Topic: How can I get information about a WAV file using an InputStream?

How can I get information about a WAV file using an InputStream?

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Posted By: Yoav_Gonen
Posted On: Tuesday, June 25, 2002 07:00 AM

I'm trying to get information about a WAV file, such as the encoding. Using this code: File f = new File("filename.wav"); AudioFileFormat fmt = AudioSystem.getAudioFileFormat(f); AudioFormat audioFmt = fmt.getFormat(); AudioFormat.Encoding enc = audioFmt.getEncoding(); System.out.println(enc.toString()); I get the desired information (e.g. ALAW). When I try this approach: File f = new File("filename.wav"); FileInputStream fis = new FileInputStream(f); AudioFileFormat fmt = AudioSystem.getAudioFileFormat (new BufferedInputStream(fis)); AudioFormat audioFmt = fmt.getFormat(); AudioFormat.Encoding enc = audio More>>

I'm trying to get information about a WAV file, such as the encoding. Using this code:

			

			File f = new File("filename.wav");
			

			AudioFileFormat fmt = AudioSystem.getAudioFileFormat(f);
			

			AudioFormat audioFmt = fmt.getFormat();
			

			AudioFormat.Encoding enc = audioFmt.getEncoding();
			

			System.out.println(enc.toString());

I get the desired information (e.g. ALAW). When I try this approach:

			

			File f = new File("filename.wav");
			

			FileInputStream fis = new FileInputStream(f);
			

			AudioFileFormat fmt = AudioSystem.getAudioFileFormat
			

			(new BufferedInputStream(fis));
			

			AudioFormat audioFmt = fmt.getFormat();
			

			AudioFormat.Encoding enc = audioFmt.getEncoding();
			

			System.out.println(enc.toString());

I get a different result (PCM_SIGNED). Any ideas why?

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Re: How can I get information about a WAV file using an InputStream?

Posted By: Christopher_Koenigsberg
Posted On: Tuesday, June 25, 2002 07:53 AM

Disclaimer: Shooting from the hip, closed book test, just guessing:

If you don't start with a file that really specifies a format in its header (have you tried "setFormat" and "setEncoding" first?), but rather if you start with an "empty object" ("new filename.wav") and try to "get" the format/encoding of the empty object, you're just going to get some defaults "inserted" somewhere along the way.

"ALAW" is crappy compressed old telephone quality audio, I think it's limited to 8 bit resolution (but also compressed), and 8KHz sample rate (thus the highest pitched sound it can pass is only 4KHz, like a telephone where you cannot tell the difference between an "f" and an "s" for instance).

"PCM SIGNED" is nice uncompressed linear 16-bit resolution, 44.1KHz (but takes a lot more bytes), e.g. standard CD-quality audio.

All you are determining is what comes through by default, given various kinds of "empty" input. Why don't you set up a real WAV file, with real (well, fixed-point or integer :-) audio content, and real format/encoding, and see what you get for it?

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