A generation loss & TMPGenc related question.

[The Winster]

Here is the question in short: -
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Does TMPGenc use "Direct Stream Copy" for video when the change made to the video is none at all or just elimination of bands and the source & destination format specifications are same. Also, does it support Direct Stream Copy, if the project requires no modification? Or does it always process the source?

I am asking this question, because VirtualDub supports "Direct Stream Copy" which assures me that no generation loss has occured. But it cant encode into MPG and so, I need to use TMPGenc. ;(

Here is the question in detail: -
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If i use TMPGenc to re-encode a MPG file (with Pal VCD specifications) into the same MPG specifications but replacing the black bands at the top and bottom of the video with mask, would there be a considerable generation loss? Would there be a quality loss?

If I keep the video source MPG (with PAL VCD extensions) as is, but change the audio source to a MP2 (with 44 KHz and 224 KBPS bitrate) file and then re-encode into MPG with PAL VCD extensions, would there be any generation loss? Would there be a quality loss?

[AbsoluteDestiny]

No it does not use Direct Stream Copy.

Also, we have seperate tech forums below for questions like this.

[Qyot27]

If I keep the video source MPG (with PAL VCD extensions) as is, but change the audio source to a MP2 (with 44 KHz and 224 KBPS bitrate) file and then re-encode into MPG with PAL VCD extensions, would there be any generation loss? Would there be a quality loss?

'File' menu->MPEG Tools->Simple Demultiplex

That will seperate the audio from the video, so you can reencode the MP2 seperately. Then go to the Simple Multiplex tab and combine the two again, assuming your video source is standard 1150kbps at 352x288. Make sure that the drop-down menu says 'MPEG-1 Video-CD', though, or else it won't register properly in the VCD authoring program (at least if you're using Nero).

Alternatively, you could use the Simple Demultiplex option and then use the 'MPEG-1 Video-CD (non-standard)' option on the Simple Multiplex screen to put the two back together. This doesn't require reencoding anything, unless the bitrate of the video or audio is too high for a DVD player to correctly playback in VCD mode.

If you simply want to cut parts away from the MPEG file, use the Merge & Cut screen under MPEG Tools (you'll still have to set the corresponding Video-CD flag, though). All of the MPEG Tools are TMPGEnc's 'Direct Stream Copy' functions, if you will.