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  #1  
Old 2007-12-08, 03:54 PM
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Question MPEG-2 to DVD Question

Some time back, I received a DVD-R in trade which contained 7 .mpg files corresponding to the 7 episodes of the Transatlantic Sessions 2 series broadcast by BBC4 in 1998. I have no lineage info to speak of, but I used TMPGEnc DVD Author 3 to: a) merge the 7 individual .mpgs into a single, 3-hour DVD video; b) add chapter points for the 46 tracks; and c) create LPCM audio in the final product. It was left in its original PAL format, and the resulting VIDEO_TS folder is 5.98 GB in size. I also noticed that the average bitrate for the newly-created video is only 2877 kb/s, even though the audio/video quality seem very clean and crisp. I suspect this was some kind of a digital capture of a more recent rebroadcast of these shows, in consideration of its quality and apparent absence of VHS artifacts.

Therefore, my questions are as follows:

1) If I reauthor the originals again to AC3, the resulting video would become a dvd5. In that this is coming from MPEG-2 files (of unknown source and unknown past manipulation), was there even any reason to go LPCM to begin with? Has the audio not already been rendered lossy, and therefore, going with AC3 on this new video would actually provide the same audio quality while allowing for it to be burned to a single-layer disc?

2) Is the low bitrate suggestive of past re-encoding, etc., or was that merely the typical result of recording these shows as .mpgs to begin with?

3) Is there anything I've mentioned in the above inquiry that would preclude this fine video from being uploaded at TTD, particularly if I were to reauthor it to AC3 to make it's size more appealing to downloaders? I've not found this series for download anywhere else, and it would seem like a very nice one to put up (Jerry Douglas, Aly Bain, Ricky Skaggs, etc., in top form), if possible.

Thanks in advance for any suggestions/advice on this!

P.S. - If anyone knows where to find torrents for either Transatlantic Sessions 1 (~1996) or 3 (~2007), please reply!
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  #2  
Old 2007-12-08, 06:06 PM
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Re: MPEG-2 to DVD Question

You don't mention what was the audio format of the original files. If it was a DVB (digital broadcast) they should be in MP2. However, if it was recorded in 1998 I believe you files come form a VHS transfer, so the audio was probably in AC3.

If you converted it to LPCM then stay with it. TMPGEnc AC3 codec is good but not the best. It cuts in most cases everything over 16 kHz or on a noisy material even lower, so you may end with a bit more dull sounding audio, and of course it will be (double?) lossy.

I'd rather divide the show into 2 discs than make any (re)conversion. BTW: DVD Author 3 always slightly re-converts video stream. I'm not 100% sure but seems that if the material is flagged as coming from TMPGEnc codec it is left untouched.

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Originally Posted by Dudogger View Post
2) Is the low bitrate suggestive of past re-encoding, etc., or was that merely the typical result of recording these shows as .mpgs to begin with?
It can be a DVB if recorded no earlier than 3-4 years ago as before there was no equipment do it.
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  #3  
Old 2007-12-09, 04:28 AM
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Icon6 Re: MPEG-2 to DVD Question

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Originally Posted by pawel View Post
You don't mention what was the audio format of the original files. If it was a DVB (digital broadcast) they should be in MP2. However, if it was recorded in 1998 I believe you files come form a VHS transfer, so the audio was probably in AC3.

It can be a DVB if recorded no earlier than 3-4 years ago as before there was no equipment do it.
The audio format of the original .mpg files is MPEG-1 Layer 2. Also, I certainly know DVB only goes back so far (not to 1998, for sure), which is why I suggested this might be a captured BBC4 rebroadcast from more recent years. At this point, I only have what I have, and would like to convert and present it in the most optimal fashion. So my questions all remain the same:

1) Doesn't converting to LPCM here solve nothing but just consuming more disc space by the resulting video?
2) Why might the bitrate be so low? And does that suggest a VHS recording in the lineage?
3) Can I upload this to TTD once converted to a DVD video format, or has it been potentially modified too much at this point?

Thanks again...
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Old 2007-12-09, 06:03 AM
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Re: MPEG-2 to DVD Question

Quote:
Originally Posted by Dudogger View Post
The audio format of the original .mpg files is MPEG-1 Layer 2.
So they are in VCD or SVCD resolution. The answer is simple: here and on Dime such files can be seeded in their original format only, and not bloated to DVD (which doesn't make sense).

The only allowed compression for S/VCD audio is mpa.
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  #5  
Old 2007-12-09, 12:55 PM
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Re: MPEG-2 to DVD Question

it would really help to know the actual specs of the original .mpg files...use GSpot if yer on a PC, MpegStreamclip on a Mac and post the results here

Quote:
Originally Posted by Dudogger View Post
1) Doesn't converting to LPCM here solve nothing but just consuming more disc space by the resulting video?
correct...its like taking a mp3 and converting it to wav, yer still not gonna get back whats been lost due to the original compression...
Quote:
Originally Posted by Dudogger View Post
2) Why might the bitrate be so low? And does that suggest a VHS recording in the lineage?
no, it has nothing to do with previous encodings/compression...the DVD has a low bit rate because it was encoded it that way...you should be able to set the bit rate to whatever you want
Quote:
Originally Posted by Dudogger View Post
3) Can I upload this to TTD once converted to a DVD video format, or has it been potentially modified too much at this point?
depends, really need to know more about the original mpg files before i could give ya a definitive answer
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  #6  
Old 2007-12-11, 10:33 AM
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Re: MPEG-2 to DVD Question

P.S. - If anyone knows where to find torrents for either Transatlantic Sessions 1 (~1996) or 3 (~2007), please reply!

Transatlantic Sessions season 3 DVD is released next week 17th December by Music of Scotland , Volume 1 CD has already been released and volume 2 to follow in January next year. If you haven't seen all of it yet , Darrell Scotts "You'll never leave Harlan Alive" is superb- the house band is just awesome.
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  #7  
Old 2007-12-11, 02:33 PM
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Icon6 Re: MPEG-2 to DVD Question

Quote:
Originally Posted by AAR.oner View Post
it would really help to know the actual specs of the original .mpg files...use GSpot if yer on a PC...
...depends, really need to know more about the original mpg files before i could give ya a definitive answer
For one of the seven original .mpgs, GSpot gives the following info:

Size: 627MB
Sys Bitrate: 3052 kb/s VBR
Audio Codec: MPEG-1 Layer 2
Info: 48kHz, 256 kb/s tot, stereo
Video codec: MPEG-2
Length: 28:23:240
Frames: 42,581
Kbps: 2796
Qf: 0.270
Pics/s: 25.0
Frames/s: 25.0
Fields/s: 50.0
PAL: 720x576
Sar: 1.250 (5:4)
Par: 1.422 (~10:7)
Dar: 1.778 (16:9)
Resizing: None, Already DVD format

Please let me know if there's anything else I can provide. Thanks.
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  #8  
Old 2007-12-11, 02:40 PM
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Thumbs up Re: MPEG-2 to DVD Question

Quote:
Originally Posted by kayjaybee View Post
Transatlantic Sessions season 3 DVD is released next week 17th December by Music of Scotland , Volume 1 CD has already been released and volume 2 to follow in January next year. If you haven't seen all of it yet , Darrell Scotts "You'll never leave Harlan Alive" is superb- the house band is just awesome.

Excellent info - Thanks! Thus far I've only seen Season 3 via video stream from the RTE Television site here: http://www.rte.ie/tv/transatlanticsessions/.
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