[Wylug-help] Analysing and transcoding MPEG transport streams

[Dave Fisher]

Hi,

I've spent many fruitless days, googling (plus reading manpages, howtos
and mailing lists) in an effort to learn how to convert MPEG transport
stream files (recorded from DVB capture cards) into program stream
formats that can be reliably played via an average player (or
re-recorded as dvd-video).

Having exausted myself, and my capacity to think up new search
strategies, I'm posting this help request in the hope that someone else
on the list has had better luck.

My immediate need is to convert files recorded by Kaffeine, but I'd much
rather learn how to analyse and convert MPEG streams/files in a generic
way.

For example, Kaffeine claims to offer recording in TS, MPEG_PES and
MPEG_PS formats, but whatever option I choose seems to result in *.mt2
files which the file utility identifies as "MPEG transport stream data".
Googling suggests this interpretation is correct, i.e. Kaffeine doesn't
actually output *program* streams at all (encapsulated or otherwise).

Avidemux appears to offer a know-nothing method of demuxing then
remuxing these *.m2t files, but I suspect that it is broken (e.g. audio
and video are out of synch when you use the default setting to merely
copy - rather than transcode - the original streams into an MPEG program
stream container). Moreover, even if it did work, such black-box are are
rarely much use in the full range of real world cases. Projectx (a java
app, yuck) claims better performance than avidemux, but it's GUI is
nothing like the documentation and its CLI options appear to be ignored
by the binary I've tried.

I realise that there are better tools than file, but I am struggling to
find any video or dvb diagnostic utilities that are sufficiently
well-documented to know a) how to use them and b) how to decifer their
output.  Most appear to be designed for post-processing in a pipe, so
their output is not easily read by humans, and mostly unreadable.

A tiny minority of the tools I've looked at are copiously documented,
but quantity != quality.

From what I can gather, there are any number of encoding/decoding
applications that can convert the files for me (mplayer/mecoder and
transcode spring to mind), but they require appropriate input options.
Merely relying on the availability of sensible default format detection,
doesn't appear to be an option in most cases I've tried.

It's practically impossible to set the correct input options without
knowing more about the *.m2t files which Kaffeine produces. Moreover,
even when I know an input file's format, the filtering and output
options for tools like transcode are less than transparent (I realise
that this is, in part, because tools like transcode rely on long chains
of client utilities to do much of their work for them).

While I'd appreciate a simple recipe to convert Kaffeine's *.m2t files
into something like a VOB formatted program stream, I'm really hoping
that someone can help me get a bit further than that.

Still, any positive suggestions will be gratefully recieved.

Dave