Or speex narrowband or others. I think the tendency to pick Opus is just because it has a newer date on it -- its design goals were not necessarily to optimize for low bitrate; Opus just happened to still sound OK when the knob was turned down that far.
One other point I intended to make that is not reflected in many listening/comparison tests offered by these presentations -- in the typical applications of low bitrate codecs, they absolutely must be able to gracefully degrade. We see Mlow performing at 6kbps here; how does it perform with 5% bit errors? Can it be tuned for lower bitrates like 3kpbs? A codec with a 6kbps floor that garbles into nonsense with a single bit flip would be dead-on-arrival for most real world applications. If you have to double the bitrate with FEC to make it reliable, have you really designed a low bitrate codec? The only example we heard of mlow was 30% loss on a 14kbps stream = 9.8kbps. Getting 6kbps through such a channel is a trivial exercise.
My understanding was Opus was specifically developed with the idea of replacing both Speex and Vorbis. "Better quality than Speex" is literally one of their selling points, so I'd be interested to hear more details.
Lyra goes against the design goals of MLow though, by using machine learning techniques, and thus possibly not running on the devices that Meta is targeting with MLow.
Google claims SoundStream can run on low-end devices, though, so indeed I would like Meta to show that it still doesn't work well enough for their usecase. Specifically, I would like to know if it's possible to get SoundStream running in very old Android versions in low end devices, before a lot of APIs related to NNs in Android came around.
gorkish|1 year ago
One other point I intended to make that is not reflected in many listening/comparison tests offered by these presentations -- in the typical applications of low bitrate codecs, they absolutely must be able to gracefully degrade. We see Mlow performing at 6kbps here; how does it perform with 5% bit errors? Can it be tuned for lower bitrates like 3kpbs? A codec with a 6kbps floor that garbles into nonsense with a single bit flip would be dead-on-arrival for most real world applications. If you have to double the bitrate with FEC to make it reliable, have you really designed a low bitrate codec? The only example we heard of mlow was 30% loss on a 14kbps stream = 9.8kbps. Getting 6kbps through such a channel is a trivial exercise.
DragonStrength|1 year ago
why_only_15|1 year ago
they also address something similar in the body: "Here are two audio samples at 14 kbps with heavy 30 percent receiver-side packet loss."
cvg|1 year ago
doodlesdev|1 year ago
Google claims SoundStream can run on low-end devices, though, so indeed I would like Meta to show that it still doesn't work well enough for their usecase. Specifically, I would like to know if it's possible to get SoundStream running in very old Android versions in low end devices, before a lot of APIs related to NNs in Android came around.