Audio Issues When Rendering

[Paul33]

I have shot a series of 4K clips with my smart phone and used an external lapel mic. All of the clips look great and sound great but when I render the project in VS2020 on a "same as first clip" basis, the audio is sounding wrong.

If I extract just one clip and render that on a "same as first clip" basis then the audio is fine but if I apply exactly the same settings to the entire project, then it reverts to being poor quality.

You can hear a short MP3 clip (quiet shot of a flower meadow in a gentle breeze) here >>>>> https://www.peterboroughimages.co.uk/audio.mp3 <<<<< where you can hear both choppy audio and that horrible "distorted underwater echo" effect ..... that is not on the original clip and its that I need to put right.

The MEDIAINFO audio data for the original clip with perfect audio is .......

ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 11 s 278 ms
Source duration : 11 s 328 ms
Bit rate mode : Constant
Bit rate : 64.0 kb/s
Channel(s) : 1 channel
Channel layout : C
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 87.4 KiB (0%)
Source stream size : 87.5 KiB (0%)
Title : Core Media Audio
Encoded date : UTC 2020-05-12 08:27:58
Tagged date : UTC 2020-05-12 08:28:09

The same data for the rendered project with the poor audio is ......

ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 13 min 28 s
Bit rate mode : Constant
Bit rate : 64.0 kb/s
Channel(s) : 1 channel
Channel layout : C
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 6.25 MiB (0%)
Language : English
Encoded date : UTC 2020-05-12 19:45:56
Tagged date : UTC 2020-05-12 19:45:56

The VS2020 rendering properties based on "same as first clip" are ......

NTSC non-drop frame (30 fps)
MPEG-4 Files
24 bits, 3840 x 2160, 25.001 fps
Frame-based
H.264 High Profile Video: 75933 Kbps
48000 Hz, 16 Bit, Mono
MPEG AAC Audio: 64 Kbps

Can anybody put me right here ?

[Ken Berry]

A couple of observations or questions. First, why are you rendering to NTSC standard? You don't provide the Properties of the video part of your project, just the audio, though that is understandable given your main question.

However, looking at the audio properties, you may have a problem in this regard. First, it seems that your smartphone is filming with a very variable frame rate. The one sample you show has a frame rate of 46.875 fps which is nowhere near any of the international standard frame rates. The closest would be 50 fps which is of course PAL. Hence my original question about why you are rendering to NTSC.

The standard NTSC frame rates are 30 or 60 (or more accurately 29.97 and 59.54 fps). And if VS is using the render Properties you give at the end of your question, then it will be inventing frames from the existing 46.875 fps video to get it up to 60 fps (or conversely throwing some away to get it down to 25.1 fps). And inventing frames by repeating existing frames, or throwing frames away, is obviously going to affect the audio and not just the video...

The reality is that Video Studio just doesn't like variable frame rates. It was designed to deal with and produce video with internationally standard frame rates. When people are having trouble with variable frame rates, we usually recommend they first convert the original video using a video converter program such as the freeware Handbrake. But given the sort of frame rate you cite, I am a bit confused as to what output format you should set Handbrake or other converter program to use. Setting it to use PAL 50 fps would seem to be the most sensible as it is the closest to 46.875 and so involve inventing a significantly lesser number of frames per second. Indeed, your output Properties show a frame rate of 25.1 fps which is extremely close to PAL's standard 25 fps -- another reason to go for PAL.

However, you obviously chose NTSC setting for a reason, and I assume you live in an NTSC area, so may want or need to output using NTSC settings...

The other aspect of your problem is that rendering one single clip from the project worked out well, but when everything is put together the rendering of the audio goes wonky. I can only assume this is because the variable frame rate issue becomes far more obvious with a number of clips. Variable frames can vary according to the action or lack of action in an individual clip. Flowers is a meadow may only require a low frame rate, while something with more action in would raise the frame rate. Applying a single frame rate across all this, and one based on the frame rate of the first clip in the project, is again a recipe for very wonky rendering.

But I can only repeat that you should try converting all your clips in Handbrake to a standard mp4. Then try them in your project again. Mind you, I suspect that is going to give you variable audio. So once the converted video is in the timeline, you may have to mute it and substitute the original audio (extracted beforehand from the original clips) in the audio tracks.

[Paul33]

Thanks Ken ..... will try putting these files through Handbrake.

