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rdp / screen-capture-recorder-to-video-windows-free

a free open source windows "screen capture" device and recorder (also allows VLC/ffmpeg and others to capture/stream desktop/audio)
https://github.com/rdp/screen-capture-recorder-to-video-windows-free/releases
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Video and audio are out of sync #33

Closed andrasfuchs closed 10 years ago

andrasfuchs commented 10 years ago

I used SCR v0.9.6 on two different computers.

The capture worked just fine on one of them, but on the other the audio is always getting out of sync when we do a recording.

What can be the cause for this?

rdp commented 10 years ago

It gets more out of sync over time?

On Fri, Dec 20, 2013 at 8:37 AM, Andras Fuchs notifications@github.comwrote:

I used SCR v0.9.6 on two different computers.

The capture worked just fine on one of them, but on the other the audio is always getting out of sync when we do a recording.

What can be the cause for this?

— Reply to this email directly or view it on GitHubhttps://github.com/rdp/screen-capture-recorder-to-video-windows-free/issues/33 .

andrasfuchs commented 10 years ago

Yes, in the sample video I tested it does. It start with a 2.5-second-long delay of the video compared to the audio and then increases to 4.5-5 seconds until the end of the 6 minutes long video.

andrasfuchs commented 10 years ago

I have made some new tests and compared the SCR logs from the console window.

The main differences are that the file with out-of-sync audio has a 650 kb/s video rate, the other one with proper audio has 2440 kb/s.

The first's color-space is yuv420p, the second's is yuv444p, but I'm not sure it matters.

And finally and probably most importantly: the first had many frames dropped during the recording.

The framerates of the MP4 files (checked in MPC-HC, with the Shift+F10 command) are 5.874fps and 28.758fps, but the target was 30fps for both.

rdp commented 10 years ago

What is your registry value: HKEY_CURRENT_USER\Software\virtual_audio_capture (note to self: maybe mine combined audio with video so it drops audio packets as well?)

On Mon, Dec 23, 2013 at 5:23 AM, Andras Fuchs notifications@github.comwrote:

I have made some new tests and compared the SCR logs from the console window.

The main differences are that the file with out-of-sync audio has a 650 kb/s video rate, the other one with proper audio has 2440 kb/s.

The first's color-space is yuv420p, the second's is yuv444p, but I'm not sure it matters.

And finally and probably most importantly: the first had many frames dropped during the recording.

Interestingly though the framerate of the MP4 files (checked in MPC-HC, with the Shift+F10 command) are exactly 30fps independently from the number of dropped frames. I remember that a few weeks ago I did some tests and they always had slightly lower fps values indicating that some frames are missing. Is this normal?

— Reply to this email directly or view it on GitHubhttps://github.com/rdp/screen-capture-recorder-to-video-windows-free/issues/33#issuecomment-31116459 .

andrasfuchs commented 10 years ago

It is "total reads 412576 total discontinuity blips 2, total overflows 0" on the computer where I didn't have the problem.

I can't check the other computer now.

I have changed the recording mode to HWND on the computer we had problems, and now it works fine since then.

It just takes a lot of time to set the HWND to the right value every time when we do a recording :/

rdp commented 10 years ago

OK audio out of sync may be improved with latest version...

On Mon, Dec 30, 2013 at 11:17 AM, Andras Fuchs notifications@github.comwrote:

It is "total reads 412576 total discontinuity blips 2, total overflows 0" on the computer where I didn't have the problem.

I can't check the other computer now.

I have changed the recording mode to HWND on the computer we had problems, and now it works fine since then.

It just takes a lot of time to set the HWND to the right value every time when we do a recording :/

Reply to this email directly or view it on GitHubhttps://github.com/rdp/screen-capture-recorder-to-video-windows-free/issues/33#issuecomment-31359505 .

andrasfuchs commented 10 years ago

We had no problems so far if the video was above 15 fps or so.