Confused as to why a recode is required

ghealy

New member
The following applies to both VRDTVS v3 & VRDTVSh264 v4.

I have a SD analog movie I recorded using BeyondTV 4.4 & a Hauppauge WinTV USB2 TV tuner.

Ctrl-L shows:
File Name: D:\PVR\Burned\Banshee-2010-01-15-0.mpg
File Size: 6095300634 ( 5.68 GB )
Program Duration: 02:03:59.03
File Type: PS - MPEG2
Encoding: MPEG2
Video stream Id: xE0
Encoding Dimensions: 720 x 480
Display Size: 720 x 480
Aspect Ratio: 4:3
Frame Rate: 29.97 FPS
Bit Rate: 6.000 Mbps
VBV_Buffer: 224 KB
Profile: Main/Main
Progressive: Prog or Int
Chroma: 4:2:0
Audio Format: Layer 2
Audio Stream Id: xC0
Audio Bit Rate: 224 Kbps
Audio Sampling Rate: 48000 Hz
TS Mux Rate (bps): -1

Once I trimmed start & end and commercials, the total output time reads: 01:33:50:19

When I go to create DVD (Single Layer 4.7 GB), I'm told I must do a major recode and it shows Output Quality must be 6.12 Mbps (???)

Not understanding why it is trying to increase the output quality?

FWIW, I was able to get around this with a 'Save as' edited file with Chapters as a mpeg-2. Then reloading the saved mpg2 file with chapter marks. It creates a DVD without any recoding. (Curiously the output time reads: 01:33:50:14)

Was it something I did wrong? Just to repeat this problem happened in both v3 & v4.
 

phd

Super Moderator
Is it only happening with this one file?

It looks like you were really close to the limit of what will fit on a single layer DVD.
 

ghealy

New member
This is the first time I've noticed it.

What I find confusing is the original file was 2 hrs 3 minutes at 6 Mbps. After removing 30 minutes from it, VRDTVS wanted to increase the quality output to 6.12 Mbps.

Never had that happen before. When I'm over a single layer, it wants to re-encode to less than 6 Mbps.

Plus when I simply saved the file, it produced a file that was 4.13 GB definitely smaller than a single layer disc.
 

Dan203

Senior Developer
Staff member
Just change the output DVD size to DL. That will allow VRD to process the DVD without recoding and if it does actually fit on a SL DVD in the end then the burner will do it without complaining.

Dan
 

ghealy

New member
Thanks, Dan.

All I needed to do was save video as *mpg. The resultant file reloaded into VRDTVS burned to a single layer without any recoding.

The key item here was that VRDTVS wanted to *increase* the file's bit rate from the initially recorded 6 Mbps to an outputted 6.12 Mbps.

Realizing that the team is just a wee bit busy with the pre-release of VRDTVSh264v4, I appreciate you taking the time to comment.
 

Dan203

Senior Developer
Staff member
The value reported as the source bitrate is taken from the header of the file and does not necessarily reflect the actual bitrate used to encode the video. The only way to know the actual bitrate of a file would be to scan the entire file first, which would take way too long.

The calculation to decide whether or not to recode does not actually use that header bitrate, it's only used for display purposes. We calculate output size by looking at the size of the source file and calculating how much you're removing with the edits. Unfortunately this is not always 100% accurate because it does not take into account things that are not retained by the DVD output, such as multiple audio streams, subtitle streams and TS NULL packets. So sometimes we get false positives.

Although in your case the estimated output size was probably just close enough to the limit to cause a recode. Like I said above you get around this by telling the main DVD dialog that you're outputting a DL disc even if you intend to burn a SL disc. The burner portion does not care what setting you use. All it does is check to make sure there is enough space on the inserted disc to burn the DVD. If there isn't it'll pop up an error before it actually starts the burn.

Dan
 
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