Re "Issues with Large Files" and "Recent Radio Downloads Not Playing".

[RS]

>From: Budge Sent: Tuesday, January 24, 2017 10:38

>Have you looked at your files with AtomicParsley to see if you get the 
>message I get "MPEG-4 Unknown profile" on your problem files?  It would be 
>good to learn if we have the same problem.  This is no longer a long file 
>problem.

Thanks for drawing attention to AtomicParsley.  I was aware of it because 
get_iplayer uses it, but I have never tried running it, and I didn't know 
how powerful it was.

Have you looked at the stsz tables to confirm what Linn said about them?

I have not seen the Unknown profile message.

I have not yet tried splitting a file into different length test files.  I 
have been using a file of over 2 hours.  I did create a DASHhigh download 
with the --raw option.  I was suprised that it created a file with a .m4a 
extension, because I thought that was a container.  Anyway mp4creator would 
not accept the .m4a extension for an input file.  I had to rename the file 
with a .aac extension.  I then got a large number of messages that a large 
number of bytes (about 400,000 each time) was being discarded.  I ended up 
with a file not even VLC could play about 1% of the original size.

I then tried to multiplex the raw file with ffmpeg.  I was surprised to see
major_brand: iso6
minor_version: 0
compatible_brands: iso6dash
When I tried to explore the raw file with AtomicParsely I got
AtomicParsley error: unsupported MPEG-4 file brand found 'iso6'

I am using the versions of ffmpeg (v3.0) and AtomicParsley (v0.9.6) bundled 
with v2.95 of get_iplayer and the Windows installer.

I have never seen ISO6 as a Major Brand before.  I gather it is a 2012 
revision of the MPEG4 standard.
https://en.wikipedia.org/wiki/ISO_base_media_file_format
It seems as recently as May 2013 VLC was unable to play ISO6 files.
https://sourceforge.net/p/gpac/discussion/287547/thread/5979f3d7/

Maybe the problem has something to do with that.