Audio/Video Out of Sync

[Jim web]

A new puzzle springs out at me as I try to negotiate the current
'segmentation' problems.

I decided to try the hvfhd1 mode and chose some of the sections of the
Wilson / Gershwin Prom check this out.

The 'Rhapsody in Blue' snippet file the BBC offer is fine. 50fps 1280x720
with a 125k stereo soundtrack. Plays fine with VLC (my usual player).

I also started fetching the full Prom, but ctrl-C'd it after a while as I
just wanted to check using the first few mins. This also plays fine.

However the 'American in Paris' snippet file I fetched gives no sound at
all from VLC! The video looks fine, but its a silent film! 8-)

ffmprobe says it is the same as the Rhapsody. And if  drop it onto
Audacious *that* can play the audio in the mp4 without any problems. But
VLC is silent.

So Audacious can play the audio from all the above. ffmprobe can show me
the details which seem the same. But two play with audio as usual with VLC
whilst the other stays silent.

I used

 --modes=hvfhd1 --no-tag pid <>

for each. (I also tried omitting the no-tag.)

Anyone explain? These files are a bit big to keep trying during the
daytime! Although the fetching seems pretty fast, they'd eat up my quota if
I had to keep re-fetching. So a more targetted approach to diagnosing this
would be good. Is the file weird, or is VLC the problem, or... ?

Jim

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