Tool to locate movie file audio gaps?

[fvisagie]

Hi All,

Here and there my rendered DV AVI contains annoying 1-frame audio gaps on clip boundaries, caused by the editor. Currently I'm stepping through the movie looking for these and fixing them up (in another editor ).

Without going into the details, for this particular project analysing either DATECODEs or timecodes isn't a failsafe way of detecting clip boundaries. So I'm using VirtualDub's scene detection to help get to clip boundaries quicker, and then I look for gaps in the audio waveform there.

However, it occurred to me that - identifying audio gaps being the primary objective - perhaps there's some tool that could do that directly. I've had a look at the listings but must have missed it if there is something suitable.

Do you know of any tool that can locate audio gaps? (If need be I could extract the soundtrack to a separate audio file, but then ideally the tool would generate a listing of gaps in subtitle format or something to make back-referencing to the video easier.)

Many thanks,
Francois

[fvisagie]

In case there's another lost soul looking for a solution to this problem like me, I ended up with an alternative approach which in hindsight I much prefer. It works for timecoded DV video files. (The footage without timecodes in this project I just did manually).

Here are the steps:

1. Use the Avisynth-based utility at http://forum.doom9.org/showthread.php?p=1317470#post1317470 to generate an ASS subtitle format scene file for your video
2. In Aegisub, open the subtitle scene file, open the video and click the toggle button to enable auto-scroll of video, open its audio and set the waveform display to amplitude (i.e. not spectrum mode)
3. In VirtualDub, open the subtitle scene file (with VSFilter's TextSub - http://sourceforge.net/projects/guliverkli2/files), open the video and turn on audio waveform display. The subtitles and audio waveform aren't necessary here but simplify accurate navigation and cross-referencing.
4. In Aegisub, step through the scenes by moving from subtitle to subtitle, and at each check the audio waveform for any gap
5. For any gaps you identify, in VirtualDub navigate to the same frame and delete it

That's it, enjoy!

Kind regards,
Francois