with this codec but apparently it is very slow to encode and takes advantage of dual proccesor mac G5s as well as the 64 bit architecture. I would venture to guess you will at least need a G5 but you never know with Apple.

I've attached a white paper on non-Apple Quicktime H.264 for those of you who are masochists for technobable.

Christian Choi

[samsc]

This codec is amazing!

Apple will soon be releasing a groundbreaking/all definition codec for quicktime called H.264.
Christian Choi

Christian does it use interframe compression?


if it uses interframe compression it wont work so well with what we do.

[samsc]

1. Dividing each video frame into blocks of pixels so that processing of the video frame can be
conducted at the block level.
2. Exploiting the spatial redundancies that exist within the video frame by coding some of the original
blocks through transform, quantization and entropy coding (or variable-length coding).
3. Exploiting the temporal dependencies that exist between blocks in successive frames, so that only
changes between successive frames need to be encoded. This is accomplished by using motion
estimation and compensation. For any given block, a search is performed in the previously coded one
or more frames to determine the motion vectors that are then used by the encoder and the decoder to
predict the subject block.
4. Exploiting any remaining spatial redundancies that exist within the video frame by coding the
residual blocks, i.e., the difference between the original blocks and the corresponding predicted
blocks, again through transform, quantization and entropy coding.

This is the compression paradigm for h264 from the above attachment.

Note step 3.
This step - 'Exploiting the temporal dependencies that exist between blocks in successive frames, so that only
changes between successive frames need to be encoded"

this assumes that the video goes linearily and uniformly in one direction - forwards.

Not at all good for random frame access - or seemless looping between any two points in a movie.

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Crap, I knew it was too good to be true.

The preservation of color was beautiful. Do you think that it might still be a good codec to use if all videos were being played back linearly but looped?

Christian Choi

[samsc]

Crap, I knew it was too good to be true.

The preservation of color was beautiful. Do you think that it might still be a good codec to use if all videos were being played back linearly but looped?

Christian Choi

codecs that use interframe compression will work - if used in certain ways.

i mean mpeg2 works - but just not as well. and you will not get predictable playback performance.
And they wont play backwards very well. that kind of thing

[samsc]

this thing seems to be designed to do video conferencing

[samsc]

some people have started posting initial tests:

http://webpages.charter.net/bennok/video/

[litemover]

I use this codec to send 1080p presentations to my clients and the files when compressed tightly are only about 2mb in size and very high quality.

It's really a utilitarian bandwidth saving codec meant for very tight and high quality encoding but it's certainly not proccessor friendly and takes forever to encode.

The quality is only good when you encode the files with little compression. They still don't look as good as photo jpeg 75. I've also found that you can't do certain things with them such as frame grabs, they turn white. It is a revolutionary codec and has enabled Itunes to deliver movies, TV shows, and movie trailers. I myself own the entire lost series all encoded in H.264.

You can also encode your own movies and put them on your ipod using popcorn.

Christian