Audio popping issues when using Vbox HD2 recordings

[Danny@APT]

I've been using RaceRender for some time now without any problems using footage from GoPro's and an older Video Vbox, but since we upgraded to a Vbox HD2 I've encountered annoying audio popping during playback when editing that remains in the final rendered footage.

At first I suspected it was an issue with the placement of the mic, but after some testing I noticed that the audio problems only occur within the RaceRender software itself, and any files created with it- playback of the original files through Windows 10 and other video players are crystal-clear. Even if I edit and render the footage elsewhere, as soon as I play it through your software the popping occurs?

This footage highlights the audio problems- https://www.youtube.com/watch?v=5ekjK_rohXw

Has anyone else had this issue with Vbox HD2 recordings? As far as I'm aware I'm running the latest release and Windows 10 is fully up to date?


Thanks

[Weston@HPTuners]

You might try changing the audio sample rate if encountering audio popping or other distortions... Most likely, you're outputting at 48 kHz when the input audio is 41 kHz, or vice versa. With .MP4 output, only the 44100 Hz and 48000 Hz rates will actually be selectable, but changing it from one to the other could produce different audio quality.

[Danny@APT]

You might try changing the audio sample rate if encountering audio popping or other distortions... Most likely, you're outputting at 48 kHz when the input audio is 41 kHz, or vice versa. With .MP4 output, only the 44100 Hz and 48000 Hz rates will actually be selectable, but changing it from one to the other could produce different audio quality.

I understand what you're saying, but the issue appears when playing the original raw MP4 footage through RaceRender. The audio issues do not present themselves when playing the original file in any other video editing software or during normal playback in Windows.

I've just installed the latest RaceRender release, plus Racelogic's firmware update for the HD2, to see if the problem had gone away, but it's still there.

I've tried altering the workspace settings to match the 48kHz sample rate of the original recording, as well as outputting the edited file at 48kHz too, but the popping persists throughout.

If it helps, I can upload a short Vbox HD2 recording to Dropbox so you can see the problem for yourselves?

[Danny@APT]

Here's the short recording- https://www.dropbox.com/s/hlto5ehem2..._0001.mp4?dl=0

[Weston@HPTuners]

These types of intermittent audio pops tend to be a result of a small timing issue when accessing the input audio samples. Video players and traditional editors can work a bit differently and aren't as sensitive to timing issues, but as a multi-input video processor, we process the audio in chunks for precise periods of time, and that's what seems to be bringing the issue to the surface here.

The usual workaround for this would be to re-encode the video file, with the expectation that the output audio would then have different or more precise timing data that will work without issue. That could be done with a traditional video editor, or a re-encoding tool like Handbrake.

If you could upload the original raw video to Dropbox, I can take a look and see if there's anything better we could do on our end to help with this, but it would be premature to make any promises...

[Danny@APT]

These types of intermittent audio pops tend to be a result of a small timing issue when accessing the input audio samples. Video players and traditional editors can work a bit differently and aren't as sensitive to timing issues, but as a multi-input video processor, we process the audio in chunks for precise periods of time, and that's what seems to be bringing the issue to the surface here.

The usual workaround for this would be to re-encode the video file, with the expectation that the output audio would then have different or more precise timing data that will work without issue. That could be done with a traditional video editor, or a re-encoding tool like Handbrake.

If you could upload the original raw video to Dropbox, I can take a look and see if there's anything better we could do on our end to help with this, but it would be premature to make any promises...

Thanks for your input, I'll try processing the raw footage through another editor first and see how it plays in RaceRender.

The Dropbox link in post #4 is an original piece of raw footage directly from the Vbox HD2 (set to record when above a set roadspeed). If you would like a longer clip, I'm sure I can find something more suitable.

Thanks again for your help.

[Weston@HPTuners]

Ok, I'll take a closer look... I had heard some popping in the audio when I played in Dropbox's online player, and had assumed that was the end result after processing it through RaceRender.

There doesn't seem to be any popping when played in Windows 10's default video player, but it shows up in Windows Media Player, and then has even more when brought into RaceRender. The diagnostics log shows some timing errors when trying to get the audio samples, so that's indicative of the situation I described earlier. I'll do some experimentation with this and see if we can coax it into giving us what we need...

[Weston@HPTuners]

Update... I spent a couple hours on this and attempted several workarounds, but unfortunately the Microsoft Media Foundation decoders are ultimately having the problem with this video. It seems that they're not giving us the complete decoded audio samples, and there are incorrect audio sample durations being reported for this file as well. The two may be related and could both indicate timing problems, but either way the core decoding problem is unfortunately beyond what we're able to control from within our software.

Being that some popping is also evident in Windows Media Player and the Dropbox online player, that would typically point to how this video was encoded, rather than it being just a decoding issue. Some video players and editors are less affected by these things than others, but it's hard to say which ones would or would not reliably work in this case. I did try to run it through Handbrake, and that appears to fix the audio issue for both RaceRender and Windows Media Player, but that tool did have some other issue that made it miss the first 7-8 seconds of video frames here. Both audio and video appeared to be ok after that.

[Danny@APT]

Thanks for taking the time to attempt a workaround. I'll speak to Racelogic and see if they can correct the problem at their end.

For the time being, I've tried rendering the footage through other software first before using it in RaceRender and it does seem to correct the audio issues I've had with the Vbox HD2 recordings. So until Racelogic fix the problem, that's how I'll have to work.

Thanks once again for trying, and hopefully Racelogic will be as helpful.

Cheers!