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snipping ts files neatly



 
 
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  #31  
Old December 21st 14, 11:37 AM posted to uk.tech.digital-tv,uk.comp.os.linux
Andy Furniss[_3_]
external usenet poster
 
Posts: 130
Default snipping ts files neatly

Jim Lesurf wrote:
In article , Jim Lesurf
wrote:
I'm also wondering if it may be 'good practice' to use avconv or
ffmpeg first to create a new version 'tidied up' via the above
route before then snipping it.


This turns out to be a bad idea here at present. The main reason
being that when I play such a 'cleaned' version with VLC the
indicators for elapsed time and duration simply show zeros. Hence
making it impossible to use VLC to find 'snip' times for splitting
the file!

I've also now encountered one file which both avconv and ffmpeg can't
fully process because of a duff section in the middle. I can use -ss
-t to avoid that section and they then work. But I can't 'clean' the
entire file in one go. I guess the problem is due to a burst of
interference that corrupted the data during recording.

What is curious is that even with 'copy' for the codec options both
programs fall over when they encounter a long enough 'corrupt'
section. Is there another option to "plug on regardless"? I'll see if
I can find one.


Not sure about "plug on", though I have seen ffmpeg devs recommend not
using ffmpeg to cap live ts for that reason.
  #32  
Old December 21st 14, 12:01 PM posted to uk.tech.digital-tv,uk.comp.os.linux
Tony Houghton[_3_]
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Posts: 6
Default snipping ts files neatly

In ,
Jim Lesurf wrote:

In article , Jim Lesurf
wrote:
I'm also wondering if it may be 'good practice' to use avconv or ffmpeg
first to create a new version 'tidied up' via the above route before
then snipping it.


This turns out to be a bad idea here at present. The main reason being that
when I play such a 'cleaned' version with VLC the indicators for elapsed
time and duration simply show zeros. Hence making it impossible to use VLC
to find 'snip' times for splitting the file!


It's normal for the timestamps to be meaningless in a recorded ts file,
I've never known sensible times to be displayed in one. Your first step
should be to remux into a container format more suitable for a file.
  #33  
Old December 21st 14, 12:31 PM posted to uk.tech.digital-tv,uk.comp.os.linux
Dave Farrance
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Posts: 1,551
Default snipping ts files neatly

Jim Lesurf wrote:

I'm also wondering if it may be 'good practice' to use avconv or ffmpeg
first to create a new version 'tidied up' via the above route before then
snipping it. Comments?


I'll mention here what I know about avconv vs ffmpeg, from my use of
them. I understand that avconv forked from ffmpeg because ffmpeg's main
developer was not considered to be "responsive" enough in dealing with
some problems that had been identified, and for a while, avconv was better
than ffmpeg. However, the consensus now is that avconv development is
long stalled and ffmpeg is forging ahead with a major new revision that is
considerd to be the "king" of mpeg4 encoders.

ffmpeg is not yet in Debian/Ubuntu and derivative distros, and where they
do have an "ffmpeg" package, it's a front-end to avconv. (Ubuntu has
committed to restoring the "real" ffmpeg in parallel with avconv in its
next release). Very good pre-compiled static builds of 32 and 64 bit
ffmpeg-2.5 are available via ffmpeg.org and seems to work fine on all
Linux x86 distros (make sure that you select the static build and not a
distro-specific build for an old distro).

My own experience is that avconv is noticeably deficient in comparison to
the real ffmpeg, with it producing broken and sometimes unplayable output
when I simply want to splice video and audio together, and its encoded
output has unsatisfactory compression artifacts. The real ffmpeg seems to
produce an output that looks perfect and plays fine on the Raspberry-Pi
media players (Raspbmc and omxplayer) which is the main selling-point for
me.
  #34  
Old December 21st 14, 12:49 PM posted to uk.tech.digital-tv,uk.comp.os.linux
Andy Furniss[_3_]
external usenet poster
 
Posts: 130
Default snipping ts files neatly

Tony Houghton wrote:
In , Jim Lesurf
wrote:

In article , Jim Lesurf
wrote:
I'm also wondering if it may be 'good practice' to use avconv or
ffmpeg first to create a new version 'tidied up' via the above
route before then snipping it.


