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mp4 & m4a music files getting dynamically compressed

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Archetype:
Hi JRiver crew.

I've been listening to surround files with JRiver 31 for the better part of this year and everything has been fine. Those files were either Wav, Aiff or flac. They all sound great. Recently I've been listening to some music that had been encoded as mp4 and the music gets heavily compressed (in real time) when there is a lot of dynamics. I've listened to the files at the finder folder level and they sound fine and don't do the dynamic grabbing.

As an experiment, I encoded the same files as MKV and the music doesn't do the compression thing. I'm hoping to find the culprit setting and not have to re-encode the music.

Is there a setting in MC that I'm missing? I've been listen to music and watching movies with JRiver for a while and have never had this issue. Any help in the right direction would be good.

Thanks alot,

Archetype

blgentry:
A few guesses and questions:  If DSP is turned off, MC shouldn't have any way of doing dynamics processing music files.  However, it may be doing some kind of conversion if you are sending the files to a DLNA playback device. 

What are you playing back to?  Is it attached via USB, network, etc ?

MKV is a container format.  It does not specify any CODEC.  An MKV could contain FLAC, PCM, DTS, MP3, or nearly any other format.  What format did you specify?

My best guess (and it's just a guess) is that you are using a DLNA renderer and it does not support AAC.  Something (MC or the renderer) is converting it to something else.  Perhaps a low bit rate MP3.  ...and you are hearing this sonic degradation caused by the conversion.

I could be totally wrong.

Brian.

Archetype:
Hi blgentry.

No DLNA. I just have MC audio device set playback through a MOTU audio interface (PCI Card...old skool :-).

Hmm, interesting. I didn't encode the mp4s. I used to encode to WAV or AIFF but switched to flac which has never giving me any issues. Is there anyway to know what is contained inside the mp4? I was wondering if the mp4 metadata is telling MC something that gets stripped off when I convert to MKV.

You mention not supported AAC. Might the mp4 actually contain AAC files for JRiver is converting the output??

Thanks,

A.

blgentry:
You can see the CODECs in your file by using MC's Tag Action Window.  Click on one of your files, then open the Tag window with Edit > Tag (or use alt-enter).

In the Tag window (on the left), you'll see lots of fields.  You want the "compression" field.  There's a search box at the bottom where you can type and narrow it down to the field you want (compression).  It should tell you what CODEC is used in the file.  See the screenshot for one of my files.

Brian.

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