Appreciate your very informative advice. This is proving to be quite a learning experience for me. My knowledge of all this is limited, & the learning curve seems to grow. But I'm giving it a shot.
Used Disk Warrior & Disk Utility as advised, to repair & clean up whatever damage there might be on my Mac. But still no luck, nor any problems located w/ either tool. However, your comments re: the unrecognized .ac3 file pointed me in the direction to find Handbrake, a video transcoder, & MPEG Streamclip, a video converter.
In TOAST video window, after conversion w/ MPEG Streamclip, it read:
Video: DV/DVCPRO-NTSC, 720x480, 29.97fps
Audio: 16-bit, Stereo, 4800Hz
Saving as Disc Image resulted with a Roxio Converted Items file that contained:
224kBit.44kHz.P0.0-17350.D230.m1a Kind: MPEG Audio Size: 15.5 MB
NTSC.352x240.11Mb.4x3.M0.H0.T1.P1.0.17350.D230.m1v Kind: MPEG-1 Video Size: 79.5 MB
As you can see, there were no .ac3 nor .m2v files. In this case, the audio Kind was not plain text. However, the end result would still NOT play audio with either DVD Player or QuickTime. Both stated the media type was not supported.
Tried exporting MPEG Streamclip to QuickTime, DV, AVi, but all resulted with: audio media error.
Also tried saving MPEG Streamclip conversion of Final Cut Express file to .mov file, then repeated the TOAST process. But once again, NO audio in playback. Tried again, after trashing Prefs a 2nd time. This produced an audio disc image that played only white static noise. Go figure....
Handbrake's info indicates that much experimenting might result in success. It's very time consuming, but may be worth a try?
Further research online has also led me to conclude the following might possibly be the problem:
Apple has disabled the audio playback ability.
Can the QuickTime MPEG-2 Playback Component play back AC3 audio?
No, MPEG-2 files containing AC3 audio cannot be played back with the QuickTime MPEG-2 Playback Component.
And so it goes. What do you think? Thx again for your assistance.