Convert mpg to dvr-ms

[kayleigh]

I found this article about installing & configuring an MPEG-2 decoder in VMC. It involves changing some registry settings, but if you really want to improve the WAF, you may find it's worth it.
http://mediacenterexpert.blogspot.com/20...fault.html

*SNIP*
Here's a decoder utility that might make things easier for you...
http://mediacenterexpert.blogspot.com/20...ility.html

[djones]

Thank you. Yeah, I have used this util before when I was playing with the cyberlink decoder (trying to get smooth playback on GBPVR) and it works very well. Unfortunately, that isn't the main problem with VMC - only dvr-ms and wmv filetypes are viewable in the 'recorded tv' section of VMC so changing the decoder won't resolve the issue.

Rubbish M$ and Vista! Why can't they produce software that we want rather than trying to convert us to the way they want us to work?

[djones]

You can get good quality and compression with WMV but it's all pretty variable. The transcode time can also be fairly long depending on the settings you use.

<SNIP>

Cheers,
Brian

I've just tried the higher of the two pre-defined WMV conversion settings:

Code:

<Conversion name="WMV-1200kb/s" cmd="-y -i {SOURCE_FILE} -vcodec wmv2 -b 1200k {DEST_FILE}" targetExtension=".wmv" />

However, when played full screen, the picture is very blocky (filesize roughly 1/4 of the original). The docs for ffmpeg detail using a couple of options that I thought might help. Has anyone used any of these options or higher bitrates or have any opinions? Filesize isn't really an issue.

To have a constant quality (but a variable bitrate), use the option '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst quality).

When converting video files, you can use the '-sameq' option which uses the same quality factor in the encoder as in the decoder. It allows almost lossless encoding.

Thanks.

[bgowland]

However, when played full screen, the picture is very blocky (filesize roughly 1/4 of the original). The docs for ffmpeg detail using a couple of options that I thought might help. Has anyone used any of these options or higher bitrates or have any opinions? Filesize isn't really an issue.

There might be some useful suggestions WRT ffmpeg if you search the forums. I seem to remember some threads discussing fine-tuning (advanced options etc.).

I have to admit I don't use ffmpeg with GB-PVR for transcoding anything and didn't realise the results with the 1200Kb/s WMV option were so bad full-screen (just tried a couple of tests - nasty blocky/jerky).

Higher bitrates aren't necessarily the answer - I get good results with 823Kb/s with wmv3 using a 2-pass transcoder process but it's horribly slow and not compatible with GB-PVR.

I notice the pre-defined settings use wmv2 (Windows Media Video v8) - if you can get it to work with wmv3 (Windows Media Video v9) you might get better results. I couldn't get it to work in tests though.


Cheers,
Brian

[djones]

Unfortunately, it appears that ffmpeg only supports decoding and not encoding of wmv3.

[sub]

Correct.

[bgowland]

djones - do you have Windows Media Encoder v9 installed? If not, go to the MS downloads page and install it.

I just found this...

http://www.microsoft.com/windows/windows...aspx#link3

Although it says the wmcmd.vbs file comes with the WME9 SDK, I've found a copy in the main WME9 install directory (no need to install SDK). There are about a million command-line parameters (OK - small exaggeration ) but mpg files are supported as the source. Worth a look?

Cheers,
Brian

[djones]

Definiately. Thanks for this, I hadn't thought of trying that route!

[bgowland]

Definiately. Thanks for this, I hadn't thought of trying that route!

Yeah - I've had WME9 and the SDK installed on my machine for a long while but rarely have need for them (or think about them) - it was actually a google search which picked up on that page.

One thing you might want to look at is using a WME9 profile file (PRX). According to the command-line help, you can specify a profile to provide the AV parameters you want. Nice and easy to create PRX files with the WME GUI.

Cheers,
Brian

[bgowland]

Thinking about this....

I've just been playing with the wmcmd.vbs script and it takes forever to transcode stuff. If WAF is important then the time taken to get good quality might not help things.

You could always just get a DVB-T capture card, set the BDA Multiplexer option to DVR-MS, set auto-convert to ASAP to convert dvr-ms files to mpeg2, make sure the option for deleting the original file is turned off.

Hey presto - you have a dvr-ms source and an mpeg2 copy.

Cheers,
Brian