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Did you write your own plugin or are you using VideoRoom or something? The thing that turned me off of Janus is that VideoRoom seemed way too high level and mad

by saurik 6y ago

Did you write your own plugin or are you using VideoRoom or something? The thing that turned me off of Janus is that VideoRoom seemed way too high level and made tons of schema assumptions, but all of the important SFU functionality seemed intertwined into the codebase of that plugin, so if I were to actually want to build a "custom solution" it looked like I would have to maintain an annoying-to-merge fork of that thick layer :/.

VWWHFSfQ 6y ago
Janus itself doesn't make any assumptions about a specific use-case. All the functionality outside of the core RTC stuff is implemented with plugins. The default "Video Room" implementation is just a Lua script [0]. Mozilla has written their own SFU plugin (in Rust) [1] for game networking that powers Mozilla Hubs [2]. [0] https://github.com/meetecho/janus-gateway/blob/master/plugins/lua/videoroom.lua https://github.com/meetecho/janus-gateway/blob/master/plugin... [1] https://github.com/mozilla/janus-plugin-sfu https://github.com/mozilla/janus-plugin-sfu [2] https://hubs.mozilla.com/#/ https://hubs.mozilla.com/#/
- saurik 6y ago
  No: the vast majority of the VideoRoom functionality is written in C, and it is where all of the actually-hard-to-do video SFU stuff -- like quality control feedback and SVC support, particularly in an end to end encryption context with all the codec-specific workarounds--is commingled together with the notion of "rooms" (which is a really awkward and specific high-level abstraction with a schema that you have to abuse for basic use cases). https://github.com/meetecho/janus-gateway/blob/master/plugins/janus_videoroom.c https://github.com/meetecho/janus-gateway/blob/master/plugin... Yes: if you don't want any of the complex video functionality, you can easily write your own Janus plugin, and that maybe sounds reasonable for some trivial game "SFU" where you are just going to move around some data channel packets... but at that point you can (and I argue should) just use libwebrtc (I do this, and I helped one of my friends do this for his product in a weekend: people act like it is hard to compile but it really isn't). (Even more so: the Lua script you linked to looks more like a demo/example of a way to use the Lua plugin to get some functionality vaguely similar to the VideoRoom plugin, and it is notably ridiculously long and contains a lot of codec-specific knowledge, while not having anywhere near the actual functionality of the actual real C VideoRoom plugin. It is as if Janus is just a super low-level WebRTC library in the form of a framework, with an explicitly monolithic plugin doing everything.)
  - VWWHFSfQ 6y ago
    It sounds like you have a use-case that you should just write your own plugin for. The out-of-the-box video room plugins aren't suitable. > the vast majority of the VideoRoom functionality is written in C It's still just a plugin that hooks the same callbacks and implements the same interfaces as any of the rest of them. Feel free to implement your own.
    - saurik 6y ago
      At that point why wouldn't I just use libwebrtc? The reason to get an off-the-shelf SFU is because all the hard work is in handling all the codec-specific workarounds, being able to handle keyframe request sharing, responding to RTCP bandwidth feedback to do SVC layer switching, and now doing all of this while most of the state is encrypted due to insertable streams... this is all hard stuff that people keep learning more about and for which the state of the art is a moving target due to browser changes. I would expect 100% of applications doing anything at all with video to want all of that functionality, but only some small number to have a "room" concept that maps to the idea of the specific schema imposed by the VideoRoom plugin. It is thereby strange that all of that general video functionality is commingled together in a 8k line C file with all of the high-level room abstraction... the answer with Janus is always "write your own plugin", but either you are doing something so trivial that Janus doesn't seem to be doing anything but the lowest level WebRTC layer, or, as far as I can tell, you have to fork the VideoRoom plugin and then hope you can merge changes from upstream back into your plugin. Am I wrong here? Like, I would love to find out I am wrong here ;P. (Which is why I was asking the OP about if their "custom solution" was a fork of VideoRoom: to see if they told me something I don't know.) But when I skim through that C file (or even the Lua file! though that demo very notably seems "incomplete" vs. the "real" C copy) I see tons of code referencing all of the codec-specific negotiation and stuff that I would explicitly be using Janus to get, so I can't not use or fork the VideoRoom plugin without losing the purpose of the platform as I would be reimplementing all of the hard parts myself (again, unless you are doing something so trivial--broadly speaking, something that doesn't involve video--that you frankly should be using libwebrtc or one of its various alternatives, such as Pion).
bbeausej 6y ago
We write our own services to coordinate janus rooms over multiple instances. That service takes care of translating from our own domain specific entities to janus room. It's also responsible for sharding rooms to healthy and available Janus instances. Instead of treating janus rooms as thick/permanent, we prefer to treat them like "just-in-time", rooms get destroyed when not used and get provisioned when requesetd, making it very flexible. We have made some modifications to the Janus video room plugin but only to fix bugs or provide specific functionality we needed for certain gaming use-cases. Out of the box, the plugin is already very featureful. The key is to always stay up to date with master, the project is fairly active and so keeping up to date is very important. We have debated writing our own plugin and that's certainly a possibility in the future. (There is a Duktape JS layer available) To be completely transparent, if we were to reach that need, I would re-evaluate the solution with more recent alternatives, like pion.ly.
- VWWHFSfQ 6y ago
  I recommend NOT implementing plugins in JavaScript with the Ducktape JS layer. I strongly recommend writing plugins in Lua for maximal compatibility and performance.
  - lminiero 6y ago
    Why's that? We wrote it to be functionally identical to the Lua plugin (the code base is the same), so engine and language apart they should behave pretty much the same way. Is there any known issue or limitation you're aware of?

