Video & audio not in sync problem

[leonardCN]

Im using Macbook Pro（M1 Max） BMD Web Presenter HD and TelevisionStudio HD
Web Presenter HD is connecting with macbook pro with usb type-c line.
and im having a not in sync problem after i started streaming
i have three log file which might include the problem and [2023-04-27 11-07-06] this one might be more valueable FYI? (to save your time just incase)
pls help! and i can give more details about this problem if it's needed.

 

[AaronD]

Is it a constant offset?
If so, there's a Sync Delay in the Advanced Audio Properties, and another delay in the Filters for each video source. Play with those until you get it right. A good way to do that quickly, is to record some, load that recording into your favorite video editor, separate the audio and video tracks in there, and see what it takes to line them up. Then translate it back to a setting in OBS and make another test recording...

---

Is it increasing? Good to start and then useless later?
That's a known problem with the Monitor, which is the only way to get audio out of OBS that isn't tied up in a stream or recording. The reason it does that is because the Monitor locks itself to the device that it's connected to, while the rest of OBS uses a different clock. Instead of resampling, it just grows the buffer, ad infinitum.

There are a couple of ways to fix that:

• Connect the Monitor to a different audio device that gets its clock from the same place that OBS does. This can be hard to tell, so it's effectively random.
• Insert a virtual device between the Monitor and anything physical. The idea here is that the virtual device gets its clock from the same place that OBS does, and so it solves this problem, and then the virtual device has its own chance to resample between itself and the physical one.
• Keep the connection as it is, and disrupt the flow of audio to the Monitor, just to reset the buffer. This could be:
  • Removing and re-adding the source, though this is way too drastic for frequent use.
  • Changing the Monitoring setting in Advanced Audio Properties to Monitor Off, and back again.
  • Muting/unmuting the source in the Audio Mixer dock, or in a script or other automation.

For that last point, it may help to have two different copies of each audio source: one goes to the Output only, and the other goes to the Monitor only. Then you can "blink" the Monitor copy without affecting the stream or recording.

 

[leonardCN]

Is it a constant offset?
If so, there's a Sync Delay in the Advanced Audio Properties, and another delay in the Filters for each video source. Play with those until you get it right. A good way to do that quickly, is to record some, load that recording into your favorite video editor, separate the audio and video tracks in there, and see what it takes to line them up. Then translate it back to a setting in OBS and make another test recording...

---

Is it increasing? Good to start and then useless later?
That's a known problem with the Monitor, which is the only way to get audio out of OBS that isn't tied up in a stream or recording. The reason it does that is because the Monitor locks itself to the device that it's connected to, while the rest of OBS uses a different clock. Instead of resampling, it just grows the buffer, ad infinitum.

There are a couple of ways to fix that:

• Connect the Monitor to a different audio device that gets its clock from the same place that OBS does. This can be hard to tell, so it's effectively random.
• Insert a virtual device between the Monitor and anything physical. The idea here is that the virtual device gets its clock from the same place that OBS does, and so it solves this problem, and then the virtual device has its own chance to resample between itself and the physical one.
• Keep the connection as it is, and disrupt the flow of audio to the Monitor, just to reset the buffer. This could be:
  • Removing and re-adding the source, though this is way too drastic for frequent use.
  • Changing the Monitoring setting in Advanced Audio Properties to Monitor Off, and back again.
  • Muting/unmuting the source in the Audio Mixer dock, or in a script or other automation.

For that last point, it may help to have two different copies of each audio source: one goes to the Output only, and the other goes to the Monitor only. Then you can "blink" the Monitor copy without affecting the stream or recording.

Thanks for your messages! I’m not a native English speaker so this gonna takes me some time to understand. But could you explain more about the Monitor you just mentioned? Does it refer to the preview and the PGM window?

 

[leonardCN]

Is it a constant offset?
If so, there's a Sync Delay in the Advanced Audio Properties, and another delay in the Filters for each video source. Play with those until you get it right. A good way to do that quickly, is to record some, load that recording into your favorite video editor, separate the audio and video tracks in there, and see what it takes to line them up. Then translate it back to a setting in OBS and make another test recording...

---

Is it increasing? Good to start and then useless later?
That's a known problem with the Monitor, which is the only way to get audio out of OBS that isn't tied up in a stream or recording. The reason it does that is because the Monitor locks itself to the device that it's connected to, while the rest of OBS uses a different clock. Instead of resampling, it just grows the buffer, ad infinitum.

