2 devices audio issue

michaelwu

michaelwu

New Member
Hi there,
Since version 29.0 , if I have 2 same video capture device (with same VID/PID), say dev1 and dev2, the dev1 audio always been
played even I choose video from dev2. If I add both dev1 and dev2 manually, instead get audio from both two device, I only get double
audio of dev1.. back to earlier version before version 29.0 everything is ok. Could anyone please tell me how to do? Or will this be fixed
in next version?
Thanks & Best Regards
Michael Wu
 
A

AaronD

Active Member
USB is supposed to have a unique serial number for each device, in addition to the VID/PID. It's a lot cheaper, however, for the factory to make them EXACTLY identical, which of course includes that serial number. Reputable manufacturers (not re-branded resellers), won't do this, but if yours did, then you apparently have the exact same single device appearing on two different ports.

Some operating systems can still differentiate them by the port that they're connected to, but again, USB is not supposed to rely on that.

Windows, as I've heard, is even more stupid and naive in its insistence that everyone did follow the official standard, in that it doesn't even use the device's descriptor the second and subsequent times. It just looks up the VID/PID in a table of cached drivers and loads that. If it's not there, THEN it reads the descriptors to see what to put in that entry of the table. That makes it difficult (for hobbyists at least) to create a new custom device to use on Windows, because the first attempt (which is practically guaranteed to fail somehow) gets cached forever and that's just what it is.

Linux is better about using whatever the device is *this time*, without remembering what it was before, but it's still a mixed bag whether a given kernel will make sense of multiple devices that are EXACTLY identical, and use them simultaneously and independently. I've had some that do and some that don't. The ones that don't will use one just fine, but the others might as well be unplugged in terms of accessing them.
 
michaelwu

michaelwu

New Member
Thanks, it's true for the serial number, they are same. Strange thing is the Vmix and Potplayer and some other applications I've tested are work ok without this issue, except OBS version 29.0 and later .
 
Suslik V

Suslik V

Active Member

Please post a log with your issue! Here's how...

OBS Studio creates a log file each time you run it which contains very useful diagnostic information. Without a log file, it's much harder for any support volunteers to figure out problems and your post may be ignored. To upload a log file, go to the Help menu > Log Files > Upload Last Log...
obsproject.com obsproject.com
 
Suslik V

Suslik V

Active Member
You have two audio devices:
Code: 
HDMI (ezcap Dual CamLink CH1)
HDMI (2- ezcap Dual CamLink CH2)

you can try to make checked "Use custom audio device" in the properties of each "Video Capture Device" of OBS and select one of the mentioned above audio devices as actual sources of the audio.
 
michaelwu

michaelwu

New Member
yes, it is exactly what I have done: At first, I didn't check the "Use custom audio device" , the audio come automatically from CH2 whether I choose video device CH1 or CH2. Then I checked the "Use custom audio device" and I choose audio CH1 for video CH1, and audio CH2 for video CH2, but still I only get the CH2 audio (double CH2 audio). And I tested OBS 27.0.* , and OBS 25.*.* they all work perfect. Just version 29.0 and later with problems.
 
michaelwu

michaelwu

New Member
Suslik V said:
Can you add log after this action completed?
Click to expand...
Actually, the log I posted yesterday is already this action, but I can do it again tomorrow if you like. And if you want me to do some other actions before log please let me know, Thanks
 
Suslik V

Suslik V

Active Member
The log from the v27 too. It will be useful for comparison for developers (with both "Use custom audio device" checked and external device selected, and not checked). It will be very hard to prove that OBS needs fix :)

If issue is 100% reproducible: feel free to fill the issue form on github - https://github.com/obsproject/obs-studio/issues

Rollback to version that works OK for you, because you may wait for months for the fix and next release...
 
michaelwu

michaelwu

New Member
Suslik V said:
The log from the v27 too. It will be useful for comparison for developers (with both "Use custom audio device" checked and external device selected, and not checked). It will be very hard to prove that OBS needs fix :)

If issue is 100% reproducible: feel free to fill the issue form on github - https://github.com/obsproject/obs-studio/issues

Rollback to version that works OK for you, because you may wait for months for the fix and next release...
Click to expand...
Thanks a lot, the log I just checked, it is v29.1.3, are we watched the same link?
1687825832869.png
 
Suslik V

Suslik V

Active Member
I mean you need to add logs from the OBS version where all was working OK (not only from OBS where you get this issue). Obviously, developers don't have two same devices you have, thus they will look at OBS logs to compare what changed between OBS releases and why OBS no longer work for you as it did before.
 
