Blackmagic Forum

Hello community,

i want to report a bug!

Exporting MP4 with 320Kb/s AAC Audio is actually 192Kb/s on Windows machines.

In the name of the company I am working for, I can say we were all quite happy when you finally added that higher audio quality for Windows, but now we feel fooled. The quality is just not sufficient enough.

Is there a fix to get the real 320Kb/s?

Thank you!

Michael

If you use Windows 10, that's still impossible

Which version of Resolve?
Is the data rate you read per channel or per track?

Thank you for your answer! We use the plugin Voukoder with DR18.6 and 320Kb/s (and more) is working with that on Windows 10. So I think it is a BM problem. I am just wondering why I am able to choose that setting.

Still confused.
R u saying it’s not working with the plugin, or is working?
And I still don’t know channel or track measurement.

I am sorry for the confusion!

Okay, exporting a MP4 file in DR18.6 with 320Kb/s AAC is not possible, even the 320Kb/s option is available. I can set it to 320 in the audio menu and even export it, but it will only export audio with 192Kb/s.

In order to check if DR 18.6 is able to export 320Kb/s audio on a Windows machine in general, I tested the Voukoder Plugin with DR: It works. It shoes 320Kb/s in the properties of my Media Player Classic and Windows file explorer.

In the DR 18.6 Export page in the audio delivery dialog it says 320Kb/s for Track Data Rate (see picture attached).

We, Windows 10 users, have all the same issue.

I also have this problem except it's 256Kb/s when I export out 320Kb/s.

To get 320, you need Windows 11.

I'm using Windows 11.

Well that's weird.

I also use Win 11. 320 Kb AAC are not possible - only 256.

This seems to be a Windows restriction. Resolve apparently does not have its own audio AAC encoder. Since this has been the case for a long time, Black Magic does not seem to want to include its own AAC encoder.

Obviously a Windows restriction. If you desperately need 320, get a Mac. Works fine here.
I admit that BM shouldn't offer it under Windows.

Uli Plank wrote:Obviously a Windows restriction. If you desperately need 320, get a Mac. Works fine here.

Not really helpful.

Same here: 320kb/s yields 256kb/s on Windows 11.

I wrote "if you desperately need it". Otherwise you have to wait until either side is fixing it, MS or BM.

Uli Plank wrote:I wrote "if you desperately need it".

Still...that's like suggesting we self-amputate our own legs to get Section 8 housing because we're a little short for rent this month.

Patience is a virtue

The workaround we found is to export H.264 in a Quicktime container with a PCM audio track. Then, launching a script with ffmpeg to rewrap in MP4 and encode to AAC 320 kbit/s. That's very fast since the video stream stay untouched.

For those who are scripting-scared, Shutter Encoder can do it, there's even a watch folder capability.

anyone know how to solve this issue???

Hi faiqasaif,

Sorry for nobody replying to your question, I'm on a Mac now so cannot test this myself but I'm wondering if anybody else out there can test this for faiqasaif?

Export a video with AAC audio at 320Kb/s and check in MediaInfo if it's actually 320 or 192. Might be different in Resolve 20.

faiqasaif wrote:anyone know how to solve this issue???

Resolve most likely uses Windows own AAC encoder and even if Resolve's setting says 320kb/s, Windows own limit is eg. 192kb/s, so this is why you ar not getting expected result. Can't find specifically max value for Win11 AAC encoder, but there is an info saying 192kb/s is max. for Windows.

I think this been discussed already many times.

As others have said, I think the best workaround is just to use uncompressed PCM Linear audio instead. It's not going to take up that much room in an MP4 file, and will still work with YouTube, Vimeo, and all the other social media services (which will re-encode all uploads anyway to their own internal formats).

Marc Wielage wrote:use uncompressed PCM Linear audio instead.

Would that Resolve allowed that for MP4.

Marc Wielage wrote:As others have said, I think the best workaround is just to use uncompressed PCM Linear audio instead. It's not going to take up that much room in an MP4 file, and will still work with YouTube, Vimeo, and all the other social media services (which will re-encode all uploads anyway to their own internal formats).

No need. 192kb/s for stereo delivery gives very good quality. Well better than old MP3 at 128kb/s which was used so much.
You couldn't store PCM in mp4, but recently spec has been adjusted (ISO/IEC 23003-5:2020) and this is now officially supported.