Using Lame function hip_decode in Android NDK to decode mp3 return 0 - android-ndk

Question

I am using Lame's mpglib to decode mp3 to PCM in Android NDK for playing. But when I called hip_decode(), it returen 0 meaning that "need more data before we can complete the decode". I had no idea how to solve it. Can someone helps me? Here is my code:
void CBufferWrapper::ConvertMp3toPCM (AAssetManager* mgr, const char *filename){
Print ("ConvertMp3toPCM:file:%s", filename);
AAsset* asset = AAssetManager_open (mgr, filename, AASSET_MODE_UNKNOWN);
// the asset might not be found
assert (asset != NULL);
// open asset as file descriptor
off_t start, length;
int fd = AAsset_openFileDescriptor (asset, &start, &length);
assert (0 <= fd);
long size = AAsset_getLength (asset);
char* buffer = (char*)malloc (sizeof(char)*size);
memset (buffer, 0, size*sizeof(char));
AAsset_read (asset, buffer, size);
AAsset_close (asset);
hip_t ht = hip_decode_init ();
int count = hip_decode (ht, (unsigned char*)buffer, size, pcm_l, pcm_r);
free (buffer);
Print ("ConvertMp3toPCM: length:%ld,pcmcount=%d",length, count);
}
I used MACRO "HAVE_MPGLIB" to compile Lame in NDK. So I think it should work for decoding literally.

Answer 1

Yesterday I had the same problem. Is the same problem but using lame_enc.dll. I did not know how to resolve this 0 returned, this is the reason to this post.
Create a buffer to put mp3 data: unsigned char mp3Data[4096]
Create two buffers for pcm data, but bigger than mp3 one:
unsigned short[4096 * 100];
Open mp3 file and initialize hip.
Now, enter in a do while loop until read bytes are 0 (the end of file).
Inside the loop read 4096 bytes into mp3Data and call hip_decode with
hip_decode(ht, mp3Data, bytesRead, lpcm, rpcm);
You are right, it returns 0. It is asking you for more data.
You need to repeat the reading of 4096 bytes and the call to hip_decode until it returns a valid samples number.
Here is the important part of my program:
int total = 0;
int hecho = 0;
int leido = 0;
int lon = 0;
int x;
do
{
total = fread(mp3b, 1, MAXIMO, fich);
leido += total;
x = hip_decode(hgf, mp3b, total, izquierda, derecha);
if(x > 0)
{
int tamanio;
int y;
tamanio = 1.45 * x + 9200;
unsigned char * bu = (unsigned char *) malloc(tamanio);
y = lame_encode_buffer(lamglofla, izquierda, derecha, x, bu, tamanio);
fwrite(bu, 1, y, fichs);
free(bu);
}
}while(total > 0);
My program decodes a mp3 file and encodes the output into another mp3 file.
I expect that this could be useful.