05-04-2017, 10:04 AM
I have been testing video input lag for Super Smash Bros. Melee for quite some time now, but until recently I never took any tests of the audio lag. I have searched the forums on post findings, however the few older threads I found were on very old Dolphin versions and didn't say much about how they tested the lag. They were also focused on audio-video sync, so perhaps the setups used just had more video input lag than the ones I used, so that the offset of audio was decreased.
I think that for emulation validity, it's important that there is no additional input lag over console, both for video and for audio. Because of this, I didn't want to just test audio sync by measuring audio against video, but to test audio and video input lag by comparing both of them to the button input signal, all connected to a 4-channel oscilloscope.
My testing results are here: http://kadano.net/SSBM/inputlag/audio.html
To give a short tl;dr: On console, the average video input lag is 67 ms on average and the average audio input lag is 36 ms. I took 80 samples to calculate these averages, so they should be fairly accurate.
On Dolphin 5.0 with Direct3D11 and the XAudio2 backend (0 buffer), the average video input lag is 48 ms on average and the average audio input lag is 162 ms.
The 162 ms I got on a PC with an Asus Xonar DG sound card in direct mode with all sound effects disabled. Noteworthy is that the integrated Via audio of a different PC was considerably faster.
On the Via audio PC, I've only tested the Ishiiruka Dolphin build configured for Melee netplay ("FM4.9") yet. The fastest averages I got there for the audio input lag were 103 ms. Note that for many of the emulation series, I only took 10 samples when I noticed that audio lag was >90 ms, since I consider that amount far too much for serious play, so I don't think there is merit in finding out whether it's 10 ms more or less for a certain configuration.
The purpose of this thread is raising awareness about the audio lag problem, finding out more about this audio lag, what it's caused by and how to decrease it. I do not rule out the possibility that this amount of audio lag is not present on all Dolphin setups, however I ask that people who claim so provide details about their setup so I can replicate it and test the audio lag for it.
I think that for emulation validity, it's important that there is no additional input lag over console, both for video and for audio. Because of this, I didn't want to just test audio sync by measuring audio against video, but to test audio and video input lag by comparing both of them to the button input signal, all connected to a 4-channel oscilloscope.
My testing results are here: http://kadano.net/SSBM/inputlag/audio.html
To give a short tl;dr: On console, the average video input lag is 67 ms on average and the average audio input lag is 36 ms. I took 80 samples to calculate these averages, so they should be fairly accurate.
On Dolphin 5.0 with Direct3D11 and the XAudio2 backend (0 buffer), the average video input lag is 48 ms on average and the average audio input lag is 162 ms.
The 162 ms I got on a PC with an Asus Xonar DG sound card in direct mode with all sound effects disabled. Noteworthy is that the integrated Via audio of a different PC was considerably faster.
On the Via audio PC, I've only tested the Ishiiruka Dolphin build configured for Melee netplay ("FM4.9") yet. The fastest averages I got there for the audio input lag were 103 ms. Note that for many of the emulation series, I only took 10 samples when I noticed that audio lag was >90 ms, since I consider that amount far too much for serious play, so I don't think there is merit in finding out whether it's 10 ms more or less for a certain configuration.
The purpose of this thread is raising awareness about the audio lag problem, finding out more about this audio lag, what it's caused by and how to decrease it. I do not rule out the possibility that this amount of audio lag is not present on all Dolphin setups, however I ask that people who claim so provide details about their setup so I can replicate it and test the audio lag for it.