Live Recording

[Carlos Mills]

Hi All,

This is nothing really new, but I wanted to share with you anyway. I
am
going to record a 32 track 24/48kHz live show next Tuesday (with SS, of course). So today I
did
a 2 hour non-stop recording for this session with SawStudio; and everything
ran very smooth (P4 2GHz, IDE-ATA 100 (8MB cache) HD 2x RME 9652). Each sound
file ended up with more than 1 GB (size) and the wave peak data were draw
instantly, right after hitting the stop button (after two hours). :-)
It's nice to be confident about your SS DAW!

Regards,

Carlos

[Bob L]

Carlos,

Glad to hear that things are stable.

One thing to watch out for is your max file size when doing live performance recordings... it is limited depending on your recording format.

SAWStudio uses 32 bit DWORD pointers to access the bytes in the wav files... this will limit the size of the largest individual file you can access correctly. 64 bit LONG DWORD pointers are available in Windows, but to use them for every file access and pointer calculation offset would seriously have affected the overall performance of even a tiny session, just for the purpose of allowing giant single files to be accessed... I chose the performance option over the giant file size. :)

You can calculate your max file size as follows:

SampleRate x BytesPerSample x Channels = BytesPerSec
BytesPerSec x 60 = BytesPerMin
4,294,967,296 / BytesPerMin = MaxMins
MaxMins / 60 = MaxHours

Example: 16 bit, 44100 stereo file (16 bits = 2 bytes per sample)

44100 x 2 x 2 = 176,400 Bytes Per Sec
176,400 x 60 = 10,584,000 Bytes Per Min
4,294,967,296 / 10,584,000 = 405.8 Max Mins
405.8 / 60 = 6.76 Max Hours ( I would stop at 6.5 hours or less)

Example: 24 bit 48000 stereo packed files (24 bits = 3 bytes per sample in packed format, 4 bytes per sample in unpacked format)

48000 x 3 x 2 = 288,000 Bytes Per Sec
288,000 x 60 = 17,280,000 Bytes Per Min
4,294,967,296 / 17,280,000 = 248.5 Max Mins
248.5 / 60 = 4.14 Max Hours ( I would stop at 4 hours or less)

You see how it goes... when approaching the max mark for your format... you must stop the recording at an opportune moment and pop open the Record Setup options from the Record Transport... simply change the name of the base file by adding an _a (or something similar) to the end of the current name. Then start recording again. All track files will be automatically adjusted to the new file names while still maintaining their individual track labels. You will now have multiple files placed down the timeline and can go through a full 24 hour timeline as long as each file never reaches beyond the max size.

Bob L

[Carlos Mills]

Carlos,

Glad to hear that things are stable.

One thing to watch out for is your max file size when doing live performance recordings... it is limited depending on your recording format.

SAWStudio uses 32 bit DWORD pointers to access the bytes in the wav files... this will limit the size of the largest individual file you can access correctly. 64 bit LONG DWORD pointers are available in Windows, but to use them for every file access and pointer calculation offset would seriously have affected the overall performance of even a tiny session, just for the purpose of allowing giant single files to be accessed... I chose the performance option over the giant file size. :)
Hi Bob, thanks for your reply! Your tips are VERY valuable. Opting for 32 bit DWORD, thus favoring performance over larger individuals file lengths are a great choice. As you showed below, we have over 8 hours of straight 24/48000 MONO files - or more than four hours of 24/96000 mono files. :p
I wonder how people handled live recordings with ADATs or DAs in the "past"... It should be fun to watch "it is time to change tapes" act :) . Maybe they worked with an extra set of modules, so they could "overlap" the period of tape changing... Then, if you double the number of modules for back up purposes and add at least two tapes for each machine, I bet I could build an State-of-The-Art-SS-DAWs with that money! :D

I have added your information to an excel file I made to calculate different audio files lengths... now, I can also know what is the maximum time allowed to record any file format (under windows of course...)


You see how it goes... when approaching the max mark for your format... you must stop the recording at an opportune moment and pop open the Record Setup options from the Record Transport... simply change the name of the base file by adding an _a (or something similar) to the end of the current name. Then start recording again. All track files will be automatically adjusted to the new file names while still maintaining their individual track labels. You will now have multiple files placed down the timeline and can go through a full 24 hour timeline as long as each file never reaches beyond the max size.

Bob L

Great idea. Much better than changing tapes! :D But I doubt I will need more than 4 hours non-stop...

Take care,

[Bob L]

Ooops... sorry to say my last message was incorrect... the Windows File Pointer function used actually is expecting a Signed DWORD value for the offset to accommodate negative and positive directions (it's been so long since I looked at that code :) )... therefore my examples were incorrect and the actual max file sizes are cut in half as follows:

SampleRate x BytesPerSample x Channels = BytesPerSec
BytesPerSec x 60 = BytesPerMin
2,147,483,648 / BytesPerMin = MaxMins
MaxMins / 60 = MaxHours

Example: 16 bit, 44100 stereo file (16 bits = 2 bytes per sample)

44100 x 2 x 2 = 176,400 Bytes Per Sec
176,400 x 60 = 10,584,000 Bytes Per Min
2,147,483,648 / 10,584,000 = 202.9 Max Mins
202.9 / 60 = 3.38 Max Hours ( I would stop at 3 hours or less)

Example: 24 bit 48000 stereo packed files (24 bits = 3 bytes per sample in packed format, 4 bytes per sample in unpacked format)

48000 x 3 x 2 = 288,000 Bytes Per Sec
288,000 x 60 = 17,280,000 Bytes Per Min
2,147,483,648 / 17,280,000 = 124.3 Max Mins
124.3 / 60 = 2.07 Max Hours ( I would stop at 2 hours or less)

Sorry about that. :o

Bob L

[AudioAstronomer]

Would it be possible to have saw automatically load a new file when the limit Is almost reached? Almost every other software does this. Opens a new file and begins to overlap the recordings with markers.

