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would probably like to avoid the expense involved in not only finding and/or designing a Theora decoder Not to mention H.264 was designed with hardware decodin

by trezor 17y ago

would probably like to avoid the expense involved in not only finding and/or designing a Theora decoder Not to mention H.264 was designed with hardware decoding in mind, while Ogg Theora was not. From reddit: http://www.reddit.com/r/programming/comments/8yhi6/decoding_the_html_5_video_codec_debate_why/c0aum5a http://www.reddit.com/r/programming/comments/8yhi6/decoding_... Theora is derived from VP3 and neither were designed with hardware implementations in mind. VP3 uses funky high precision unsigned multiplication because it was fast on a Pentium II MMX back in the day. Theora carries this over and it makes hardware implementation a pain in the arse and virtually unimplementable in some cases ... H.264 was specifically designed with hardware implementation in mind and is thus pure 16-bit mathematics, at least through to Main Profile. It would seem that for the embedded market, Theora is not going to happen anytime soon.

ZeroGravitas 17y ago
I'm not an expert, but I'm dubious about that comment. For starters "designed with hardware implementations in mind" is a double edged sword. It seems to me that H.264 used this as a crutch to a degree that maybe only makes sense if selling decoding chips is part of your revenue stream. But it appears that even "hardware" implementations of H.264 don't even use ASICs anymore. They just use a seperate, but generic, chip with DSP. It's sometimes treated as a hardware black box by the rest of the system but inside it's software: http://lwn.net/Articles/337101/ http://lwn.net/Articles/337101/ There's an OMAP version of Theora being built right now, (sponsored by Mozilla I tihnk) but I can't find the link right now. That should reset people's expectations somewhat in this regard.
- ZeroGravitas 17y ago
  Here's a planning discussion from a few months ago on Fennec (aka Firefox Mobile) and it's support of the Video tag http://archive.netbsd.se/?ml=mozilla-dev-planning&a=2009-04&t=10284220 http://archive.netbsd.se/?ml=mozilla-dev-planning&a=2009... There's a summary post at the very end which says, Theora on portable hardware with DSP acceleration is very doable, and that they have a suitably qualified volunteer to do it. "On performance: * Right now we're getting 1-2fps with decoding video (wasn't sure what size, though?) * Some people on the call had done testing and it's possible to do 24fps at VGA resolution of Theora decoding, not including YUV -> RGB conversion and without the painting overhead. This was on a 200mhz ARM chip. So we know it can go fast. * It's very possible to port that decoding code to a DSP chip - someone did it at broadcom and was able to get 720p decoding at full speed on a 125mhz DSP chip. So we know this is possible. * In theory because of the design of Theora we should be able to do better than H.264 in terms of performance and be able to match on power consumption as well. " Here is a mail confirming that the work is underway: http://www.mail-archive.com/whatwg@lists.whatwg.org/msg15730.html http://www.mail-archive.com/whatwg@lists.whatwg.org/msg15730...

by trezor 17y ago

ZeroGravitas 17y ago

I'm not an expert, but I'm dubious about that comment. For starters "designed with hardware implementations in mind" is a double edged sword. It seems to me that H.264 used this as a crutch to a degree that maybe only makes sense if selling decoding chips is part of your revenue stream. But it appears that even "hardware" implementations of H.264 don't even use ASICs anymore. They just use a seperate, but generic, chip with DSP. It's sometimes treated as a hardware black box by the rest of the system but inside it's software: http://lwn.net/Articles/337101/ http://lwn.net/Articles/337101/ There's an OMAP version of Theora being built right now, (sponsored by Mozilla I tihnk) but I can't find the link right now. That should reset people's expectations somewhat in this regard.

ZeroGravitas 17y ago
Here's a planning discussion from a few months ago on Fennec (aka Firefox Mobile) and it's support of the Video tag http://archive.netbsd.se/?ml=mozilla-dev-planning&a=2009-04&t=10284220 http://archive.netbsd.se/?ml=mozilla-dev-planning&a=2009... There's a summary post at the very end which says, Theora on portable hardware with DSP acceleration is very doable, and that they have a suitably qualified volunteer to do it. "On performance: * Right now we're getting 1-2fps with decoding video (wasn't sure what size, though?) * Some people on the call had done testing and it's possible to do 24fps at VGA resolution of Theora decoding, not including YUV -> RGB conversion and without the painting overhead. This was on a 200mhz ARM chip. So we know it can go fast. * It's very possible to port that decoding code to a DSP chip - someone did it at broadcom and was able to get 720p decoding at full speed on a 125mhz DSP chip. So we know this is possible. * In theory because of the design of Theora we should be able to do better than H.264 in terms of performance and be able to match on power consumption as well. " Here is a mail confirming that the work is underway: http://www.mail-archive.com/whatwg@lists.whatwg.org/msg15730.html http://www.mail-archive.com/whatwg@lists.whatwg.org/msg15730...