Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

It’s Opus, it rocks and now it’s an audio codec standard

hacks.mozilla.org

Post reply on HN
Print view View original

51–60 of 68 posts

Re: It’s Opus, it rocks and now it’s an audio codec standard

#51

Post by nullc »

AceJohnny2 wrote: post #4

I'm not familiar with Opus. Can someone tell me if it is able to dynamically adapt quality based on available bandwidth? If it loses packets in the stream, do we get a 'skip' in the audio or does the quality go down?

Yes, it's absolutely made for that, which is one of the reasons it has extreme bitrate and frame size agility. Though the decoder doesn't have a back channel to the encoder as part of the format (e.g. a duplex pair is not at all coupled by the codec and could have entirely different settings). So if you want to do rate adaptation the application will have to take care of telling the encoder that the decoder is struggling/losing frames/etc.

The codec also includes a pretty good packet loss concealer integrated, and can also use forward error correction to reduce the impact of loss.

Re: It’s Opus, it rocks and now it’s an audio codec standard

#52

Post by nullc »

azakai wrote: post #30
mtgx wrote: post #5

I expect Firefox and Chrome to adopt this within months, but IE10 is coming out soon. Does it mean it won't have it? And then we'll have to wait another year or more for IE11 to implement it? Not to mention IE9 and IE8 will probably never get it. I also assume WebM will replace Vorbis with Opus very soon?

> I expect Firefox and Chrome to adopt this within months, Firefox already adopted it (it's in nightly builds). Chrome seems to have WontFixed it, http://code.google.com/p/chromium/issues/detail?id=104241

It's actually in Firefox 15, not just nightly. People on Reddit are saying chrome's position has reversed but I don't have a link. Works in Opera already if you have gstreamer's opus plugin, and they've apparently said they'll ship it.

Re: It’s Opus, it rocks and now it’s an audio codec standard

#53

Post by hetman »

azakai wrote: post #9
wissler wrote: post #8

Earlier quoted context omitted.

There is no such thing as "unencumbered by patents". Unless you have a technology that has already been tested thoroughly in the courts, which is the only way you can really determine whether something would be deemed to violate a patent or not, you simply can't know.

Even if it was tested by the courts, you can appeal. And even after the appeal, you can appeal to a higher court, all the way to the Supreme. And even if was tested there, congress can pass a law that allows it. And even if that happens the Supreme court can strike down the law. And even if that happens, the public can mount a revolution and tear down the legal system. But, practically speaking, Opus has extremely go…

Yeah. The public is going to mount a revolution over a music format. I don't think being contrary for its own sake is helpful here.

The whole point of "tested by the courts" is that it's already gone through the appeals process. As in, you have the final decision you're going to get out of the courts.

Re: It’s Opus, it rocks and now it’s an audio codec standard

#54

Post by derleth »

wissler wrote: post #8
kibwen wrote: post #3

Before someone chimes in with that XKCD strip: How does Opus compare to other codecs? Opus is distinguished from most formats for high quality audio (AAC, Vorbis, MP3) by having low delay and it is distinguished from most low delay formats (G.711, GSM, Speex) by supporting high audio quality. It meets or exceeds existing codecs' quality across a wide range of bitrates, and it operates at lower delay than virtually an…

There is no such thing as "unencumbered by patents". Unless you have a technology that has already been tested thoroughly in the courts, which is the only way you can really determine whether something would be deemed to violate a patent or not, you simply can't know.

> There is no such thing as "unencumbered by patents".

When do the lawsuits over PNG begin?

Re: It’s Opus, it rocks and now it’s an audio codec standard

#55

Post by masklinn »

mmphosis wrote: post #32

These comments answer some questions I have concerning FLAC... starwed wrote on September 11th, 2012 at 1:29 pm: Isn’t FLAC already * open and royalty-free?* Dusk wrote on September 11th, 2012 at 1:40 pm: FLAC is a lossless codec — it typically generates output at a bitrate orders of magnitude * higher than lossless codecs such as OPUS, and there’s no way to “dial it down”.* natermer wrote on September 11th, 2012 at…

> Using low bit rate Opus may yield a 3MB file for a song, were as FLAC may end up being 150MB for the same audio.