Suslik V

Suslik V

Active Member
Let's speed up troubleshooting (by determining which last version of OBS don't have issue):
  1. You need to download OBS v29.1.1 and v28.1.2 to your PC, you can find all versions here: https://github.com/obsproject/obs-studio/releases
  2. Make a new folder for each OBS and make them portable as described here (follow the steps after the "If it was not clear" words): https://obsproject.com/forum/thread...»-when-opening-app-settings.82157/post-346499
  3. Run OBS v28.1.2 (portable) and add Video Capture Device sources to the scene (make them both work as you usually do)
  4. Make sure that the sound issue is present (or not) - Remember result (remember time and date)!
  5. Exit OBS
  6. Run OBS v28.1.2 (portable) again and for each Video Capture Device source make "Use custom audio device" option checked, and select HDMI (ezcap Dual CamLink CH1) or HDMI (2- ezcap Dual CamLink CH2) device as source for the audio (as you usually do)
  7. Make sure that the sound issue is present (or not) - Remember result (remember time and date)!
  8. Exit OBS
  9. Run OBS v28.1.2 (portable) again and click main menu Help > Log Files > Show Log Files. File explorer window should open and you'll see OBS log files from the last sessions.
  10. Copy log files you remembered in p4 and p7 (look for them by time and date)
  11. Repeat p3 to p9 but use OBS v29.1.1 (portable) instead of OBS v28.1.2
Now you have 4 log files (v28.1.2 with option checked/unchecked, and v29.1.1 with option checked/unchecked) and 4 results (issue either present or not).
Share your results and log files.

I have choose for the tests the v28.1.2 because you said since v29.0 you have issues.
I have choose for the tests v29.1.1 because there were some changes in the code of OBS.

So, what the results?
 
michaelwu

michaelwu

New Member
Suslik V said:
Let's speed up troubleshooting (by determining which last version of OBS don't have issue):
  1. You need to download OBS v29.1.1 and v28.1.2 to your PC, you can find all versions here: https://github.com/obsproject/obs-studio/releases
  2. Make a new folder for each OBS and make them portable as described here (follow the steps after the "If it was not clear" words): https://obsproject.com/forum/threads/crash-with-«could-not-find-locale-ini-path»-when-opening-app-settings.82157/post-346499
  3. Run OBS v28.1.2 (portable) and add Video Capture Device sources to the scene (make them both work as you usually do)
  4. Make sure that the sound issue is present (or not) - Remember result (remember time and date)!
  5. Exit OBS
  6. Run OBS v28.1.2 (portable) again and for each Video Capture Device source make "Use custom audio device" option checked, and select HDMI (ezcap Dual CamLink CH1) or HDMI (2- ezcap Dual CamLink CH2) device as source for the audio (as you usually do)
  7. Make sure that the sound issue is present (or not) - Remember result (remember time and date)!
  8. Exit OBS
  9. Run OBS v28.1.2 (portable) again and click main menu Help > Log Files > Show Log Files. File explorer window should open and you'll see OBS log files from the last sessions.
  10. Copy log files you remembered in p4 and p7 (look for them by time and date)
  11. Repeat p3 to p9 but use OBS v29.1.1 (portable) instead of OBS v28.1.2
Now you have 4 log files (v28.1.2 with option checked/unchecked, and v29.1.1 with option checked/unchecked) and 4 results (issue either present or not).
Share your results and log files.

I have choose for the tests the v28.1.2 because you said since v29.0 you have issues.
I have choose for the tests v29.1.1 because there were some changes in the code of OBS.

So, what the results?
Click to expand...
thanks for the detailed instructions, here the results:
29.1.1 uncheck (only audio from CH1 can get): https://obsproject.com/logs/5wI41plOjIvBRO1e
29.1.1 checked (only audio from CH1 can get): https://obsproject.com/logs/OTRJjSaST4JIdo9u
28.1.2 uncheck (no audio can be heard) : https://obsproject.com/logs/ljXoJKEWZGWMuM0B
28.1.2 checked (both 2 audio can be heard, works well) :https://obsproject.com/logs/eVCEg5AVGcUz3Oec
 
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