Locating and converting hidden audio

[psantucci]

A bit of a poser for me - in fact, the first task I attempted that couldn't be easily solved searching the forums.

I have an unencrypted BD file set. I can play all titles with PowerDVD 12.

One title is an audio interview. In PowerDVD, I see a still picture and on-screen text identifying the interviewer, and I can listen to the interview. Forward and reverse controls have no effect. The time progress bar does not move and it's start and end times both show 0:00:00. Navigating chapters in this tile moves the time bar, but does not affect audio playback. PowerDVD identifies the title as Title 6 and shows 22 chapters.

Handbrake didn't find the title at all.

MakeMKV finds it, and shows this information:

Title information
Source file name: 00005.mpls
Duration: 0:00:00
Chapters count: 22
Size: 5.0 MB
Segment count: 22
Segment map: 6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23, 24,25,26,27
File name: title_t01.mkv


Two tracks are listed, Video and PGS English Subtitles - forced only. No audio track is detected, and ripping with MakeMKV produces a one second long .mkv with the same still picture and on-screen text I see in PowerDVD, but no audio at all.

All clues welcome, and thanks.

[Cornucopia]

Wasn't sure if this was implemented on BD as it is with DVD, but possibly:

On DVD, you can have a asset that is an MPEGstill, series of MPEG stills in a slideshow that manual advance or retreat. Usually this does (should?) not have audio, but there have been known some trick discs which included audio. Since it wasn't supposed to be included, one experienced the same inability to control transport as you seem to be experiencing. Might be the same thing, might not. MPEG stills are equivalent to a JPEG (but would be .DAT in VCD, .VOB in DVD, and if they exist in BD would be .M2TS) and so would be very small, basically amounting to the size of the audio and a tiny bit more.

Not sure the best tool to use for this, but I would:
rip & demux each and every M2TS on the disc, then use VLC or similar to poke at each resulting elementary stream.


Scott

[psantucci]

Not sure the best tool to use for this, but I would:
rip & demux each and every M2TS on the disc, then use VLC or similar to poke at each resulting elementary stream.

Scott

Got it one!

tsDemux pointed at all files in \BDMV\STREAM produced a pile of elementary steam files - the audio I wanted ended up in "00028.track_4352.ac3". The highest numbered m2ts file in the source was 0027.m2ts. Interesting to say the least; I wonder if it was deliberate obfuscation or just the way audio-and-still is implemented in BD.

Problem solved, and my thanks.