Post by Bill Pedersen
I would like to get the OpenVMS Boot Camp Session Audio recordings available
more quickly to the attendees, and eventually to the OpenVMS Community.
I really do not care what audio editing tool you prefer, as long as the
result is MP3 that is fine! I have used Audacity and find it easy to use
and also reliable. I know Keith Parris has also used Audacity - HINT Keith
you have a few cycles in LATE SEPTEMBER and EARLY OCTOBER?
I'd be willing to help. For reference and general interest I think your file formats are WAV that you collect. I'd use RAZORLAME to create a VBR MP3 from the raw audio files (it works in batch mode all files processed) then use MP3DIRECTCUT to top and tail the mp3 files. Freeware OK for commercial use.
As previously discussed here I'd like to improve the audio quality above telephone, and we can use VBR to economise on space but not quality. This is put in the LAME settings which drive the lame_enc.dll
For the more technically audio minded, the sample rate of the recorders is 16k, meaning maximum frequency recorded is 8kHz. They have a reasonable pick up but the main problem was the solid/metal hangers tended to clunk a bit when the presenter moved. I think the RLO settings I used were VBR 16-48 kbs mono with a lowpass filter applied at 7800 hz (to reduce HF aliasing) this is from memory. I experimented a bit. I think the files i ended up with were much better than the telephone quality and are double the size (roughly) of the current files.
mp3directcut is freeware for windows and it does not decode-reencode, it can just read, edit and write the raw mp3 frames. don't be afraid of VBR, its firmly in the MP3 specification.
So process I would use is:
Collect all WAV files, process ALL with Razorlame using settings agreed.
Top and tail / edit / split the MP3s using mp3directcut Save selection range as the name of the presentation in the directory needed.
Audacity is OK but its a bit of a sledgehammer. Preprocessing all to MP3 in batch should help. mp3dc can perform maximize operations too, pretty basic editing but all you really need. And it is fast. It can also just record to raw MP3 recordings too, mono, stereo etc. but under windows 7 if you try to use a USB input audio or digital capture device you need to change the _microphone_ properties to stereo... !
You need to find some of the LAME precompiles / binaries for both mp3dc and razorlame to operate. Instructions included in the readme's
(Yes I know its a bit off topic but someone may also find this useful. I do a LOT of audio work. Folks at the camp may have spotted me wandering around with a Tascam DR05 recorder and a plug in mike (Sony CS10) and my own session was recorded using this and the one available on my soundcloud page the link for which I previously provided. I also have a Marantz PMD661 v2 recorder so yep I'm serious about this stuff - field recordings.)
While I have not yet finalised my travel arrangements for this year, the weekend following there is a Gerry Anderson convention in the UK I'm probably going to !
Baldrick (emerging from the closet!)