This turns out to be a bad idea here at present. The main reason
being that when I play such a 'cleaned' version with VLC the
indicators for elapsed time and duration simply show zeros. Hence
making it impossible to use VLC to find 'snip' times for splitting
the file!


It's normal for the timestamps to be meaningless in a recorded ts
file, I've never known sensible times to be displayed in one. Your
first step should be to remux into a container format more suitable
for a file.


Ideally yes, but Jim wants the sound untouched, which for UK DVB HD can
be tricky.

I think ffmpeg will put latm into mkv but the result may need (a player
that uses) ffmpeg to correctly play it. Didn't his TV already fail this
test.

HD also has sound that flips between 2 and 5.1 channels, which further
complicates things for putting into a container which has a header
describing the stream. Again I think mkv made and played by ffmpeg may
pass the test, but many containers won't.
  #35  
Old December 21st 14, 01:52 PM posted to uk.tech.digital-tv,uk.comp.os.linux
Jim Lesurf[_2_]
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Posts: 4,141
Default snipping ts files neatly

In article , Tony Houghton
wrote:
In , Jim Lesurf
wrote:


In article , Jim Lesurf
wrote:
I'm also wondering if it may be 'good practice' to use avconv or
ffmpeg first to create a new version 'tidied up' via the above route
before then snipping it.


This turns out to be a bad idea here at present. The main reason being
that when I play such a 'cleaned' version with VLC the indicators for
elapsed time and duration simply show zeros. Hence making it
impossible to use VLC to find 'snip' times for splitting the file!


It's normal for the timestamps to be meaningless in a recorded ts file,
I've never known sensible times to be displayed in one. Your first step
should be to remux into a container format more suitable for a file.


What do you suggest? This is all for ts streams I've recorded from
'Freeview' BBC1/2/4.

When I tried changing to some other formats a few days ago they either lost
the audio (when played on the TV) or lowered the quality. So I'd need a
container for which I can use -acodec copy -vcodec copy and will play. I
listed the formats the TV handbook claims it can play a while ago (can
repeat that if wished). But it also warns that it may not play all files if
they aren't exactly as the TV makers expected. i.e. the usual catch-all
excuse of device makers. :-)

Jim


Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

  #36  
Old December 21st 14, 01:59 PM posted to uk.tech.digital-tv,uk.comp.os.linux
Jim Lesurf[_2_]
external usenet poster
 
Posts: 4,141
Default snipping ts files neatly

In article , Andy
Furniss [email protected] wrote:

I think ffmpeg will put latm into mkv but the result may need (a player
that uses) ffmpeg to correctly play it. Didn't his TV already fail this
test.


Yes. But its possible I was doing something else wrong at the time. So I
can check again later on. And I can't off-hand recall if I made the
'changed contained' versions with the distro avconv or with the
ffmpeg below...

FWIW the version of ffmpeg I've built in a user directory says it is

N-65311-g6f3e15a

and the date I built it was Aug 6 2014

config --enable-gpl

is it worth getting a newer version for my purposes? And to clarify,
what are the best config options, etc, for ensuring maximum usefulness?

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

  #37  
Old January 5th 15, 02:00 PM posted to uk.tech.digital-tv,uk.comp.os.linux
Jim Lesurf[_2_]
external usenet poster
 
Posts: 4,141
Default AVchopper and ClassicRip: was snipping ts files neatly

Posting to say that I've now made a version of my simple 'chopper' for AV
files on my software page at

http://www.audiomisc.co.uk/software/index.html

I've called it "AVchopper". It essentially just acts as a front end for
either ffmpeg or avconv. You give it an 'edit list' of times and it
generates a series of output files that contain the same content as the
chosen source AV file, but starting and finishing at the specified times.
It uses the 'copy' options for the codecs to preserve the content. More
info in a Help file included. The 'C' source is also included for those who
enjoy a laugh at daft coding. :-)

FWIW I also added a linux version of my 'ClassicRip' program. This uses
cdparanoia to rip Audio CDs, etc, in a way that may be particularly useful
for 'classical' music fans who want one work-per-file for musical works
that have movements as successive tracks on a CD. Again there's a Help file
and the source code.

The above are written as ROX apps, but should work with other desktops and
terminals, etc.

For the ts files I've recorded from HDTV I find that running them through
ffmpeg or avconv actually makes them work with fewer problems when played.
Seems to 'tidy them up' in terms of the container even though the AV
payload is the same.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

 




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