Problem re-encoding captured digital TV
 

Hi all,

My apologies if this is not an appropriate newsgroup for my query. I'd really
appreciate it if someone could help me solve the problem.

I have a Vstream digital tuner card and recorded for 60 minutes which resulted
in a 3GB MPEG file.

I tried converting it to an AVI with pocket divx encoder, virtual dub, and
TMPGENC, but all failed to convert a single byte with different error messages -
TMPGEnc claimed it was an unsupported file, yet I can play it back with Windows
Media Player on my system.

Ulead VideoStudio was able to convert the file to an ~8MB avi with no
compression and I then tried to re-encode with pocket divx encoder but pocket
divx encoder claimed there was a serious problem with the frame synchronisation
(I think).

What could be the cause of these problems?

--
Ben Thomas - Melbourne, Australia
Opinions, conclusions, and other information in this message that do not
relate to the official business of my employer shall be understood as neither
given nor endorsed by it.

Problem re-encoding captured digital TV
 

Ben Thomas wrote:
Hi all,

My apologies if this is not an appropriate newsgroup for my query.
I'd really appreciate it if someone could help me solve the problem.

I have a Vstream digital tuner card and recorded for 60 minutes which
resulted in a 3GB MPEG file.

I tried converting it to an AVI with pocket divx encoder, virtual
dub, and TMPGENC, but all failed to convert a single byte with
different error messages - TMPGEnc claimed it was an unsupported
file, yet I can play it back with Windows Media Player on my system.

Ulead VideoStudio was able to convert the file to an ~8MB avi with no
compression and I then tried to re-encode with pocket divx encoder
but pocket divx encoder claimed there was a serious problem with the
frame synchronisation (I think).

What could be the cause of these problems?

Blimey!!

What package produced the original 3gb file? Although that huge size
suggests that it is uncompressed, there will have been some codec or other
used to produce the file. I think the answer depends on understanding
which one. I'm very surprised that virtual dub baulked at it though. I
wonder if it is the sheer size at fault. Can you post more details of your
capture software please? Ultimately you may need to find something else to
capture from your card. Virtual Dub could do that, even.




---
avast! Antivirus: Outbound message clean.
Virus Database (VPS): 0542-3, 19/10/2005
Tested on: 19/10/2005 22:37:57
avast! - copyright (c) 1988-2005 ALWIL Software.
http://www.avast.com

Problem re-encoding captured digital TV
 

Ben Thomas wrote:
Hi all,

My apologies if this is not an appropriate newsgroup for my query. I'd
really appreciate it if someone could help me solve the problem.

I have a Vstream digital tuner card and recorded for 60 minutes which
resulted in a 3GB MPEG file.

I tried converting it to an AVI with pocket divx encoder, virtual dub,
and TMPGENC, but all failed to convert a single byte with different
error messages - TMPGEnc claimed it was an unsupported file, yet I can
play it back with Windows Media Player on my system.

Ulead VideoStudio was able to convert the file to an ~8MB avi with no
compression and I then tried to re-encode with pocket divx encoder but
pocket divx encoder claimed there was a serious problem with the frame
synchronisation (I think).

What could be the cause of these problems?

I've got one of these cards. Are you sure you have the latest software?
Look on www.kworld.com.tw
The recorded video stream can be converted to dvd, but it takes hours to
run and produces a video with poor lip sync.
I used Ulead Video studio 7 to master the video file to DVD. It took
hours (about 4) to render a 1 hour program. I hav'nt bothered since and
my shuttle based PVR project is on hold pending better cards and software.
Dave

Problem re-encoding captured digital TV
 

Ian wrote:
Ben Thomas wrote:
Hi all,

My apologies if this is not an appropriate newsgroup for my query.
I'd really appreciate it if someone could help me solve the problem.

I have a Vstream digital tuner card and recorded for 60 minutes which
resulted in a 3GB MPEG file.

I tried converting it to an AVI with pocket divx encoder, virtual
dub, and TMPGENC, but all failed to convert a single byte with
different error messages - TMPGEnc claimed it was an unsupported
file, yet I can play it back with Windows Media Player on my system.

Ulead VideoStudio was able to convert the file to an ~8MB avi with no
compression and I then tried to re-encode with pocket divx encoder
but pocket divx encoder claimed there was a serious problem with the
frame synchronisation (I think).

What could be the cause of these problems?

Blimey!!

What package produced the original 3gb file? Although that huge size
suggests that it is uncompressed, there will have been some codec or
other used to produce the file. I think the answer depends on
understanding which one. I'm very surprised that virtual dub baulked
at it though. I wonder if it is the sheer size at fault. Can you
post more details of your capture software please? Ultimately you may
need to find something else to capture from your card. Virtual Dub
could do that, even.

A 3Gbyte file for a 60 minute programme corresponds to a bit rate of 7.1Mb/s
which is abit on the high side for a MPEG2 UK SD channel but not by a huge
amount. In my experience the BBC channels are typically 2 to 2.5 Gbyte /
hour.

What is probably happening is that the file is probably a transport stream
file which has the MPEG audio and video streams for the channel but may
contain some of the other transport packets as well.