Not that it really matters to me at this moment, most live recording I do has nice breaks every 30-60 minutes. But one day this may cause a problem :) Particularly for potential users who expect the software to do this automatically.

[Bob L]

An automatic file overlap is on the ToDo list, but a little more testing is involved because there are a lot of buffers and pointers that may be affected during the non-stop recording file changeover.

Bob L

[AudioAstronomer]

An automatic file overlap is on the ToDo list, but a little more testing is involved because there are a lot of buffers and pointers that may be affected during the non-stop recording file changeover.

Bob L


good to hear :) Anyone doing live recording professional hasw redundancy anyways, so I dont see it as a big deal ;)

[Bob L]

By the way... I just finished re-doing some code in how I am handling the Windows File Pointer function and managed to get the full unsigned DWORD extension without having to give up any MT performance...

The max file size has just doubled back to the original values I posted in my first message in this thread... Version 3.8... coming soon. :)

Bob L

[Carlos Mills]

By the way... I just finished re-doing some code in how I am handling the Windows File Pointer function and managed to get the full unsigned DWORD extension without having to give up any MT performance...

The max file size has just doubled back to the original values I posted in my first message in this thread... Version 3.8... coming soon. :)

Bob L

This is great. This way I don't even have to change my first excel sheet...
By the way, I am just back from the live recording session. Everything ran perfectly. We did 29 tracks 24/48 for about 1 hour and 40 minutes and everybody was really happy with the results.

Thanks again.

[Bob L]

Good job... hopefully we'll be able to hear a taste of the final mix through some mp3 files. :)

Bob L

[Carey Langille]

Maybe if ""SAWRadio"" comes back, we can ALL hear it???

[Carlos Mills]

Good job... hopefully we'll be able to hear a taste of the final mix through some mp3 files. :)

Bob L

Sure Bob. If we have the SAW radio again, like Carey suggested, I can upload it later on.
This is a guy who made 3 or 4 big hits in the 80's here in Brazil (His name is Dalto). The show was filmed and will probably genrate a DVD also...

Take care.

[Bob L]

Jeanne and I have been working on some ideas, like Lewis's SAW Radio concept.

We have not settled on a final solution yet, but it is on the ToDo list.

Bob L

[Shawn]

Hey Bob,

Have you or Jeanne checked out www.recordingproject.com ?

They have a section of the discussion forums over there called 'the listening room", where members can upload MP3's in a thread, and then the members can all listen and offer suggestions/comments, and even sometimes leads to collaborations between members.. I think it's pretty cool.

:)

[Bob L]

That is exactly the kind of thing we were thinking about...

They did a nice job with that.

Bob L

[Shawn]

That is exactly the kind of thing we were thinking about...

They did a nice job with that.

Bob L

I think they did a nice job too, the way it's setup is pretty innovative (I think), I've never seen any other web forum have anything quite like it, in most places you'd have to get your MP3 hosted somewhere, and then post a link to it, being able to post an MP3 right in a thread is about as user friendly as it gets.

:)

[IraSeigel]

Carlos,

Glad to hear that things are stable.

One thing to watch out for is your max file size when doing live performance recordings... it is limited depending on your recording format.

SAWStudio uses 32 bit DWORD pointers to access the bytes in the wav files... this will limit the size of the largest individual file you can access correctly. 64 bit LONG DWORD pointers are available in Windows, but to use them for every file access and pointer calculation offset would seriously have affected the overall performance of even a tiny session, just for the purpose of allowing giant single files to be accessed... I chose the performance option over the giant file size. :)

You can calculate your max file size as follows:

SampleRate x BytesPerSample x Channels = BytesPerSec
BytesPerSec x 60 = BytesPerMin
4,294,967,296 / BytesPerMin = MaxMins
MaxMins / 60 = MaxHours

Example: 16 bit, 44100 stereo file (16 bits = 2 bytes per sample)

44100 x 2 x 2 = 176,400 Bytes Per Sec
176,400 x 60 = 10,584,000 Bytes Per Min
4,294,967,296 / 10,584,000 = 405.8 Max Mins
405.8 / 60 = 6.76 Max Hours ( I would stop at 6.5 hours or less)

Example: 24 bit 48000 stereo packed files (24 bits = 3 bytes per sample in packed format, 4 bytes per sample in unpacked format)

48000 x 3 x 2 = 288,000 Bytes Per Sec
288,000 x 60 = 17,280,000 Bytes Per Min
4,294,967,296 / 17,280,000 = 248.5 Max Mins
248.5 / 60 = 4.14 Max Hours ( I would stop at 4 hours or less)

You see how it goes... when approaching the max mark for your format... you must stop the recording at an opportune moment and pop open the Record Setup options from the Record Transport... simply change the name of the base file by adding an _a (or something similar) to the end of the current name. Then start recording again. All track files will be automatically adjusted to the new file names while still maintaining their individual track labels. You will now have multiple files placed down the timeline and can go through a full 24 hour timeline as long as each file never reaches beyond the max size.

Bob L

Hi,
This thread is almost 2 years old. Has anything changed in the intervening time?
Does the above data hold true for Basic and for Lite?

Thanks,
Ira Seigel

[Bob L]

This still holds, although I effectively doubled the limit to 4 gigs somewhere along the way.

Bob L