Playing PCM WAVE sound from memory with OpenSL on Android

问题

I'm trying to set up OpenSL AudioPlayer to use memory I've allocated to playback a wav file. I want to do this so I can have multiple AudioPlayers that share the same data and conserve memory.

I've tried to give openSL the entire file and tell it that it is a WAVE with format_mime

 SLDataLocator_Address loc_fd = {SL_DATALOCATOR_ADDRESS, data, size};
SLDataFormat_MIME format_mime = { SL_DATAFORMAT_MIME, (SLchar*)"audio/x-wav",SL_CONTAINERTYPE_WAV};
SLDataSource audioSrc = { &loc_fd, &format_mime };
// configure audio sink
SLDataLocator_OutputMix loc_outmix = { SL_DATALOCATOR_OUTPUTMIX,outputMixObject };
SLDataSink audioSnk = { &loc_outmix, 0 };
// create audio player
const SLInterfaceID ids[2] = { SL_IID_SEEK, SL_IID_PLAYBACKRATE };
const SLboolean req[2] = { SL_BOOLEAN_FALSE, SL_BOOLEAN_FALSE };
result = (*engineEngine)->CreateAudioPlayer(engineEngine,&uriPlayerObject[cntSOUND],&audioSrc, &audioSnk, 0, ids, req);

and I have parsed the WAVE data myself and loaded format_pcm

SLDataFormat_PCM format_pcm;
format_pcm.formatType = SL_DATAFORMAT_PCM;
char* wavParser = isWAVE(data);
if(wavParser == NULL)
{
    Log("NOT A WAVE!");
    return -1;
}
char* fmtChunk = getChunk("fmt ", data, size);
parsefmtChunk(fmtChunk, &format_pcm);
char* dataChunk = getChunk("data",data, size);
dataChunk += 4;
unsigned int dataSize = *((unsigned int*)dataChunk);
dataChunk += 4;
format_pcm.channelMask = 0;
format_pcm.containerSize = 16;
format_pcm.endianness = SL_BYTEORDER_LITTLEENDIAN;
loc_fd.pAddress = dataChunk;
loc_fd.length = dataSize;

The parsefmtChunk function is

void parsefmtChunk(char* fmtchunk, SLDataFormat_PCM* pcm)
{
char* data = fmtchunk + 8;
unsigned short audioFormat = *((unsigned short*)data);
if(audioFormat != 1)
{
    Log("Not PCM!");
    Log("Reached Line:%d in File %s", __LINE__, __FILE__);
    return;
}
data += 2;
pcm->numChannels = *((unsigned short*)data);
data += 2;
pcm->samplesPerSec = *((unsigned int*)data);
data += 4;
//Byte Rate
data += 4;
//Block Align
data += 2;
//BitsPerSample
pcm->bitsPerSample = *((unsigned short*)data);

(Are Byte Rate and Block Align supposed to be used somehow to fill out the pcm struct?)

but whenever I create the audioplayer I get SL_RESULT_CONTENT_UNSUPPORTED

This is what I log from my parsefmt function Channels:2 samplesPerSec:44100 bitsPerSample:16

回答1:

from android-ndk-r8b/docs/opensles/index.html

PCM data format

The PCM data format can be used with buffer queues only.

So SLDataFormat_PCM CANNOT be used with SLDataLocator_Address like I assumed.

I can do what I want with a Buffer Queue instead by using just one big queue like so

bufferqueueitf->Enqueue(bufferqueueitf,dataChunk,dataSize);

回答2:

Have you tried this?

SLDataFormat_MIME format_mime = {SL_DATAFORMAT_MIME, NULL, SL_CONTAINERTYPE_UNSPECIFIED};

The Android implementation of OpenSL ES isn't totally compliant and http://mobilepearls.com/labs/native-android-api/ndk/docs/opensles/ recommends the following:

The Android implementation of OpenSL ES requires that mimeType be initialized to either NULL or a valid UTF-8 string, and that containerType be initialized to a valid value. In the absence of other considerations, such as portability to other implementations, or content format which cannot be identified by header, we recommend that you set the mimeType to NULL and containerType to SL_CONTAINERTYPE_UNSPECIFIED.

Also, make sure you're giving it a valid URI.

来源：https://stackoverflow.com/questions/19062499/playing-pcm-wave-sound-from-memory-with-opensl-on-android

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android

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