by saurik 6y ago

VWWHFSfQ 6y ago

Janus itself doesn't make any assumptions about a specific use-case. All the functionality outside of the core RTC stuff is implemented with plugins. The default "Video Room" implementation is just a Lua script [0]. Mozilla has written their own SFU plugin (in Rust) [1] for game networking that powers Mozilla Hubs [2]. [0] https://github.com/meetecho/janus-gateway/blob/master/plugins/lua/videoroom.lua https://github.com/meetecho/janus-gateway/blob/master/plugin... [1] https://github.com/mozilla/janus-plugin-sfu https://github.com/mozilla/janus-plugin-sfu [2] https://hubs.mozilla.com/#/ https://hubs.mozilla.com/#/

saurik 6y ago
No: the vast majority of the VideoRoom functionality is written in C, and it is where all of the actually-hard-to-do video SFU stuff -- like quality control feedback and SVC support, particularly in an end to end encryption context with all the codec-specific workarounds--is commingled together with the notion of "rooms" (which is a really awkward and specific high-level abstraction with a schema that you have to abuse for basic use cases). https://github.com/meetecho/janus-gateway/blob/master/plugins/janus_videoroom.c https://github.com/meetecho/janus-gateway/blob/master/plugin... Yes: if you don't want any of the complex video functionality, you can easily write your own Janus plugin, and that maybe sounds reasonable for some trivial game "SFU" where you are just going to move around some data channel packets... but at that point you can (and I argue should) just use libwebrtc (I do this, and I helped one of my friends do this for his product in a weekend: people act like it is hard to compile but it really isn't). (Even more so: the Lua script you linked to looks more like a demo/example of a way to use the Lua plugin to get some functionality vaguely similar to the VideoRoom plugin, and it is notably ridiculously long and contains a lot of codec-specific knowledge, while not having anywhere near the actual functionality of the actual real C VideoRoom plugin. It is as if Janus is just a super low-level WebRTC library in the form of a framework, with an explicitly monolithic plugin doing everything.)
- VWWHFSfQ 6y ago
  It sounds like you have a use-case that you should just write your own plugin for. The out-of-the-box video room plugins aren't suitable. > the vast majority of the VideoRoom functionality is written in C It's still just a plugin that hooks the same callbacks and implements the same interfaces as any of the rest of them. Feel free to implement your own.
  - saurik 6y ago
    At that point why wouldn't I just use libwebrtc? The reason to get an off-the-shelf SFU is because all the hard work is in handling all the codec-specific workarounds, being able to handle keyframe request sharing, responding to RTCP bandwidth feedback to do SVC layer switching, and now doing all of this while most of the state is encrypted due to insertable streams... this is all hard stuff that people keep learning more about and for which the state of the art is a moving target due to browser changes. I would expect 100% of applications doing anything at all with video to want all of that functionality, but only some small number to have a "room" concept that maps to the idea of the specific schema imposed by the VideoRoom plugin. It is thereby strange that all of that general video functionality is commingled together in a 8k line C file with all of the high-level room abstraction... the answer with Janus is always "write your own plugin", but either you are doing something so trivial that Janus doesn't seem to be doing anything but the lowest level WebRTC layer, or, as far as I can tell, you have to fork the VideoRoom plugin and then hope you can merge changes from upstream back into your plugin. Am I wrong here? Like, I would love to find out I am wrong here ;P. (Which is why I was asking the OP about if their "custom solution" was a fork of VideoRoom: to see if they told me something I don't know.) But when I skim through that C file (or even the Lua file! though that demo very notably seems "incomplete" vs. the "real" C copy) I see tons of code referencing all of the codec-specific negotiation and stuff that I would explicitly be using Janus to get, so I can't not use or fork the VideoRoom plugin without losing the purpose of the platform as I would be reimplementing all of the hard parts myself (again, unless you are doing something so trivial--broadly speaking, something that doesn't involve video--that you frankly should be using libwebrtc or one of its various alternatives, such as Pion).

bbeausej 6y ago

We write our own services to coordinate janus rooms over multiple instances. That service takes care of translating from our own domain specific entities to janus room. It's also responsible for sharding rooms to healthy and available Janus instances. Instead of treating janus rooms as thick/permanent, we prefer to treat them like "just-in-time", rooms get destroyed when not used and get provisioned when requesetd, making it very flexible. We have made some modifications to the Janus video room plugin but only to fix bugs or provide specific functionality we needed for certain gaming use-cases. Out of the box, the plugin is already very featureful. The key is to always stay up to date with master, the project is fairly active and so keeping up to date is very important. We have debated writing our own plugin and that's certainly a possibility in the future. (There is a Duktape JS layer available) To be completely transparent, if we were to reach that need, I would re-evaluate the solution with more recent alternatives, like pion.ly.

VWWHFSfQ 6y ago
I recommend NOT implementing plugins in JavaScript with the Ducktape JS layer. I strongly recommend writing plugins in Lua for maximal compatibility and performance.
- lminiero 6y ago
  Why's that? We wrote it to be functionally identical to the Lua plugin (the code base is the same), so engine and language apart they should behave pretty much the same way. Is there any known issue or limitation you're aware of?