Some questions about rtmp server channels

[scbizu]

I read the example code in example > rtmp_server_channels > main.go , but I am really confused about the meaning of delaygop waitkey framedrop delayskip cachegop ,could U add some explanation about this words ? BTW, Thanks for developing such a wonderful streaming lib ~

[scbizu]

And does joy4 support ffmpeg -s ?

[acls]

I'm fairly new to video decoding, so somebody correct me if I get anything wrong.

If you know what GOP is, then the meaning of those variables will make more sense. GOP (Group of pictures) is a collection of video frames. It starts with a key frame, which is a frame that doesn't need other frames in order to be decoded. Other non-key frames make up the changes between the key frames and rely on other frames to be decoded.

Given that description of GOP, this is what I think they mean:

• cachegop - sets the maximum number of GOPs to cache
• delaygop - seek backwards N key frames/GOPs up to the size set withcachegop
• waitkey - wait for a key frame, so that the first frame you get is a key frame. This will fix image artifacts that you would get before the key frame arrives.
• framedrop - drops every Nth frame that isn't a key frame. This will cause image artifacts until the next key frame arrives.
• delayskip - skips entire GOP if there is a delay (I'm not 100% sure if this is correct)

[scbizu]

Hi, acls .Firstly,Thanks for your explanation about the GOP,I also found it in wikipedia,I will try these options later.And have U tried to stream multiple channels ,I mean that can joy4's rtmp server solution deal with the streaming with multiple resolution,I read cgo/ffmpeg > video.go,but I do not see any implementation~ I am also new to video decoding as well as ffmpeg lol~

[acls]

As far as I know joy4 doesn't handle multiple resolutions.

[scbizu]

hmmm .. I finally use FFmpeg to do a forwarding via exec package ,However, I think it is not elegant enough at all(need ffmpeg dependency), Anyway, Thanks. @acls