There are a couple of ways to fix that:

• Connect the Monitor to a different audio device that gets its clock from the same place that OBS does. This can be hard to tell, so it's effectively random.
• Insert a virtual device between the Monitor and anything physical. The idea here is that the virtual device gets its clock from the same place that OBS does, and so it solves this problem, and then the virtual device has its own chance to resample between itself and the physical one.
• Keep the connection as it is, and disrupt the flow of audio to the Monitor, just to reset the buffer. This could be:
  • Removing and re-adding the source, though this is way too drastic for frequent use.
  • Changing the Monitoring setting in Advanced Audio Properties to Monitor Off, and back again.
  • Muting/unmuting the source in the Audio Mixer dock, or in a script or other automation.

For that last point, it may help to have two different copies of each audio source: one goes to the Output only, and the other goes to the Monitor only. Then you can "blink" the Monitor copy without affecting the stream or recording.

And I wonder if it’s the second situation, does it occurs because of my physical devices(BMD)?

 

[AaronD]

Thanks for your messages! I’m not a native English speaker so this gonna takes me some time to understand. But could you explain more about the Monitor you just mentioned? Does it refer to the preview and the PGM window?

And I wonder if it’s the second situation, does it occurs because of my physical devices(BMD)?

It's not a visual monitor. The term in this case comes from the pro audio world. A "monitor" there, is a speaker on stage that is aimed at the performer(s), or a set of speakers in a studio while the main output goes to a recorder or radio transmitter.

OBS is following the studio convention here. Nothing whatsoever to do with a visual display.
(although it's entirely possible to connect OBS's audio Monitor to an HDMI output, but that's still only the sound)

 

[leonardCN]

It's not a visual monitor. The term in this case comes from the pro audio world. A "monitor" there, is a speaker on stage that is aimed at the performer(s), or a set of speakers in a studio while the main output goes to a recorder or radio transmitter.

OBS is following the studio convention here. Nothing whatsoever to do with a visual display.
(although it's entirely possible to connect OBS's audio Monitor to an HDMI output, but that's still only the sound)

So in my situation, the monitor means… ‘apple air pods’ right? Cuz I’m monitoring the output audio with it as streaming.
(Thanks again for your reply!!).
And if so, can I use a headphone with 3.5mm audio line connect to BMD TelevisionStudio HD(the switcher that I was using) to monitor the output, to solve the problem?

 

[AaronD]

So in my situation, the monitor means… ‘apple air pods’ right? Cuz I’m monitoring the output audio with it as streaming.

Yep!

And if so, can I use a headphone with 3.5mm audio line connect to BMD TelevisionStudio HD(the switcher that I was using) to monitor the output, to solve the problem?

Maybe. Maybe not. Like I said, finding an audio output device that uses the same clock as OBS is effectively random. Try it and see if it works.

 

[leonardCN]

Yep!


Maybe. Maybe not. Like I said, finding an audio output device that uses the same clock as OBS is effectively random. Try it and see if it works.

Okay !! I think I get it now.

 

[leonardCN]

Yep!


Maybe. Maybe not. Like I said, finding an audio output device that uses the same clock as OBS is effectively random. Try it and see if it works.

Thank you AaronD
Thanks for sharing your knowledge in this forum!! I appreciate it!!

I don’t think I will facing the same problem again but may I get a more efficient way to communicate with you?(just in case)

 

[AaronD]

If it's on-topic for this forum, then keep it public on the forum so that others can benefit too. If it's off-topic for this thread, make a new one, again keeping it public so that others can benefit.

If it's related but technically off-topic for this forum, then you can click my name and Start Conversation. That's just between us, so it's generally discouraged for things that are on-topic and someone else is likely to have a problem with too.

 

[leonardCN]

If it's on-topic for this forum, then keep it public on the forum so that others can benefit too. If it's off-topic for this thread, make a new one, again keeping it public so that others can benefit.

If it's related but technically off-topic for this forum, then you can click my name and Start Conversation. That's just between us, so it's generally discouraged for things that are on-topic and someone else is likely to have a problem with too.

i see !
i'll come back here to ask for further help if the problem doesn't solved~
thanks a lot!!

 

[leonardCN]

here is the log. and im streaming right now again.
could you pls help me to check out if there's any buffering problem hapenning again?

 

[leonardCN]

If it's on-topic for this forum, then keep it public on the forum so that others can benefit too. If it's off-topic for this thread, make a new one, again keeping it public so that others can benefit.

If it's related but technically off-topic for this forum, then you can click my name and Start Conversation. That's just between us, so it's generally discouraged for things that are on-topic and someone else is likely to have a problem with too.