3MB will get you POTS-quality audio though. Lossless codecs usually compress audio to half the original size (so a 150MB FLAC file — for music — will correspond to ~300MB of raw bitstream). Lossy compression to something worth listening to will usually be around 10x compression, so ~30MB for an original 300MB bitstream.

A 35mn song compressed in 3MB probably won't be worth listening to.

Re: It’s Opus, it rocks and now it’s an audio codec standard

#56

Post by iSnow »

nvmc wrote: post #41
randallu wrote: post #6

Earlier quoted context omitted.

Why would you say that? Most "hardware" decoders are DSPs that run software loaded onto them at runtime. This goes for anything with an OMAP, Tegra or Samsung (Samsung's own decode block) SoC in (that I know for sure) and probably almost everything else. Tegra3 and OMAP4 can decode WebM in hardware, for example.

I should have worded my comment better. I mean that adoption by hardware manufacturers will be slow. What's the incentive? Even for a firmware patch? MP3 is `good enough', and everyone already uses it.

Opus is royalty-free, in contrast to mp3. And it will be used in WebRTC. I can see some devices picking up Opus to support WebRTC and possibly some (not portable music players, obviously) dropping mp3.

Obviously neither you nor I have a crystal ball, but I see Opus as the PNG of audio codecs - not displacing the lousy but entrenched de-facto standard (GIF/mp3), but slowly taking over at the technological edge.

Re: It’s Opus, it rocks and now it’s an audio codec standard

#57

Post by ZeroGravitas »

wissler wrote: post #11
azakai wrote: post #9

Earlier quoted context omitted.

Even if it was tested by the courts, you can appeal. And even after the appeal, you can appeal to a higher court, all the way to the Supreme. And even if was tested there, congress can pass a law that allows it. And even if that happens the Supreme court can strike down the law. And even if that happens, the public can mount a revolution and tear down the legal system. But, practically speaking, Opus has extremely go…

No matter how many times I'm downvoted, it's still not unencumbered. It's simply not in the nature of our patent system that something this complex can be unencumbered, unless it's with respect to an expired patent. I know my position causes a lot of cognitive dissonance with people, because it implies that the system is fundamentally unfair. Well, you can either take the red or the blue pill.

I believe the system is fundamentally unfair, but also think that you are the one that's bought into their propaganda to the point that you're not thinking straight.

Particularly as you naively think that an expired patent is enough to protect you from the system.

Re: It’s Opus, it rocks and now it’s an audio codec standard

#59

Post by throwaway64 »

nullc wrote: post #49
wissler wrote: post #11

Earlier quoted context omitted.

No matter how many times I'm downvoted, it's still not unencumbered. It's simply not in the nature of our patent system that something this complex can be unencumbered, unless it's with respect to an expired patent. I know my position causes a lot of cognitive dissonance with people, because it implies that the system is fundamentally unfair. Well, you can either take the red or the blue pill.

Come on, it's only 45kloc. Do you go around insisting every non-trivial piece of software on hacker news is encumbered? And in most those cases people were not making a special effort to avoid being effectively encumbered, while Opus was.

if its a non-trivial peice of software, it almost certainly is encumbered, don't forget about idiotic patents like 1 click, there are likely millions.

Re: It’s Opus, it rocks and now it’s an audio codec standard

#60

Post by ZoFreX »

masklinn wrote: post #55
mmphosis wrote: post #32

These comments answer some questions I have concerning FLAC... starwed wrote on September 11th, 2012 at 1:29 pm: Isn’t FLAC already * open and royalty-free?* Dusk wrote on September 11th, 2012 at 1:40 pm: FLAC is a lossless codec — it typically generates output at a bitrate orders of magnitude * higher than lossless codecs such as OPUS, and there’s no way to “dial it down”.* natermer wrote on September 11th, 2012 at…

> Using low bit rate Opus may yield a 3MB file for a song, were as FLAC may end up being 150MB for the same audio. 3MB will get you POTS-quality audio though. Lossless codecs usually compress audio to half the original size (so a 150MB FLAC file — for music — will correspond to ~300MB of raw bitstream). Lossy compression to something worth listening to will usually be around 10x compression, so ~30MB for an original…

If you were using AAC (or anything else that's more advanced than MP3) a 3MB file would actually be listenable for a short song.

A 150MB FLAC file would be about 20-30 minutes long (based on a typical bitrate of 700-1000 kilobits per second).

Post reply on HN