Issues with Large Files

[Budge]

On 13/01/17 00:24, RS wrote:
>> From: Budge Sent: Thursday, January 12, 2017 18:26
>
>> Many thanks.  Yes I agree ffmpeg was my first thought but I am spoiled
>> for choice of command options.  ffprobe output didn't tell me what I
>> was looking for although that may be due to me not understanding what
>> I was looking at.  However I have no doubt ffmpeg will clean things
>> up.  I shall try a few options and see what happens.
>
> Thanks for drawing attention to this.  I did hope something similar
> might lead to a solution of the problem I have playing DASH/M4A/AAC
> files on my AGPtEK A02.  I found about a year ago that ffmpeg created
> files with Major Brand M4A and Minor Version 512, which the AGPtEK
> player  did not seem to like.  I used
> mp4box  <file>.m4a -brand M4A:0 -out <file1>.m4a
> from https://gpac.wp.mines-telecom.fr/mp4box/mp4box-documentation/
> to change the Minor Version to 0.  I then found I could play the files,
> but only if they were shorter than 14min at 128kbit/s.
>
> Following your post I have looked at it again.  I see that by default
> mp4box -brand M4A introduces interleaving of 500ms.  I tried
> mp4box  <file>.m4a -brand M4A:0 -inter 1000 -out <file1>.m4a
> to give 1s interleaving and that allowed a 24min file to be played, but
> the display showed Format error after 15min.  I also tried -inter 2000
> for 2s interleaving.  That again allowed a 24min file to be played but
> with a Format error after 5min.
>
> mp4box <file> -info
> gives a bit more information than ffprobe and ffmpeg.  GPAC refers to
> segments, fragments and interleaving.  I am not sure how these relate to
> what Linn calls chunks.
>
> I have tried running ffmpeg with -acodec copy and with -acodec aac, but
> that does not seem to help.
>
> artisticforge said Handbrake fixed his files.  Handbrake will not
> convert audio only files.  I have seen a workaraound to add dummy video,
> but that seemed a bit cumbersome.  I'll have to give it a try.
>

Interesting.  I thought I would have a look at mp4box but cannot find it 
although I have gpac installed.  I could download and build but wonder 
why it is not shown in Packman repo along with gpac.  Will dig further.

Meanwhile I am learning (slowly) a whole lot more about this through 
necessity.  I should point out however that my files are from 2 hours 
and up to more than twice as long.  Strange that only the Linn kit 
chokes on these but they are now aware of the issue.