HydrogenAudio

Lossy Audio Compression => Opus => Topic started by: tehabe on 2019-11-11 17:03:14

Title: Huge bitrate differences while using VBR
Post by: tehabe on 2019-11-11 17:03:14
I rip and converted my music collection with XLD and Opus set at 96 kbps and VBR, which was essentially the default. And the bitrates are all over the place, one album all songs have above 200 kbps and another barely over 100 kbps.

Also most of the albums I converted from FLAC with the same settings are not all over the place when it comes to the bitrate, this is very confusing.
Title: Re: Huge bitrate differences while using VBR
Post by: [JAZ] on 2019-11-11 19:05:55
Since you say that most of the files converted from your flac files have the expected bitrate, could it be that the "bloated" files are multichannel?  I believe the bitrate target is just for "stereo" content.
Title: Re: Huge bitrate differences while using VBR
Post by: tehabe on 2019-11-11 21:27:14
No, all files are stereo. The original source is the CD in all cases.

Edit: I found the answer, the artwork I added is being included when calculating the bitrate and I had huge files included. With the artwork the file had ~212 kbps w/o the artwork the went to 93.5 kbps. This behaviour is weird but now I know what is happening.
Title: Re: Huge bitrate differences while using VBR
Post by: MetaPixel on 2019-11-12 06:34:45
Out of curiosity, what software were you using to check the bitrate? Some of them seems to calculate the average bitrate dividing file size by the audio duration. It's not accurate and causes problems with embedded data, but works well enough most of the time.
Title: Re: Huge bitrate differences while using VBR
Post by: tehabe on 2019-11-12 08:02:46
I saw these with media-info on macOS and AIMP on Android.
Title: Re: Huge bitrate differences while using VBR
Post by: magicgoose on 2019-11-12 10:57:07
Quote
Opus set at 96 kbps and VBR, which was essentially the default. And the bitrates are all over the place, one album all songs have above 200 kbps and another barely over 100 kbps
There's nothing wrong with that, it's OK. Some things are easier to encode with that quality level.
Title: Re: Huge bitrate differences while using VBR
Post by: tehabe on 2019-11-12 13:59:47
There's nothing wrong with that, it's OK. Some things are easier to encode with that quality level.

Thankfully I found out what the reason for this was, the size of the album art.
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