Requests For Features

Jim web web at
Thu Jul 23 01:59:30 PDT 2015

In article <55AFBEF6.2030704 at>, Budgie
<ajebay at> wrote:
> Hi Jim, Thanks for the reply.  Yes I wondered if "passing through"
> ffmpeg would do the trick but was not sure of correct commands.  Will
> try on a copy. No time at present.  Book keeping!!! Alastair.

FWIW I tend to use this to 'snip' files

ffmpeg -ss "hh:mm:ss" -i infile.<ext> -acodec copy -vcodec copy -t
"hh:mm:ss" output.<ext>

The codec copy parts ensure the 'payload' is unchanged. (You can use the
simpler way to specify this as Vangelis has explained. I use the above
because there are times when I want to alter one codec or the other and
this approach reminds me of what's going on.)

The -ss and -t parts are optional for taking a section out of the input
file. If you leave them out it should just try to tidy up - and recontainer
if you've chosen a different output container format.

The -ss specifies a start point at a time in hours:mins:sec from the start
of the input file.

The -t specified a duration for the output file length, staring from the
-ss time.

Mention this in detail because yesterday I found a file I'd downloaded
using gip that has a 'glitch' at the start. 

If I play it normally with VLC the picture jumps and gives blocking
rectangles during the first sec and the time count showed by VLC jumps. If
I just let VLC play on the vision and sound are out of lip synch by a fair
amount. However if I jump forward or back at all, lip synch is restored.

Its the first time I've seen this for a gip fetched file. But I've seen
this in captures from DVB-T2. I've not done it yet, but I suspect that
simply using the above to trim the first second or two off the file will
remove the problem.

BTW The VLC option I wanted to suggest was as follows:

Try using

vlc --codec avcodec,all <filename>

when playing files.

If it can find the correct things that may help VLC to play files that its
default choices have timestamp or other problems with. Here it also helps
minimise problems with DVB-T2 captures where the audio codec *changes* on
the fly during transmission.

Note as I've said, though, this may depend on what versions/packages you
have installed.

BTW2 If you are using Linux I'd recommend you check out ROX filer. I tend
to write my own simple desktop ROX front ends for things like the above so
I can use them via drag-and-drop or a click. Not to everyone's taste, but I
much prefer it. Albeit that I run ROX filer *and* xfce in parallel. :-)


Armstrong Audio
Audio Misc

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