This is also why the encoders are upset. They will be expecting a programme
stream with just pure mpeg data and not a transport stream with different
headers and other packets.

You can either use ProjectX or PVAStrumento to handle the transport stream
files and either produce programme stream files or separate out the video
and audio into separate video and audio files (mpv and mpa) . The latter can
then be edited and re-muxed as required again using freeware tools.

That's the approach I used to use, but because I do a lot of this I tried
out VideoRedo (www.videoredo.com), and I'm now a convert to using that.

It costs money ($50) but it has so many benefits that for me it was well
worth it.

It opens both mpegs and transport streams
It has a great user interface for fast editing.
It works directly at frame level rather then the GOP (Group of pictures)
that many editors use
It only re-encodes the small number of frames around edits so it is very
fast
It can pick out single channels even from a multi-channel transport stream
file. I've used that to simultaneously record and process programmes on
BBC1, BBC2 and BBC3 using one tuner.
It is very good at maintaining audio/video sync.
It seems to have very good support from the developers

I know that sounds a bit enthusiastic and I felt a bit dubious up until a
couple of months back when I tried the demo. Just a few days of use
convinced me not to go back to my former methods.

Problem re-encoding captured digital TV
 

Dave Spam wrote:

I've got one of these cards. Are you sure you have the latest
software? Look on www.kworld.com.tw
The recorded video stream can be converted to dvd, but it takes hours
to run and produces a video with poor lip sync.
I used Ulead Video studio 7 to master the video file to DVD. It took
hours (about 4) to render a 1 hour program. I hav'nt bothered since
and my shuttle based PVR project is on hold pending better cards and
software. Dave

Assuming the files are transport streams as I suggested in my other reply it
should be possible to edit and convert to DVD compatible material in minutes
rather than hours. I edit 2 hour transport streasm down to standard mpegs
with all ads removed etc. Processing time is typically about 7 minutes (3.5
minutes per hour of video). If you use programmes that decode internally,
edit and then re-encode then it will be very slow as you suggest, but you
don't need to do that if you are just doing simple cut edits rather than
adding effects. Not re-encoding also helps preserve quality.

Now if you want to convert to avi with divx or xvid encoding to get the file
size down, or to resolution convert for smaller displays then that will take
much longer, but, you do get the benefit of much smaller file sizes.

I routinely convert all my recordings to divx/avi at high quality and can
then fit about 8 hours (4 to 5 films) on a dvd.

I would say that on typical platforms you should be getting about 1x real
time encoding per pass of divx encoding at the native resolution. E.g 1 hour
takes 2 hours to process in a 2 pass encoding. If the frames are downsampled
first then you will get a significant speed up as the downsampling is much
faster than the encoding. So a downsample from 720x576 to 360x288 means only
a quarter of the data to re-encode and I see at least a doubling in speed.
E.g. 1 hour in less than 1 hour even with 2 pass.

Problem re-encoding captured digital TV
 

Bob Tidey wrote:
Dave Spam wrote:


I've got one of these cards. Are you sure you have the latest
software? Look on www.kworld.com.tw
The recorded video stream can be converted to dvd, but it takes hours
to run and produces a video with poor lip sync.
I used Ulead Video studio 7 to master the video file to DVD. It took
hours (about 4) to render a 1 hour program. I hav'nt bothered since
and my shuttle based PVR project is on hold pending better cards and
software. Dave

snip

I would say that on typical platforms you should be getting about 1x real
time encoding per pass of divx encoding at the native resolution. E.g 1 hour
takes 2 hours to process in a 2 pass encoding. If the frames are downsampled
first then you will get a significant speed up as the downsampling is much
faster than the encoding. So a downsample from 720x576 to 360x288 means only
a quarter of the data to re-encode and I see at least a doubling in speed.
E.g. 1 hour in less than 1 hour even with 2 pass.




I'll give that a go within the next few days and report back.
Thanks
Dave

Problem re-encoding captured digital TV
 

wrote:

As you already have TMPGEnc for a Freeware editor try Cuttermaran fin
place of VideoRedo.

Have both and think Cuttermaran the better.

Project X much better than PVAstrumento .

Links to both under Downloads Digital TV at http://www.doom9.org/

Malcolm

I agree ProjectX in general works more reliably than PVAStrumento. When I
used these I did occasionally find the odd capture that ProjectX would snarl
on that PVAStrumento would handle. So I had scripts that ran ProjectX as the
main method but if that 'timed out' would run PVAStrumento as a back up.

I then used to use Cuttermaran or Mpeg2Schnitt as the mpv/mpa editor before
then using ImagoMux as the final remux tool. I switched allegiance between
these a few times. I found Cuttermaran had some nice features, but
MPeg2Schnitt had some virtues too, particularly in its screen layout to make
editing quick.

For me though VideoRedo has eliminated the demux and remux stages and
allowed whole transport stream capture for multi-channel recording without
any fiddling around. Plus the vernier scroll and thumbnail timeline of
frames around the edit point make selecting edit points really slick.