What Is A Broadcast Wave?

Can someone please tell me about the Broadcast WAV file (BWF)? I have only just come across this today, and I'm thinking I need to know what this is. And supposing that I need to use these, does Audition support this format?

Thanks  

The Broadcast WAV format is all about metadata - basically, it's intended to add relevant information in an agreed format to a file. You can download all the documents about it from here. The good news? Yes, Audition supports it - View>Wave>EBU extensions and Chunk.

Thanks steve, I downloaded one of the examples form the link you gave me.

Presumably you can see the metadata of a broadcast wave in View > Wave Properties > EBU Extensions tab in Audition.

I'm trying to work out what this data is. Is it this part under Coding History:

A=PCM,F=48000,W=16,M=stereo,T=PCX9
A=PCM,F=44100,W=16,M=stereo,T=Goldwave software

So it's telling me which software was used to create the file?

[3. Coding History field in the <bext> chunk]

Well, yes it is, but it's not obliged to do so... Here is an extract of an overview of the relevant spec:

3. Coding History field in the <bext> chunk
The strings used in the coding history field are specified in EBU Recommendation R98 [3]. This information is
repeated below for convenience.
A=<ANALOGUE,....> Information about the analogue sound signal path
A=<PCM,.....> Information about the digital sound signal path
F=<48000, 44100, etc.> Sampling frequency [Hz]
W=<16, 18, 20, 22, 24, etc.> Word length [bits]
M=<mono, stereo, 2-channel> Mode
T=<free ASCII-text string> Text for comments[/list:u][/color]
So as you can see, the T info could be anything you wanted, really...

Well, yes it is, but it's not obliged to do so...

I got most of that, thanks. I don't know what you mean by obliged.

I got most of that, thanks. I don't know what you mean by obliged.

So it's telling me which software was used to create the file?

and I said

"Yes, but it's not obliged to do so" - obliged, as in Collins 3rd definition 'to do a favour or service to (someone)'. There is no obligation placed on the Broadcast WAV format to tell you what SW was used to create a file - it just happened to be in the free text (comments) field...

Yes, thanks Steve, good explanations. Just threw me a little on the over-dramatisation of the "obligations" of a piece of software, LOL  . You see "obligation" is a moral or legal requirement or "duty", and it implies sentience (a self-awareness) and a decision process of sorts, and machines do not have sentience. A machine cannot decide whether it's the right thing to do to perform a "duty", according to a "moral obligation". Therefore "obligation" cannot be applied here  

[no]

You see "obligation" is a moral or legal requirement or "duty", and it implies sentience (a self-awareness) and a decision process of sorts, and machines do not have sentience. A machine cannot decide whether it's the right thing to do to perform a "duty", according to a "moral obligation". Therefore "obligation" cannot be applied here  

Which is why I said "There is no obligation placed on the Broadcast WAV format". There is a defined difference between the meaning of the word 'obliged', and the word 'obligation' - look them up - you'll see what I mean. But if SW claims to conform to a standard, then at least one of the definitions of obligation can be applied to the purveyors of it, at least, but not to the SW itself, which is obviously amoral. And in this particular case, the EBU do not place any obligation on the purveyors of SW claimed as conforming to Broadcast WAV standards to provide details of the originating SW for a file.

And BTW, I studied linguistics as a component part of my BA (Hons). I would have very little excuse for not being aware of the difference in meaning!

Please help my ignorance here concerning BWF: I thought one of its major features was a time stamp to allow it to be re-synchronized via timecode.  Yes? No? Maybe?

[TimeReference]

Please help my ignorance here concerning BWF: I thought one of its major features was a time stamp to allow it to be re-synchronized via timecode.  Yes? No? Maybe?

Not quite - if you look at section 1.3 of the version 1 document, you'll find that there is a field that allows you to put in the start absolute SMPTE TC counting from midnight, but this isn't necessarily very helpful info (but see below). The way they define it is as follows:

TimeReference This field contains the timecode of the sequence. It is a 64-bit value which contains the first sample count since midnight. The number of samples per second depends on the sample frequency which is defined in the field <nSamplesPerSec> from the <format chunk>.[/list:u][/color]
But obviously, editing can screw this rather more than somewhat. I wouldn't describe the feature as major - a feature, certainly, but not that significant as far as I'm personally concerned. I think that for some users it comes into its own when recording live feeds or telcos from journos in the field - if it's breaking news, it becomes a lot easier to construct meaning from this if the absolute timing of each feed is known, and can be fitted into a historical sequence.

Be careful with the Swedish Radio examples. They used to feature one which had a header that didn't match the internal format. I assume they are still the same, but haven't time to download and try tonight.

The reason this is significant is that CEP reads the header and not the internal compressed data block headers, and thus plays the file at the wrong speed.

The history of the file shows that the error occurred when the sample rate was changed by a hardware device which failed to update the header.

Because of the ability of CEP to translate files between formats it has to read and act on the header info.

I think that Wildduck's particular example exemplifies some of the potential snags and pitfalls with the Broadcast WAV format - this is a good example of where ignorance is not bliss...

And BTW, I studied linguistics as a component part of my BA (Hons).

And I have a masters degree in anthroplogy, that's a research degree in which .. the deep study of etymology is totally useless in the pursuit of creating compelling audio recordings  

Well, thanks Steve, now I know a little bit about the broadcast wave format, should it ever come up in polite conversation

And I have a masters degree in anthroplogy, that's a research degree in which .. the deep study of etymology is totally useless in the pursuit of creating compelling audio recordings  

Oh dear. My Masters is in Acoustics and Noise Control - and, er, has some practical relevance...

Except when you were studying Noise Control, they weren't expecting you to apply it to forum moderation, were they?  Just how long have forums existed, anyway?