Cisco's Open Source H.264 Codec

by pcl • 13 years ago

182 82 13 years ago

lawl• 13 years ago

It would be really cool if they provided predictable builds, then we could just compare the binary against a self-compiled binary and be sure tehre are no backdoors we can't see in the code.

Sadly even truecrypt fails to provide that. So i guess we'll have to life with binary blobs no one knows what they're really doing.

cfluffy6• 13 years ago

Hi, I'm one of the people working on the stuff Cisco open sourced and yes, it will be predictable and verifiable builds. We are working with some of the Mozilla folks to make sure we can do that.

cpeterso• 13 years ago

How often do you expect new Cisco builds to be published? Will the releases be versioned so Firefox version X knows it will always install OpenH264 version Y from Cisco's binary blob server?

atonse• 13 years ago

I'm genuinely curious --- how come nobody thought of doing this (being some kind of platinum member and just putting it out there for all to use) all these years during the fighting about h.264 vs the open web and yada yada?

What Cisco did seems to have put an end to all those debates, and h.264 is available for all, with patents intact, etc.

samspenc• 13 years ago

It costs Cisco $6 million a year to do this. I wonder if any of the beneficiaries (Firefox, etc) are pitching in.

That sounds like loose change, but probably stuck up in bureaucratic decision-making at anyone who thought of this before. ("Why are we spending $6 million a year to make it free for everyone else again?")

EDIT/UPDATE: In the second paragraph, I was referring to other companies and why they didn't do this earlier. It clearly brings Cisco quite a bit of goodwill to do this, and to see more video flowing on the web.

pkaye• 13 years ago

I doubt it costs Cisco anything extra because they probably need the distribution rights for other products they develop (for example WebEx.) Besides it a good PR benefit for them with minimal incremental cost.

indrax• 13 years ago

Cisco benefits from video on the internet being a big thing.

pslam• 13 years ago

No, it hasn't put an end to debate at all. This is an ugly workaround and still requires Cisco to build binaries on your behalf. It's quite a stretch of "open" and certainly not "free" (not that it claims to be).

There is still ongoing work to create a better, free standard.

mlinksva2• 13 years ago

VP8 exists, and is free

VP9 exists, is better and free (in Chrome, will be in Firefox release in a few months)

There is still ongoing work to create a better, encumbered codec, h.265

There is going work to create a much better, free codec, Dalaa

Now is a good time to finally break free of encumbered video codecs. If not now, when. :)

wmf2• 13 years ago

Fluendo does this with MP3, but that license is only $50K instead of millions.

People proposed this idea repeatedly to Mozilla back in the day but they rejected it. Maybe they feel their hands are somehow cleaner if Cisco is paying instead of them.

gcb12• 13 years ago

moz would have to foot the 6mi.

cisco pays 6mi, and them mpegla returns 3mi to them for their patents in the pool. and if the format becomes ubiquitous, they get any few billions from this same pool from their competitors when they also license it.

they are still the bad guy in this.

technomancy2• 13 years ago

"Free as in as long as you don't try to compile your own."

If you think that addresses the issues at play, you haven't been paying attention to both sides of the debate.

sliverstorm3• 13 years ago

Open source does not mean free to build & use. It means open source.

anon4• 13 years ago

Why can't they just build ffmpeg (with only h.264 enabled), instead of their own implementation of h.264?

Sanddancer2• 13 years ago

ffmpeg is lgpl-encumbered. Openh264 is under the much more open BSD license.

sliverstorm3• 13 years ago

I'm still confused why Cisco is even allowed to do this. Do they pay a flat license fee to MPEG-LA for unlimited usage? I would think they would pay per-seat like most video codecs.

garblegarble• 13 years ago

It is, but there's a cap of $6.5M/year (and they'd get some of that back as payment for their patents in the pool)

crbnw00ts• 13 years ago

There sure are a lot of hard-coded numbers in that codebase. In many cases it's easy to figure out where the numbers came from, but in others, it's nearly inscrutable without a named constant or a comment or something. Here's one example:

https://github.com/cisco/openh264/blob/master/codec/encoder/...

Where does "15" come from? I suppose if I'd written a codec like this before, or if I stared at the code long enough, I could figure it out, but wouldn't it be better to use an enum or a #define?

tetrep• 13 years ago

while i'm sure there's many other examples, in that particular case it's just the maximum value of an unsigned 8 bit integer, as defined above on line 1252.

it would be a bit better if it explicitly had a nice #define but recognizing the values of common powers of two (minus one) is a useful code reading skill.

josephlord8• 13 years ago

I think you mean 4bit.

matthewmacleod• 13 years ago

Huh. I don't think it's just you - that looks like some properly nasty code. Formatting is all over the place, lines are commented out, comments are useless and obviously wrong in places...

