I need a way to bypass AC3 re-encoding requirement

Sebaz wrote on 12/26/2009, 7:48 AM
I have two AVCHD camcorders, one is a Canon and the other a Panasonic, this one from the professional line. For archiving purposes, I would like to throw a bunch of clips that I recorded until they're close to 4.38 GB to burn to cheap DVDs and not take up space in my hard drive. The problem is, while the video track gets accepted fine by DVDA 5.0b, the audio track does not, it tells me that recompression is required because "Media is not compliant with the disc format", which is not true, because it's simple stereo AC3 at 384 kbps in the case of the Panasonic and the same but 256 kbps in the case of the Canon. Is there a way to bypass this requirement? I scrolled through all of the internal preferences but I didn't see anything that might look related.

Thanks

Comments

musicvid10 wrote on 12/26/2009, 9:36 AM
A couple of options:

-- If you're just archiving, dump the material as a DVD data disc instead of authoring. Remember that DVDR does not have an indefinite shelf life, so it is not a permanent archiving solution.

-- Demux the material first. With separate video / AC3 audio files, DVDA "may" remux (prepare) without doing a rendering step.



Sebaz wrote on 12/26/2009, 10:17 AM
Thanks for the reply. Actually I forgot to put in my first post that I already tried the option of demuxing, and I'm still at the same point; the video elementary stream is accepted without re-encoding, but the ac3 file requires re-encoding. That's why I would like to find a way to tweak DVDA 5 so that it builds the disc without recompressing the audio.
musicvid10 wrote on 12/26/2009, 10:30 AM
Really.
Which demuxer did you use?
Can you upload a short clip of the orig. material somewhere?

I've got too much time on my hands this week . . .
Sebaz wrote on 12/26/2009, 11:00 AM
-- If you're just archiving, dump the material as a DVD data disc instead of authoring. Remember that DVDR does not have an indefinite shelf life, so it is not a permanent archiving solution.

Well, the reason I want to author a BD5 disc as opposed to just dump the files is that I want to be able to put the disc in my blu-ray player and watch them. With the software that came bundled with my Canon HF100, Pixela Imagemixer, I was able to throw all the clips in a basic timeline to remove the rough cuts and it smart-rendered perfectly to one file that then I could burn to a DVD-R and put in my blu-ray player. Unfortunately that software doesn't work completely in Windows 7. My favorite solution would be to edit in Vegas and then burn with DVDA, but Vegas 9.0c doesn't smart-render AVCHD very well.

I also tried MultiAVCHD, and while it does the job to some extent, the playback stops for about three seconds when it goes to the next take, something that didn't happen when I used Pixela Imagemixer.

Which demuxer did you use?

I used TSMuxer 1.10.6 (latest version available).

The link is: http://rapidshare.com/files/326228250/00000.m2ts.html

Thanks
musicvid10 wrote on 12/26/2009, 1:05 PM
Odd, if I pull an ac-3 using AVIDemux, it will work just fine in a DVD project, but wants to recompress in a BD project.
Same if I pull a direct stream copy in Super. Must be "something" in the stream attributes.

If it's going to recompress anyway, just as well do PCM, so no loss.

I'll keep playing when time permits.
Sebaz wrote on 12/26/2009, 1:55 PM
Odd, if I pull an ac-3 using AVIDemux, it will work just fine in a DVD project, but wants to recompress in a BD project.

Yea, the AC3 file works fine in a SD DVD project, but not in a BD one.

I would use PCM, but I don't want to because of two reasons: 1) it would reduce the amount of footage I can fit in an AVCHD DVD and 2)my Panasonic camera records at 21 Mbps VBR, which is already a little too high for BD5 or BD9 playback, and if I go from the 384 kbps AC3 to a bitrate three times higher, and that is likely to choke the blu-ray player.
musicvid10 wrote on 12/26/2009, 2:16 PM
Looking at three ac3 files, the two pulled above, and one rendered in Vegas, only the Vegas one doesn't want to reprocess in a BD project.

Curiously, the three files all look exactly the same in four different media information utilities. Not a bit of apparent difference. No additional tags as far as I can see.
Rob Franks wrote on 12/27/2009, 4:49 AM
Your work will get re-compressed just about every time (for blu ray) unless you use the certified pro encoder. DVDa is obviously reading something in the header in order to pick off the difference and I have often wondered if this didn't have something to do with some kind of obscure Dolby licensing requirement. Vegas pro/DVDa (pro) is after all one of the very few editing packages that comes with a certified dolby encoder right out of the box.
Sebaz wrote on 12/27/2009, 9:38 AM
Well, all that is good, but isn't there a way to tweak DVDA so that it bypasses that requirement?
musicvid10 wrote on 12/27/2009, 10:48 AM
Your work will get re-compressed just about every time (for blu ray) unless you use the certified pro encoder.

Interesting speculation, but not the case. If I import the OP's media into a BD project, and replace the audio with AC-3 stereo re-encoded in Super, it prepares in about 30 sec. without rendering either the audio or video. The libavcodec libraries in Super are open source, and not Dolby certified.

Same if I re-encode (not remux) in AVIDemux. Works perfectly.

Will keep digging as time permits, I'm sure there is a workaround hiding somewhere without re-encoding your files.
musicvid10 wrote on 12/27/2009, 12:00 PM
Sebaz,
(edited)
Have you tried:

1) Doing it all in ImgBurn?
--or--
2) Creating your BDMV folder in TSMuxer, then burning or creating your .iso in ImgBurn?
I just successfully burned a BDMV-DVD from your file by this method that plays on my laptop. Didn't know I could do this.