Add new audio to DVD without re-encoding video??

[vulture99]

Hi,

I have a DVD of a live music performance. It was made using the internal camera mic (poor audio), and I want to replace the audio with a separate recording that was made using pro audio gear.

I want to do this without re-encoding the video at all (direct stream copy of the video, essentially). I demuxed using PGCDemux and loaded the .m2v file into Adobe Premiere Pro, where I synced the video with the new audio. I can export the project as MPEG2-DVD and burn it to a DVD and that works ok; however, I think Premiere re-encodes video when exporting.

Can I do this project in Premiere without re-encoding the video? Is there a way to do a direct stream copy of the video in Premiere? If not, what other tools should I use? I am fairly new to all of this (except the audio part), so please excuse any newbie blunders.

Thanks very much,
vulture99

[jman98]

Yes, you can do this rather easily in this guide:
https://forum.videohelp.com/topic275603.html
Note that this guide covers adding new subtitles to an existing DVD, but the process is basically the same, just replace the original audio file with the new and skip the subtitle stuff.

I can't help you to do this in Premiere, but Premiere is not necessary for this task.

[filmboss80]

As long as you do not edit the original .m2v file (thus changing running time), you do not need to save the Premiere project as an MPEG-2. After you sync the new audio to the original video, simply export the audio timeline to a wav file, then use Aften with the WAV to AC3 Encoder GUI to convert the wav to ac3. Remux the new ac3 file with the original m2v video file using ImagoMPEG-Muxer or any DVD authoring software.

Other than Premiere, all software mentioned is free and available in the Tools section of this site.

[vulture99]

Thanks. I have used most of those tools already (demuxed using PGCDemux, built new DVD structure using IFOEdit). So the part I'm wondering about is Muxman. I need to sync up the new audio track to the video, then clip several seconds off the beginning and end of the entire project (otherwise the beginning will have several seconds of video with no audio, and the end will have the opposite). Will the "Delay" function in Muxman allow me to do the syncing precisely and using Muxman can I also clip off each end of the project?

Thanks.

[vulture99]

As long as you do not edit the original .m2v file (thus changing running time), you do not need to save the Premiere project as an MPEG-2. After you sync the new audio to the original video, simply export the audio timeline to a wav file, then use Aften with the WAV to AC3 Encoder GUI to convert the wav to ac3.

Hmmm, that sounds promising. Except I need to clip off each end of the project (see my last post). Not sure I could use the original .m2v file then...? But I like this idea.

[filmboss80]

Okay, before you demux with PGCDemux, cut the ends off the project with MPG2Cut2. That way your audio stream will be cut exactly in time with the video. THEN demux and do the re-syncing with Premiere, again exporting only the new audio track. Convert wav to ac3 as mentioned earlier and remux. MPG2Cut2 will cut the VOB/mpg and save to a new file without reencoding.

[poisondeathray]

Is your 2nd audio lined up nicely and linearly with equivalent duration? or do you have to do fancy shifting on the timeline, and/or compensate for breaks?

If it's the easy scenario, you could bypass Premiere all together which would save you 1 round of audio quality loss re-encoding.

If this is the case, you could enter the linear delay when muxing, and clip the end off with an editor like mpg2cut2 (GOP accurate) or videoredo (frame accurate with re-encoding around the GOP cut site)

[vulture99]

Okay, before you demux with PGCDemux, cut the ends off the project with MPG2Cut2. That way your audio stream will be cut exactly in time with the video. THEN demux and do the re-syncing with Premiere, again exporting only the new audio track.

Thanks, but I am confused - the new audio stream will not be exactly in time with the video until I sync them, so how can I cut the separate audio and video files to the right lengths before doing the syncing? If I cut first and then sync, I will likely still end up with audio or video gaps at either end of the project. Maybe I'm totally misunderstanding

[vulture99]

Is your 2nd audio lined up nicely and linearly with equivalent duration? or do you have to do fancy shifting on the timeline, and/or compensate for breaks?

The 2nd audio just requires a 2.20 sec shift at the beginning to match up with the video. Then it's smooth sailing for the rest of the project. (I already edited the audio portion in Sound Forge to fix one dropout that was causing problems.)

I attached an image of the initial offset to give you an idea of what I'm talking about. You'll see that at the beginning of the project there is 2.20 sec of video with no audio and I need to trim a bit more - basically need to remove the first 5 seconds of video and the related audio portion as well. And do a similar operation at the end of the project.

Thanks for all the help guys, I appreciate it.

[poisondeathray]

OK so schematically you have something like this? :

VVVVVVVVVVV
     AAAAAAAAAA

But the central portion is lined up once you have the proper delay?

Looking at the screenshot, if the audio is already in .wav format, you won't lose anything by using Premiere, because you will be re-encoding to AC3 anyway

You could do this all in avidemux quite easily as well
1) Open your original file with "bad audio" or if you want you can use the .m2v

2) Audio=>main track=>audio source (select external wav or external AC3, whatever your "good" audio format is) and "point" to the location

3) Video sidebar=>copy if you already have AC3, or if it was WAV originally, change it to AC3 and configure the bitrate settings (it also uses aften encoder which provides good quality)

4) Audio sidebar=> checkmark shift end enter value in ms, press enter . A negative delay is a positive shift. You can fine tune it on the fly by pressing play, and re-adjusting the value until it's perfect

5) Format sidebar to MPEG-PS (A+V)

6) Mark the central section you want to keep by using mark in/mark out "<<" ">>"

7) Press save with extension (e.g. "myfile.mpg")

You can not use this synced .mpg to put into any DVD authoring tool e.g. GUIforDVDAuthor, DVDAuthorGUI, DVD-Lab Pro etc....