I don't really speak C++ though, so maybe this is normal.

nly2• 13 years ago

It's not because it's C++... this is just really ugly code.

_wmd2• 13 years ago

Encountered this topic recently in the office.. I'm from the side of the fence that doesn't overly care about code tidyness, so long as it performs its overall function. 10 years ago this kind of thing might have bothered me a lot more, but at some point crossed a threshold where I realized _all code generated to the present day_ is pretty ugly and long term unmaintainable (but that's a story for a rather large and rather boring essay).

The tl;dr is simply that if you obsess over minor details on this level, a lot of brainpower is wasted that could be used for bigger problems you should be much more worried about.

Playing devil's advocate, in this case the if() is obviously a guard for the subsequent switch. Moving just the constant '15' into a #define would make it read more like some magical sentinel value, unless you also #defined all the literal values used in the switch, at which point you've introduced a wholly bullshit layer of abstraction to what was otherwise incredibly concrete and explicit code.

Let's assume you have a great reason for doing that. OK. So what do you call these constants? Well, the code appears to be branching to special cases based on the width of some integer. So we instead have what, WIDTH_1_BIT, WIDTH_2_BITS, ..., WIDTH_15_BITS? Now we've pulled those constants out, you stare at the block of #defines, and think, damn, this is so ugly since most of the value space isn't fully defined! So some kindly maintenance programmer comes along and pads out the rest, producing a perfectly beautiful block of utter line noise.

That is arguably considerably less readable than what we started with

hughlomas• 13 years ago

A simple //comment would have sidestepped all of that and still clarified the number's purpose.

Groxx• 13 years ago

I'm not sure how much this applies to open source. Closed source, quite possibly, since it probably won't survive long enough / need to change enough / need enough people to understand it.

Open source, meanwhile, requires being understandable to new people. It needs to explain itself, or it needs to be idiomatic (within its specialty). If neither, you're condemning people to rewrite it or waste time trying to figure out the original intent.

vinkelhake• 13 years ago

Your first paragraph sounds quite defeatist. In my experience, the way you deal with "minor details" is to write them down in a style guide. It'll take away a lot of the quibbling about small things. Some will find it limiting, others will find it liberating.

I've worked at several jobs that had decade old code in production. Some cared about the little things, some didn't. I know which code was the best to work with. In my experience, the broken windows theory is true when it comes to code. The little things matter in the long run.

ChuckMcM• 13 years ago

As with many things it seems like knowing how an H264 codec works before reading the code is essential. I don't someone has an approachable reference for the standard?

andrewf• 13 years ago

IMO it doesn't make sense to read code like this without a copy of the H.264 spec in hand. And once you've got that spec, why paraphrase a fraction of it, poorly, in the source code?

I do think that comments at the function level indicating which part of the spec you should be reading would be nice. They might not be an issue for people who are indoctrinated into the code though.

baq• 13 years ago

// spec 12.3.4.5

would certainly help if you had a spec open.

Daiz2• 13 years ago

Constrained Baseline Profile up to Level 5.2 (4096x2304)

Well, I wasn't expecting miracles from this, but constrained baseline profile only? That's very disappointing. Not only will this be unable to decode most of the H.264 content out there (web and otherwise), you could very likely get better results with VP8.

If only they'd have endorsed something like libavcodec instead...

leetrout• 13 years ago

Seriously... So much for adaptive bit rate.

Makes sense that Cisco would be using CBP after seeing this on Wikipedia:

"this profile is most typically used in videoconferencing and mobile applications"

http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Profiles

Daiz2• 13 years ago

Makes sense that Cisco would be using CBP

Yes, I can understand the encoder only supporting CBP - videoconferencing is the one thing that you really need encoding capabilities for in a browser. Anything else you can basically always encode offline and use x264 or whatever.

The real shortcoming is the fact that the decoder is also limited to CBP - as I said, this makes it completely useless for decoding most H.264 video out there (which is either Main or High Profile, generally the latter if we're talking HD content), web or otherwise.

espadrine• 13 years ago

The real challenge for Cisco is to play well with contributors.

