Hi, You defnitely should find an integer based only algorithm, it will be much faster! You need something designed for mobile CPUs
-niko On Mar 22, 2:30 pm, Rob Szumlakowski <rszum...@gmail.com> wrote: > Hi. We're implementing a program for Android phones that plays audio > streamed from the internet. Here's approximately what we do: > > 1. Download a custom encrypted format. This format is fixed and we > can't change it. > 2. Decrypt to get chunks of regular MP3 data. > 3. Decode MP3 data to raw PCM data in a memory buffer. > 4. Pipe the raw PCM data to an AudioTrack > > Our target devices so far are Droid and Nexus One. Everything works > great on Nexus One, but the MP3 decode is too slow on Droid. The audio > playback starts to skip if we put the Droid under load. We are not > permitted to decode the MP3 data to SD card, but I know that's not our > problem anyways. > > We didn't write our own MP3 decoder, but used MPADEC (http:// > sourceforge.net/projects/mpadec/). It's free and was easy to integrate > with our program. We compile it with the NDK. > > After exhaustive analysis with various profiling tools, we're > convinced that it's this decoder that is falling behind. > > Here's the options we're thinking about: > > 1. Find another MP3 decoder that we can compile with the Android NDK. > This MP3 decoder would have to be either optimized to run on mobile > ARM devices or maybe use integer-only math or some other optimizations > to increase performance. > > 2. Since the built-in Android MediaPlayer service will take URLs, we > might be able to implement a tiny HTTP server in our program and serve > the MediaPlayer with the decrypted MP3s from localhost. That way we > can take advantage of the built-in MP3 decoder. > > 3. Get access to the built-in MP3 decoder through the NDK. I don't > know if this is possible. > > Does anyone have any suggestions on what we can do to speed up our MP3 > decoding? > > -- Rob Sz -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en To unsubscribe from this group, send email to android-developers+unsubscribegooglegroups.com or reply to this email with the words "REMOVE ME" as the subject.
