Long h.264 files not playing on some computers

[VATv]

Greetings.

We have a client who is having issues viewing longer (25-40 minute) h.264/.mp4 files on both their Macs and PCs.  The video plays properly for about 4 minutes then stops playing completely or the audio stops.  My understanding is they are using QT Player and Sony Catalyst Browse.  They get the same issue when attempting to upload to Brightcove.  All files play correctly on our systems and upload properly to our YouTube channel.

Videos are encoded from the timeline in h.264, 1080, 12 Mbps, VBR 2-pass, AAC Audio @ 320 kbps

Any thoughts are appreciated.

Thank you!

Matt

[Warren Heaton]

Hmmm... I wish I had an extra $10 for every time I had files that played perfectly on my systems, but not on a client's.

I'd look at where the files are being stored.  Are they on the Macintosh HD or the C drive?  A USB thumb drive?  NAS storage?  SAN storage?

What happens if they play the video in a web browser from YouTube?

It would also be worth testing if they can play long MP4 files that originated from someplace else.