Lame MP3 Encoder编译为Android

Question

I want to compile the lame encoder for Android. How can I find the tutorials for Lame and its compiling for Android platform.

Thanks,

Answer 1

There used to be a good blog post on how to compile lame for Android, but for some reason it's been offline for a while and only available on some dodgy Chinese sites.

I'll just copy the content below:

porting compiling lame encoder to Android ARM arch using Android NDK

I was looking for a mp3 encoding application in Android Market, and found very few, the reason I think Android doesn't support mp3 encoding is because mp3 is patented technology. Another reason is I guess people prefer Java programming and Android SDK rather than Android native development kit.

Nevertheless compiling libmp3lame library for Android using Android NDK is very easy actually.

1. download Android NDK(also you need Android SDK and Eclipse with ADT plugin) and create simple project.
2. create directory called "jni" in your project's directory.
3. download lame sources, extract, copy all sources from directory libmp3lame to jni directory. Also copy lame.h which is located in include directory of lame sources.
4. create jni/Android.mk file. it should look like this:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)`
LOCAL_MODULE    := mp3lame
LOCAL_SRC_FILES := bitstream.c fft.c id3tag.c mpglib_interface.c presets.c  quantize.c   reservoir.c tables.c  util.c  VbrTag.c
   encoder.c  gain_analysis.c lame.c  newmdct.c   psymodel.c
   quantize_pvt.c set_get.c  takehiro.c vbrquantize.c version.c
include $(BUILD_SHARED_LIBRARY)

5. clean lame sources, remove what's left from GNU autotools, Makefile.am , Makefile.in , libmp3lame_vc8.vcproj , logoe.ico , depcomp , folders i386 , vector .
6. edit file jni/utils.h , and replace definition extern ieee754_float32_t fast_log2(ieee754_float32_t x); with this extern float fast_log2(float x);
7. go to the root directory of your Android project and run $pathtoandroidndk/ndk-build and you're done, you'll have limp3lame.so compiled.

Also, the following question on SO might be of interest for you, as it deals with some issues after compiling lame for Android:

• Invoking native functions of ported library

Answer 2

The above solution worked for me except:

• don't delete the vector directory from the source directory
• you can get rid of the compile warnings by adding a compiler flag: LOCAL_CFLAGS = -DSTDC_HEADERS