4 ms·

In my case, zoom has a killer feature that skype and google don't have. Zoom can be told to use a codec which isn't optimized for voice (referred to as "preserv

In my case, zoom has a killer feature that skype and google don't have. Zoom can be told to use a codec which isn't optimized for voice (referred to as "preserve original sound"). Specifically, I have weekly lessons on my instrument, and it was just a horrible, garbled experience attempting to play instruments to each other.

bscphil 7y ago
Aren't WebRTC calls mostly using Opus? If they enable a reasonable audio bitrate (64 kbps+) when the bandwidth is available, you should be able to get quite decent music quality. Certainly, this should always be enabled for video calls because it would be a small fraction of the total call bitrate. (Of course, these are theoretical considerations, not a prediction for what actually happens in practice.)
- user5994461 7y ago
  It's 128 kbps to have music quality almost indistinguishable from a music CD. Maybe the latest codecs can do something decent with 96 kbps, not sure. 64 kpbs, whichever codec, gets this small by cutting all frequencies outside of human speech. It cannot record instrumental sounds well.
  - bscphil 7y ago
    > 64 kpbs, whichever codec, gets this small by cutting all frequencies outside of human speech Unfortunately, you're completely wrong about this. Sorry to undeceive you, I would have said the same a few years ago. Codecs, especially the best AAC encoders, and Opus, have improved drastically since 2005. Listen for yourself to 64 kbps music samples made with the 2011 Opus. They're quite passable. https://people.xiph.org/~greg/opus/ha2011/ https://people.xiph.org/~greg/opus/ha2011/ Certainly good enough for a WebRTC stream. No, it's not close to transparent, but it's going to be fine for a music lesson, there's no weird pitch shifts or anything.
    - user5994461 7y ago
      Won't believe it till I see the benchmarks. Now trying to find some links comparing to MP3 and AAC. I'd really love to find out that codecs have halved audio size in the past half decade. To be clear, I mean quality indistinguishable from an audio CD, listening to songs in the quiet living room. I am not talking good enough for a stream or a phone call, that's a much lower bar. For historic reference. Steam changed the codec for their voice chat around 2011 to something called SILK that seemed to be the parent of OPUS. It gave just enough quality to blast Ievan Polkka and Britney Spears in team fortress games and other players could recognize the song (noting it's very very low bitrate, it ain't great). By comparison, the previous encoding couldn't play songs at all, it butchered most frequencies so much that the audio was just lost.
      - bscphil 7y ago
        > SILK that seemed to be the parent of OPUS That's right - SILK was a codec tuned for voice chat, not music. CELT is the other parent of OPUS and is tuned for music. (Opus uses a hybrid strategy that switches between codecs as necessary.) Don't just look at the benchmarks, at the bottom of the page you can click on the links and listen to a bunch of 64 kbps Opus samples. They're very, very good. And no, they aren't indistinguishable from a CD. As I said in the original comment, they're more than good enough for high quality music streaming for a video chat. > I'd really love to find out that codecs have halved audio size in the past half decade. This has happened, to my ears at least. A little over a decade ago, I could not-infrequently tell a V2 MP3 (~196 kbps) from the FLAC. Took 256 kbps (~V0) to be reliably transparent. (I think it's improved marginally since then, V2 might be transparent almost all the time now.) These days, it's quite infrequent I can tell a 128 kbps Opus file from the FLAC. And the best codecs are quite passable even at 64 kbps. Actually, Opus is "okay" even down to like 48 kbps. Try the sample here: https://people.xiph.org/~jm/opus/opus-1.2/ https://people.xiph.org/~jm/opus/opus-1.2/
Orphis 7y ago
It's NOT about the codec. It's about all the post-processing happening to do noise cancellation, echo removal or auto gain. Those features are usually configurable in major video conferencing apps. FYI, I saw some artist play on Zoom not so long ago, and the music was muted by their client. And they didn't know it happened or how to fix it. No software is immune from misconfiguration.

bscphil 7y ago

Aren't WebRTC calls mostly using Opus? If they enable a reasonable audio bitrate (64 kbps+) when the bandwidth is available, you should be able to get quite decent music quality. Certainly, this should always be enabled for video calls because it would be a small fraction of the total call bitrate. (Of course, these are theoretical considerations, not a prediction for what actually happens in practice.)

user5994461 7y ago
It's 128 kbps to have music quality almost indistinguishable from a music CD. Maybe the latest codecs can do something decent with 96 kbps, not sure. 64 kpbs, whichever codec, gets this small by cutting all frequencies outside of human speech. It cannot record instrumental sounds well.
- bscphil 7y ago
  > 64 kpbs, whichever codec, gets this small by cutting all frequencies outside of human speech Unfortunately, you're completely wrong about this. Sorry to undeceive you, I would have said the same a few years ago. Codecs, especially the best AAC encoders, and Opus, have improved drastically since 2005. Listen for yourself to 64 kbps music samples made with the 2011 Opus. They're quite passable. https://people.xiph.org/~greg/opus/ha2011/ https://people.xiph.org/~greg/opus/ha2011/ Certainly good enough for a WebRTC stream. No, it's not close to transparent, but it's going to be fine for a music lesson, there's no weird pitch shifts or anything.
  - user5994461 7y ago
    Won't believe it till I see the benchmarks. Now trying to find some links comparing to MP3 and AAC. I'd really love to find out that codecs have halved audio size in the past half decade. To be clear, I mean quality indistinguishable from an audio CD, listening to songs in the quiet living room. I am not talking good enough for a stream or a phone call, that's a much lower bar. For historic reference. Steam changed the codec for their voice chat around 2011 to something called SILK that seemed to be the parent of OPUS. It gave just enough quality to blast Ievan Polkka and Britney Spears in team fortress games and other players could recognize the song (noting it's very very low bitrate, it ain't great). By comparison, the previous encoding couldn't play songs at all, it butchered most frequencies so much that the audio was just lost.
    - bscphil 7y ago
      > SILK that seemed to be the parent of OPUS That's right - SILK was a codec tuned for voice chat, not music. CELT is the other parent of OPUS and is tuned for music. (Opus uses a hybrid strategy that switches between codecs as necessary.) Don't just look at the benchmarks, at the bottom of the page you can click on the links and listen to a bunch of 64 kbps Opus samples. They're very, very good. And no, they aren't indistinguishable from a CD. As I said in the original comment, they're more than good enough for high quality music streaming for a video chat. > I'd really love to find out that codecs have halved audio size in the past half decade. This has happened, to my ears at least. A little over a decade ago, I could not-infrequently tell a V2 MP3 (~196 kbps) from the FLAC. Took 256 kbps (~V0) to be reliably transparent. (I think it's improved marginally since then, V2 might be transparent almost all the time now.) These days, it's quite infrequent I can tell a 128 kbps Opus file from the FLAC. And the best codecs are quite passable even at 64 kbps. Actually, Opus is "okay" even down to like 48 kbps. Try the sample here: https://people.xiph.org/~jm/opus/opus-1.2/ https://people.xiph.org/~jm/opus/opus-1.2/

Orphis 7y ago

It's NOT about the codec. It's about all the post-processing happening to do noise cancellation, echo removal or auto gain. Those features are usually configurable in major video conferencing apps. FYI, I saw some artist play on Zoom not so long ago, and the music was muted by their client. And they didn't know it happened or how to fix it. No software is immune from misconfiguration.