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Java Forum / General / September 2006Playback of large WAV files...
I'm writing an application to play a large WAV file (say a couple hundred of megs), and allow the user to jump to / select a position in the file (e.g. 120 seconds into it) to start playback. The "skip" method of AudioInputStream always seems to return the value "4096", meaning it skipped 4K, no matter how far I actually tell it to skip. While a "Clip" would seem to be the ideal method, it doesn't support large files (over 5 meg?). Anybody else do something similar and want to share some advice? Or have any idea why "skip" doesn't skip to where I want it? > I'm writing an application to play a large WAV file (say a couple > hundred of megs), That is *huge*. What compression are these files using? If using an efficient form osf compression, the files will become much larger still, in memory. >..and allow the user to jump to / select a position in > the file (e.g. 120 seconds into it) to start playback. The "skip" [quoted text clipped - 3 lines] > While a "Clip" would seem to be the ideal method, it doesn't support > large files (over 5 meg?). Perhaps you need to break the files into smaller parts. > Anybody else do something similar and want to share some advice? Or > have any idea why "skip" doesn't skip to where I want it? The secret to that lies in the JavaDocs for the next-listed method. <http://java.sun.com/j2se/1.5.0/docs/api/javax/sound/sampled/AudioInputStream.htm l#available()> Andrew T. >> The "skip" >> method of AudioInputStream always seems to return the value "4096", >> meaning it skipped 4K, no matter how far I actually tell it to skip. [...] >> Anybody else do something similar and want to share some advice? Or >> have any idea why "skip" doesn't skip to where I want it? > The secret to that lies in the JavaDocs for the next-listed method. > <http://java.sun.com/j2se/1.5.0/docs/api/javax/sound/sampled/AudioInputStream.htm l#available()> available() will only tell you how many bytes can be read without blocking. You're free to request a read of more than that many bytes; it simply means your request will (probably) cause some blocking. To the OP, did you try values which are multiples of 4096? E.g. 8192 or 12288? Skip will "round" to the nearest frame. Maybe all your frames are 4096 bytes in size. - Oliver >> I'm writing an application to play a large WAV file (say a couple >> hundred of megs), > > That is *huge*. What compression are these files using? > If using an efficient form osf compression, the files will > become much larger still, in memory. Not really. A typical MP3 of a song is about 4 or 5 megs at 192kbps (exact size dependent on song length of course). With MP3 you can expect about a 5:1 compression ratio so the original WAV is approximately 50 megabytes. He is working with files then about 4 times the size of a typical song (~4 minutes long). He may very well be working with a 20 minute file with average bitrate or a shorter file with high bitrate. WAV is not usually compressed and contains data in PCM format which explains why files can be, as you say, *huge*. In reality, they aren't huge for that format because they aren't compressed. But are they huge compared to their compressed MP3 cousin? You could make that argument. Brandon Just wanted to follow up with a thank you for all of the feedback. The heads-up re: buffer size and blocking, and the references to JMF reading material were helpful and greatly appreciated! > I'm writing an application to play a large WAV file (say a couple > hundred of megs), and allow the user to jump to / select a position in [quoted text clipped - 6 lines] > Anybody else do something similar and want to share some advice? Or > have any idea why "skip" doesn't skip to where I want it? My guess is that you can't skip beyond the limits of the buffer in the AudioInputStream. I would try using a FileInputStream and see if that allows you to skip to where you want. Then read the file and write the data to a SourceDataLine.  SignatureKnute Johnson email s/nospam/knute/ > I'm writing an application to play a large WAV file (say a couple > hundred of megs), and allow the user to jump to / select a position in [quoted text clipped - 6 lines] > Anybody else do something similar and want to share some advice? Or > have any idea why "skip" doesn't skip to where I want it? If you're using JMF (or would like to), the book "Swing Hacks" by Marinacci and Adamson show how to progressively load and play audio media. The code samples there are excellent. Matt Humphrey matth@ivizNOSPAM.com http://www.iviz.com/ Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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