I'm in the UK - PAL country - and I haven't chaosen NTSC. I selected "same as first video clip" and whenever I have done that, going back many months, it always comes up with that NTSC "drop frame" line and I have no idea why nor what it means but I'm certainly not choosing NTSC at any stage ..... that's what VS2020 is showing as "first clip" properties.

The full MEDIAINFO properties for the original file are ..........

General
Complete name : S:\Videos\Deene (20).mov
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt 0000.00 (qt )
File size : 103 MiB
Duration : 11 s 318 ms
Overall bit rate : 76.0 Mb/s
Encoded date : UTC 2020-05-12 08:27:58
Tagged date : UTC 2020-05-12 08:28:09
Writing library : Apple QuickTime
com.apple.quicktime.location.ISO6709 : +52.5165-000.5896/
com.apple.quicktime.publisher : ISO: 33.125
com.apple.quicktime.software : Created with FiLMiC Pro6.10.910065

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L5.1
Format settings : CABAC / 1 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 1 frame
Format settings, GOP : M=1, N=15
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 11 s 318 ms
Bit rate : 75.9 Mb/s
Width : 3 840 pixels
Clean aperture width : 3 840 pixels
Height : 2 160 pixels
Clean aperture height : 2 160 pixels
Display aspect ratio : 16:9
Clean aperture display aspect ratio : 16:9
Frame rate mode : Variable
Frame rate : 25.000 FPS
Minimum frame rate : 25.000 FPS
Maximum frame rate : 25.532 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.366
Stream size : 102 MiB (100%)
Title : Core Media Video
Encoded date : UTC 2020-05-12 08:27:58
Tagged date : UTC 2020-05-12 08:28:09
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 11 s 278 ms
Source duration : 11 s 328 ms
Bit rate mode : Constant
Bit rate : 64.0 kb/s
Channel(s) : 1 channel
Channel layout : C
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 87.4 KiB (0%)
Source stream size : 87.5 KiB (0%)
Title : Core Media Audio
Encoded date : UTC 2020-05-12 08:27:58
Tagged date : UTC 2020-05-12 08:28:09

[Paul33]

Spent three hours pushing all 49 4K video clips through handbrake to change the 25fps VFR to 25fps CFR and rebuilt the project with the handbrake outputs and ...... made absolutely no difference !

I can take any single clip and render it absolutely perfectly but if I then apply those properties to the entire project then the audio once again is a mess as per the sample above.

Very depressing !!!

PS: I have shot many dozens of projects previously, some with VFR and some with VFR that has been converted to CFR and never have I had an issue SOLELY with audio like this one. No sync issues and the voice audio is absolutely fine but the background sound is all over the place !

[lata]

Hi Paul
Some have complained about quality when rendering whilst Smart Proxy is being used for the video clips, If you are using SP try disabling that option, some users commented that they also had to delete the proxy files.
Also from Share have you tried deselecting Smart Render, that has also been known to fix unusual audio issues whilst rendering

As Video Studio seems to be reading the video properties wrong, or different to MediaInfo I would suggest avoiding the Same as First Clip and choose another MPEG 4 template similar to your original files properties.

I notice that Quicktime is being used, do you have the Quicktime codec installed, just the Codec not the player, you never know?

[Paul33]

Thanks Trevor - more things to try there !!!

[Paul33]

Just to wrap this one up, tried every suggestion but still a series of nonsensical outputs from VS2020 so far as the audio was concerned.

In desperation, I downloaded a trial copy of Adobe Premiere Pro and it nailed it first time without any issues ..... in fact it even removed the clicks that were also dogging the audio in VS2020.

I have no explanation for this one but, for the time being at least, I'm going to be switching to Premiere Pro.

[tletter]

in fact it even removed the clicks that were also dogging the audio in VS2020.

VS has been adding audio blips to rendered files since at least X9 (see https://forum.corel.com/search.php?st=0 ... only&ch=-1). By now it's obvious that Corel isn't interested in fixing such a basic flaw.

tletter
https://www.youtube.com/user/tletter

[Paul33]

Thanks to all the experts on here. Without you, VS would be a complete non-starter as the official Support team are beyond shocking and lack any expertise based on the dozen or so tickets I have raised. You folk keep the head of VS above water and Corel owe you big time !