Hi AaronD im here continuing posting the log

 

[leonardCN]

Is it a constant offset?
If so, there's a Sync Delay in the Advanced Audio Properties, and another delay in the Filters for each video source. Play with those until you get it right. A good way to do that quickly, is to record some, load that recording into your favorite video editor, separate the audio and video tracks in there, and see what it takes to line them up. Then translate it back to a setting in OBS and make another test recording...

---

Is it increasing? Good to start and then useless later?
That's a known problem with the Monitor, which is the only way to get audio out of OBS that isn't tied up in a stream or recording. The reason it does that is because the Monitor locks itself to the device that it's connected to, while the rest of OBS uses a different clock. Instead of resampling, it just grows the buffer, ad infinitum.

There are a couple of ways to fix that:

• Connect the Monitor to a different audio device that gets its clock from the same place that OBS does. This can be hard to tell, so it's effectively random.
• Insert a virtual device between the Monitor and anything physical. The idea here is that the virtual device gets its clock from the same place that OBS does, and so it solves this problem, and then the virtual device has its own chance to resample between itself and the physical one.
• Keep the connection as it is, and disrupt the flow of audio to the Monitor, just to reset the buffer. This could be:
  • Removing and re-adding the source, though this is way too drastic for frequent use.
  • Changing the Monitoring setting in Advanced Audio Properties to Monitor Off, and back again.
  • Muting/unmuting the source in the Audio Mixer dock, or in a script or other automation.

For that last point, it may help to have two different copies of each audio source: one goes to the Output only, and the other goes to the Monitor only. Then you can "blink" the Monitor copy without affecting the stream or recording.

and here is the set up

 

[AaronD]

here is the log. and im streaming right now again.
could you pls help me to check out if there's any buffering problem hapenning again?

I don't see anything wrong with that log. It says the buffer is 42 milliseconds, but no expansion after that. 42ms is about 47 feet or 14.5 meters in air. If you're okay with speakers being that far away from you, then you're also okay with that buffer size.

That said though, I don't see the normal closing messages, so it's possible that the buffer grew a lot after the log ends.

Is it increasing? Good to start and then useless later?
That's a known problem with the Monitor, which is the only way to get audio out of OBS that isn't tied up in a stream or recording. The reason it does that is because the Monitor locks itself to the device that it's connected to, while the rest of OBS uses a different clock. Instead of resampling, it just grows the buffer, ad infinitum.

There are a couple of ways to fix that:

• Connect the Monitor to a different audio device that gets its clock from the same place that OBS does. This can be hard to tell, so it's effectively random.
• Insert a virtual device between the Monitor and anything physical. The idea here is that the virtual device gets its clock from the same place that OBS does, and so it solves this problem, and then the virtual device has its own chance to resample between itself and the physical one.
• Keep the connection as it is, and disrupt the flow of audio to the Monitor, just to reset the buffer. This could be:
  • Removing and re-adding the source, though this is way too drastic for frequent use.
  • Changing the Monitoring setting in Advanced Audio Properties to Monitor Off, and back again.
  • Muting/unmuting the source in the Audio Mixer dock, or in a script or other automation.

For that last point, it may help to have two different copies of each audio source: one goes to the Output only, and the other goes to the Monitor only. Then you can "blink" the Monitor copy without affecting the stream or recording.

If you're using the Monitor to feed your headphones directly, then this would still apply.

 

[leonardCN]

I don't see anything wrong with that log. It says the buffer is 42 milliseconds, but no expansion after that. 42ms is about 47 feet or 14.5 meters in air. If you're okay with speakers being that far away from you, then you're also okay with that buffer size.

That said though, I don't see the normal closing messages, so it's possible that the buffer grew a lot after the log ends.


If you're using the Monitor to feed your headphones directly, then this would still apply.

now i ended the streaming, could you please help me to check it again?

 

[AaronD]

now i ended the streaming, could you please help me to check it again?

Still 42ms, with no further increase. Did it sound okay?

22:11:08.724: adding 42 milliseconds of audio buffering, total audio buffering is now 42 milliseconds (source: 麦克风/Aux)

 

[leonardCN]

Still 42ms, with no further increase. Did it sound okay?

yes!! it sounded perfectly!!

 

[leonardCN]

Still 42ms, with no further increase. Did it sound okay?

it seems that your suggestion solved the problem.
i appreciated that so much !!!

 

[leonardCN]

Hi AaronD, im having the same problem again, everything is fine until a audio noise suddenly appears and disappears, after that the dis-match problem appears again..... and i got the log file uploaded....!