Just a interesting question about dropped frames and delay.

[josephlenis]

I work doing streams for various events, I'm currently having a conversation with someone that streams as well, I told him that I noticed that when you have a lot of dropped frames your stream has more delay than normal, or at least that is what I noticed on twitch, he told me that's imposible because everytime stream gets synced... but is this like this? Does dropping frames add more delay? or it doenst affect the delay at all? pls help me with the information about this...

 

[qhobbes]

What are dropped frames and why do they happen?

What are dropped frames and why do they happen? GitHub Gist: instantly share code, notes, and snippets.

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Dropping frames doesn't cause delay, it's the result of delay.

 

[FerretBomb]

I work doing streams for various events, I'm currently having a conversation with someone that streams as well, I told him that I noticed that when you have a lot of dropped frames your stream has more delay than normal, or at least that is what I noticed on twitch, he told me that's imposible because everytime stream gets synced... but is this like this? Does dropping frames add more delay? or it doenst affect the delay at all? pls help me with the information about this...

Dropping frames doesn't cause delay, it's the result of delay.

Actually, the streamer dropping frames DOES cause additional delay on the viewer end. As the stream is unstable, the Twitch video infrastructure will require buffering more video chunks in an attempt to provide smooth playback. If the streamer keeps dropping frames, that delay will continue to grow.
This can happen as a result of a poor connection between the viewer and Twitch's video delivery servers (the video player buffering additional video chunks), but it also can occur on the ingest and replication side of things, which follows downhill to the video player.

The video player doesn't care why it ran out of video chunks to play, it just says 'give me more, and increase the local buffer'.

This occurs on a per-viewer basis though. The fix is to refresh the page, which will also refresh the video player and reset its buffer. That said, the Twitch video player IS pseudo-smart; it tries to speed up playback subtly if the connection smooths out, to 'catch up' playback and get it closer to realtime. This can cause audio warbling... not normally noticeable in human voices, but VERY obvious and distinct with things like music where the notes 'flutter' or sound off-key.

 

[josephlenis]

Actually, the streamer dropping frames DOES cause additional delay on the viewer end. As the stream is unstable, the Twitch video infrastructure will require buffering more video chunks in an attempt to provide smooth playback. If the streamer keeps dropping frames, that delay will continue to grow.
This can happen as a result of a poor connection between the viewer and Twitch's video delivery servers (the video player buffering additional video chunks), but it also can occur on the ingest and replication side of things, which follows downhill to the video player.

The video player doesn't care why it ran out of video chunks to play, it just says 'give me more, and increase the local buffer'.

This occurs on a per-viewer basis though. The fix is to refresh the page, which will also refresh the video player and reset its buffer. That said, the Twitch video player IS pseudo-smart; it tries to speed up playback subtly if the connection smooths out, to 'catch up' playback and get it closer to realtime. This can cause audio warbling... not normally noticeable in human voices, but VERY obvious and distinct with things like music where the notes 'flutter' or sound off-key.

That means that this "delay" only happens when streaming to twitch? I'm having an evenet and streaming it on Vimeo, this wont happen if the stream drop frames?

 

[FerretBomb]

That means that this "delay" only happens when streaming to twitch? I'm having an evenet and streaming it on Vimeo, this wont happen if the stream drop frames?

That depends on how Vimeo handles their video player and buffering. I do not use Vimeo, so have no knowledge if their player operates the same way. But it probably does, so probably will.
The best solution is to fix your network problem so you don't drop frames.

Note that even if your connection is perfect, if the viewer's connection has an issue, they may still have increasing delay if Vimeo's video player operates the same way.

 

[josephlenis]

That depends on how Vimeo handles their video player and buffering. I do not use Vimeo, so have no knowledge if their player operates the same way. But it probably does, so probably will.
The best solution is to fix your network problem so you don't drop frames.

Note that even if your connection is perfect, if the viewer's connection has an issue, they may still have increasing delay if Vimeo's video player operates the same way.

Thanks for the info, I'll have this on mind, and if more ppl have extra details I would appreciate the info :)