Duplex Stream between a MacBook Air and a Win PC - Skipping lots of frames

[ygreq]

Hi folks!

I am trying to figure out what to change so that I can have a duplex stream between 2 pcs (one mac and one windows) sending the webcams to each other practically making a video chat. The problem is that the video displayed on the PC is skipping a lot of frames, sometimes showing 1 frame per multiple seconds. The video shown on the Macbook Air is pretty decent. So I am trying to figure out how to improve the script sent from the Macbook Air. I tried changing the codec, but that does not help.

This is the code I used for the Win PC. uv -t dshow:device=4:mode=0:RGB -c libavcodec:codec=H.264 -d gl:d 192.168.1.106
And this is the code I used in the Terminal for the MacBook Air ./uv -t avfoundation:device=0:mode=0:fps=30 -c libavcodec:codec=H.264 -d multiplier:gl#preview 192.168.1.104
I also tried using the UV.app

The Macbook Air is a bit old from 2013 and it is an Air after all. But I am wondering is the problem lies somewhere else.
Any suggestions?
Thank you!

For the H264, this is the errors I get on the PC:

[video dec.] Detected internal codec: UYVY
[video dec.] Successfully reconfigured display to 640x480 @30.00p, codec UYVY
[lavd] Using decoder: h264
[video dec.] New incoming video format detected: 640x480 @29.97p, codec H.264
[lavd] Using decoder: h264
[h264 @ 00000000073ef180] decode_slice_header error
[h264 @ 00000000073ef180] decode_slice_header error
[h264 @ 00000000073ef180] decode_slice_header error
[h264 @ 00000000073ef180] decode_slice_header error
[h264 @ 00000000073ef180] no frame!
[lavd]  Error while decoding frame (rc == -1094995529): Invalid data found when processing input.

I also tried using MJPEG on MacBook Air. This is what I get:

[video dec.] Detected internal codec: UYVY
[video dec.] Successfully reconfigured display to 640x480 @29.97p, codec UYVY
[lavd] Warning: JPEG decoder will use full-scale YUV.
[lavd] Using decoder: mjpeg
Setting GL window size 640x480 (640x480).
[video dec.] New incoming video format detected: 640x480 @30.00p, codec MJPEG
[lavd] Warning: JPEG decoder will use full-scale YUV.
[lavd] Using decoder: mjpeg
[lavd]  Error while decoding frame (rc == -22): Invalid argument.
[video dec.] Detected internal codec: UYVY
[video dec.] Successfully reconfigured display to 640x480 @30.00p, codec UYVY
[lavd] Warning: JPEG decoder will use full-scale YUV.
[lavd] Using decoder: mjpeg
[video dec.] New incoming video format detected: 640x480 @29.97p, codec MJPEG
[lavd] Warning: JPEG decoder will use full-scale YUV.
[lavd] Using decoder: mjpeg
[lavd]  Error while decoding frame (rc == -22): Invalid argument.
[video dec.] New incoming video format detected: 640x480 @0m[video dec.] Detected internal codec: UYVY
30.00p, codec MJPEG
[video dec.] Successfully reconfigured display to 640x480 @30.00p, codec UYVY
[lavd] Warning: JPEG decoder will use full-scale YUV.
[lavd] Using decoder: mjpeg
Setting GL window size 640x480 (640x480).
[video dec.] New incoming video format detected: 640x480 @29.97p, codec MJPEG
[video dec.] Successfully reconfigured display to 640x480 @29.97p, codec UYVY

[MartinPulec]

Hi,

(just FYI -d multiplier:gl#preview is useless unless you use GUI, you can just use -d gl). Anyways, I think that the problem may be continuous switching from 29.97p to 30.00p and back - can you confirm that it occurs all the time? If so, this could be the root of the problem, because with every reconfiguration is potentially expensive. I didn't met this yet but I do not use AVFoundation capture often so I'll need to look at it.

Martin

[ygreq]

Thank you, Martin!

It does happen every time. What would you suggest to change in order to stop this from happening?

[ygreq]

I just changed the fps to 29.97 to see how it reacts and this happened.

[lavd]  Error while decoding frame (rc == -1094995529): Invalid data found when processing input.
[video dec.] Detected internal codec: UYVY
[video dec.] Successfully reconfigured display to 640x480 @30.00p, codec UYVY
[lavd] Using decoder: h264
[h264 @ 00000000564708c0] non-existing PPS 0 referenced
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] non-existing PPS 0 referenced
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] non-existing PPS 0 referenced
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] non-existing PPS 0 referenced
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] no frame!
[lavd]  Error while decoding frame (rc == -1094995529): Invalid data found when processing input.
[video dec.] New incoming video format detected: 640x480 @29.97p, codec H.264
[lavd] Using decoder: h264
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] no frame!
[lavd]  Error while decoding frame (rc == -1094995529): Invalid data found when processing input.
[video dec.] Detected internal codec: UYVY
[video dec.] Successfully reconfigured display to 640x480 @29.97p, codec UYVY
[lavd] Using decoder: h264
[video dec.] New incoming video format detected: 640x480 @30.00p, codec H.264
[lavd] Using decoder: h264
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] decode_slice_header error
[h264 @ 00000000564708c0] no frame!

[MartinPulec]

Hi, I've made a small change that may help in your case. Whenever the fps option is specified by user, it will be used in metadata instead of (potentially fluctuating) value returned by AVFoundation. The change is present in today's (2021-09-08) continuous mac build.