Hello,

I've been pounding my head with this issue and cannot find an appropriate resolution.

I have a file (called filename.alac) which contains the raw ALAC stream, specifically the mdat payload. (Equivalent to the output from ` mp4box -raw filename.m4a` where filename.m4a contains an alac stream)

I am trying to mux this raw stream into an m4a (M4A /mp42/isom) container. Is this possible with MP4Box? 

I have tried the following command:
`mp4box -add filename.alac#audio filename_new.m4a`

But I received the following output:
```
[Importer] Cannot load filter for input file "filename.alac"
Failure while importing import: Requested URL is not valid or cannot be found
Error importing filename.alac#audio: Requested URL is not valid or cannot be found
```


Muxing Raw ALAC Stream into M4A
This is a GitHub Issue
repo:gpac
owner:gpac
Title : Muxing Raw ALAC Stream into M4A
Issue date:

--- start body ---
Hello,

I've been pounding my head with this issue and cannot find an appropriate resolution.

I have a file (called filename.alac) which contains the raw ALAC stream, specifically the mdat payload. (Equivalent to the output from ` mp4box -raw filename.m4a` where filename.m4a contains an alac stream)

I am trying to mux this raw stream into an m4a (M4A /mp42/isom) container. Is this possible with MP4Box? 

I have tried the following command:
`mp4box -add filename.alac#audio filename_new.m4a`

But I received the following output:
```
[Importer] Cannot load filter for input file "filename.alac"
Failure while importing import: Requested URL is not valid or cannot be found
Error importing filename.alac#audio: Requested URL is not valid or cannot be found
```


--- end body ---
