Reducing file size / bitrate

[marcelr]

Encoding to SVCD using the maximum CBR. Quality is very good (480*480) but I'd like to fit more on one disk. I burn the mpg2 file as VCD swithing off the vcd compliancy.

I understand I should switch to VBR. What settings should I use for VBR in Tmpgenc ?

Any other recommendations on how to reduce filesize without sacraficing audio/video ?
Thank you.

[SaSi]

You can use single pass or 2 pass VBR in Tmpgenc. For SVCD, recommend 2000kbps average with 2600 max and 200 min.

Also, a large part of the space is occupied by the audio at 224kbps. For SVCD quality I have found that Tmpgenc's Layer II encoder at 64kbps joint stereo is quite good. This reduces the audio size to 1/6th almost compared to 224kbps. Also, doing VBR at 2000kbps gives you 30% more space compared to CBR. Add all that up and you get almost 40~45% more space.

Another approach is to try the venerable Kwag's tweaking to the SVCD endoding. He claims 2 hours on a SVCD, perhaps too much but if you are looking for more content, it's worth having a try. Go to www.kvcd.net

[Coop]

Marcel,

Bit rate (among other things) determines your file size and quality. The lower your bitrate the smaller your file, and the lower it's quality will be. VBR lets you specify average, maximum, and minimum settings.

[ZippyP.]

Any other recommendations on how to reduce filesize without sacraficing audio/video ?

VBR can, if used wisely, reduce filesize without reducing quality. It uses bits more efficiently by applying a higher bitrate to high action scenes which need it, and saving bits from low action scenes. So, the average bitrate (and filesize) when compared to CBR is lower while maintaining quality.

How low you will go on average bitrate depends on personal choice. Sasi's choice of 2000 will give great results, I will sometimes go as low as 1800.

Of course, 2-pass VBR can take twice as long to encode.

[marcelr]

Sasi,

and others, thank you for the reply. One more question though.
I have not seen the Tmpgenc's Layer II encoder at 64kbps joit stereo in the tmpgenc application. Could you let me know where to look ? When I click 'Setting' (next to the 'Load' button) and choose the Audio tab in version 2.58.44.152 it is not there. I am probably not looking in the right place. Thank you.

[marcelr]

Sasi,

and others, thank you for the reply. One more question though.
I have not seen the Tmpgenc's Layer II encoder at 64kbps joit stereo in the tmpgenc application. Could you let me know where to look ? When I click 'Setting' (next to the 'Load' button) and choose the Audio tab in version 2.58.44.152 it is not there. I am probably not looking in the right place. Thank you.

[marcelr]

When I used 2 pass VBR in Tmpgenc 2000kbps average with 2600 max and 200 min I got synchronisation video/audio problems again.

I cut the original avi in 2 using virtualdub.
Extract the audio
Used tmpgenc to encode, 2 pass VBR in Tmpgenc 2000kbps average with 2600 max and 200 and had sync. problems.

When encoding CBR at 2520 (more space), but no problems whatsoever.

What could cause this sync. problem ?

Also the suggestion to use the Tmpgenc's Layer II encoder at 64kbps is not possible. In tmpgenc, on the audio tab, the selection is grayed out and can not be altered.
Nevertheless I make great SVCD's (burned using Nero using VCD being not VCD compliant) but movies take up a lot of disks (normally 3 for an 1h, 20 min movie). It is not that disks are costly, it is just a hassle to get up every 25 minutes or so to swap disks.

Thank you.

[bugster]

You need to load the tmpGenc unlock template. This is called unlock.mcf and is to be found in the extras folder. As for your sync problems, could be lots of things, can you be more specific?

[Donny661]

The best way to get the most out of your cds is to use a bitrate calulator to get the right average bitrate so your cds will be full and you won't have wasted space. I usually try to fit up to 60min per cd for widescreen movies and a little less for full screen ones. As for audio at 64kbps, that sounds absolutely horibble. It's like listening to a stereo thats in a fish tank and down the hall. I wouldn' go any lower than 128 for layer II audio.

@marcelr

Try using the Source Range filter to select one half of the movie at a time, or encode your whole video and audio separate and use bbmpeg to mux it. With bbmpeg it will cut on the right filesize regardless of time. That way you can get even more quality out of 2pass vbr.