> I do take your message to imply that SoX will read no more samples > than the number of in a file total, so that, e.g., if you read the > same 10 blocks of samples and sox_seek() to the beginning of them > repeatedly, eventually your reads will fail. And in fact, if the > length of the file is 50 blocks, those reads will fail as soon as you > have done this 5 times. If this is not correct, please let me know!! > :) There is a difference between SoX the utility and libsox the library. I am not sure if SoX itself ever reads a block of audio more than once (I can imagina situations where it would), but that's not a constraint on what the libsox library can do. If it has a sox_seek(), then I suppose it does what the name says; in particular, it lets you read the same block of audio over ano over again as long as you keep seekign back. (Disclaimer: I have never used libsox directly, I only use SoX the binary.) > Now, in answer to your three questions and suggestion about libsndfile: > > (1) In fact, i didn't need to read the same samples multiple times, i > just needed to use them multiple times. > And it was possible for me to implement my own buffering scheme. > And that's what i ended up doing, > because in this particular case there is a pattern of access that > repeats. So it was possible to code around not being able to seek > freely. Well, that changes the whole premise. Is there anything left of the original problem then? > However it would have been easier not to do any buffering, and just > seek, and use the implicit buffering of the system. Using the same data again does not imply any buffering by itself. You sox_read() into an array and then use it as you wish (such as play it seven times). > A sort of analogous situation is with the file system and linux: if > you're reading through a file the OS will keep it in memory so you > don't have too much overhead just relying on the OS itself to seek > back and forth in a file --- the caching has already been done. You already _have_ the data in memory once you have sox_read() them, so I fail to see the analogy. Why would you seek back and read it again _from_the_file_ once you have it in an array? > (2) I'm doing this programmatically because i anticipate running the > program many times, and i want to be as sure of correctness as i can. > (In fact, i'm not actually programming it in C, but i'm using the C > calling conventions, and in principle i could certainly do this in C.) What makes you think that writing your own code will make your use of SoX more "correct"? > (3) I'm using SoX to do this because it is so good :) :). I also have > experience programming in SoX, although obviously i'm still learning. I still have no idea about what you want to do, eventually. You are asking about technicalities; what are you actually _doing_ ? > (4) libsndfile would definitely have been a possibility, but every > library has trade offs. As i understand it, libsndfile does not yet > support mp3, although that is on the road map. And it is possible > that there would be some other move that i was making that wouldn't > work in libsndfile. So i'd have to recode to see --- although as far > as i can tell, libsndfile and SoX are both excellent pieces of > software. I still have no idea about what you want to do. Jan ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Sox-users mailing list Sox-users@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/sox-users