While initially, members of the project seemed to be from the same Cisco family, it looks welcoming: https://github.com/cisco/openh264/blame/master/CONTRIBUTORS

est2• 13 years ago

https://github.com/cisco/openh264/blob/master/CONTRIBUTORS

Contributors are 100% Chinese. Is this project make in Cisco China R&D?

general_failure• 13 years ago

Cullen Jennings is not chinese

est2• 13 years ago

Well, when I posted the comment it was like this

https://github.com/cisco/openh264/blob/3747f562492ea301b84e3...

view history here

https://github.com/cisco/openh264/commits/master/CONTRIBUTOR...

who8mylunch2• 13 years ago

What about x264 hosted at VideoLAN: http://www.videolan.org/developers/x264.html? It's open source and people have implemented tons of cool software tools with it.

dpe822• 13 years ago

The key here is Cisco is paying the patent royalties for anyone who uses their codec binaries - which will cost them $6.5m/year. They could do the same for x264, but it's probably legally safer to distribute an implementation they wrote themselves.

who8mylunch2• 13 years ago

Thanks for the classification. I was not aware of those costs.

cfluffy6• 13 years ago

If the x264 people think they can give x264 to Cisco under a license that we can compile it and distribute the binaries with no changes to our MPEG LA licensing agreements, tell them to get talk of me (fluffy@cisco.com) if they want to do this. I came to the conclusion Cisco could not do this without x264 giving us an appropriate license.

Florin_Andrei2• 13 years ago

Works great. You can put 3 hours of 1080p24 content on a single layer DVD (4.4 GB) and it still looks great. And there's room left for a soundtrack too.

MrBuddyCasino• 13 years ago

Well it looks ok, but lots of detail is lost, especially if the source is grainy. I usually don't bother and go for 720p, but when you need great quality, you need 8-12GB for 1080p.

Sanddancer2• 13 years ago

Among other reasons, x264 is GPL-encumbered, which would make it impossible to bundle with the sorts of projects that openh264 is going to be bundled with.

ZeroGravitas3• 13 years ago

It's actually dual-licenced GPL and an alternative where you don't get the so-called "viral" properties of the GPL, but changes to the code still get returned to the project, kind-of LGPL-ish.

http://x264licensing.com/

That seems to suit what Cisco are doing here, but a Cisco representative claimed that when they suggested just using x264 that it was shot down by Mozilla (possibly because Mozilla shared the common misconception than x264 is GPL-only?)

alister• 13 years ago

The license is abundantly generous -- it essentially says, "do whatever you want, but don't hold Cisco responsible".

But this isn't the whole story. There are also patents involved, and these are not mentioned in the LICENSE file.

Cisco does explain the issue on a different website: "a team can choose to use the source code, in which case the team is responsible for paying all applicable license fees, or the team can use the binary module distributed by Cisco, in which case Cisco will cover the MPEG LA licensing fees [1]" (where MPEG LA, or MPEG Licensing Authority, is the organization that holds the patents and of which Cisco is a member)

I think that most of the audience here seems to know all this. But it wasn't clear to me, and I think it probably wouldn't be obvious to many other readers.

[1] http://www.openh264.org/faq.html

_rmp_• 13 years ago

can anyone confirm that in order to avoid MPEG LA license fees for encoding (20$ per unit sold I think) I can not distribute Cisco's compiled encoder library with my software (even if I use the binary from Cisco's repository -when they make it available- instead of compiling it myself) and the only option would be to download it from my software at runtime as a plugin? are there any other options (the systems on which my software is going to be installed do not have internet access)?

mcpherrinm• 13 years ago

That's right. This is a workaround for the MPEG LA license, and having the user download the binary right from Cisco is the only way to have Cisco pay for the license fees. Anything else and you've got to become a licensee.

josephlord8• 13 years ago

Not $20 but $0.20. (after the first free 100,000 and until it drops to $0.10 after 5 million) although you may have to sign a license with MPEG-LA to take advantage of the free 100,000 and potentially submit to audits so there are risks/costs.

I don't know how direct the distribution from Cisco to the end user has to be to be legal although I can imagine a range of possibilities for this I don't know if they would be practical in your situation. I imagine that you could ship a tool that creates an install package to be used on the non-connected devices and downloads the binary from Cisco and adds it to your install bundle but that is still an annoying extra step.

Practically I don't see anyone coming after you (and certainly not getting real damages) if you did include Cisco's binary with your product - it would be hard to see the real harm or damage caused.

Cisco's Open Source H.264 Codec

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