我目前正在开发一款需要降低音乐速度的应用程序，我在线搜索，在android中唯一可行的选项是OpenSL ES。我从基础开始，所以我只是播放了一个音频文件但由于某种原因我无法改变节奏。我收到以下错误
04-04 15:32:51.950: W/libOpenSLES(12848): Leaving Object::GetInterface (SL_RESULT_FEATURE_UNSUPPORTED)
我已经检查过该功能是否受支持，文档是否也是如此，也许我的代码中有些错误？我从来没有使用过C ++，所以任何帮助都会受到赞赏。我的代码如下
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/* This is a JNI example where we use native methods to play sounds
* using OpenSL ES. See the corresponding Java source file located at:
*
* src/com/example/nativeaudio/NativeAudio/NativeAudio.java
*/
#include <assert.h>
#include <jni.h>
#include <string.h>
// for __android_log_print(ANDROID_LOG_INFO, "YourApp", "formatted message");
// #include <android/log.h>
// for native audio
#include <SLES/OpenSLES.h>
#include <SLES/OpenSLES_Android.h>
// for native asset manager
#include <sys/types.h>
#include <android/asset_manager.h>
#include <android/asset_manager_jni.h>
// pre-recorded sound clips, both are 8 kHz mono 16-bit signed little endian
static const char hello[] =
#include "hello_clip.h"
;
static const char android[] =
#include "android_clip.h"
;
// engine interfaces
static SLObjectItf engineObject = NULL;
static SLEngineItf engineEngine;
// output mix interfaces
static SLObjectItf outputMixObject = NULL;
static SLEnvironmentalReverbItf outputMixEnvironmentalReverb = NULL;
// aux effect on the output mix, used by the buffer queue player
static const SLEnvironmentalReverbSettings reverbSettings =
SL_I3DL2_ENVIRONMENT_PRESET_STONECORRIDOR;
// file descriptor player interfaces
static SLObjectItf fdPlayerObject = NULL;
static SLPlayItf fdPlayerPlay;
static SLSeekItf fdPlayerSeek;
static SLMuteSoloItf fdPlayerMuteSolo;
static SLVolumeItf fdPlayerVolume;
// synthesized sawtooth clip
#define SAWTOOTH_FRAMES 8000
static short sawtoothBuffer[SAWTOOTH_FRAMES];
// pointer and size of the next player buffer to enqueue, and number of remaining buffers
static short *nextBuffer;
static unsigned nextSize;
static int nextCount;
// playback rate (default 1x:1000)
static SLpermille playbackMinRate = 500;
static SLpermille playbackMaxRate = 2000;
static SLpermille playbackRateStepSize;
static SLPlaybackRateItf fdPlaybackRate;
// create the engine and output mix objects
void Java_com_example_nativeaudio_NativeAudio_createEngine(JNIEnv* env, jclass clazz)
{
SLresult result;
// create engine
result = slCreateEngine(&engineObject, 0, NULL, 0, NULL, NULL);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// realize the engine
result = (*engineObject)->Realize(engineObject, SL_BOOLEAN_FALSE);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// get the engine interface, which is needed in order to create other objects
result = (*engineObject)->GetInterface(engineObject, SL_IID_ENGINE, &engineEngine);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// create output mix, with environmental reverb specified as a non-required interface
const SLInterfaceID ids[1] = {SL_IID_ENVIRONMENTALREVERB};
const SLboolean req[1] = {SL_BOOLEAN_FALSE};
result = (*engineEngine)->CreateOutputMix(engineEngine, &outputMixObject, 1, ids, req);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// realize the output mix
result = (*outputMixObject)->Realize(outputMixObject, SL_BOOLEAN_FALSE);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// get the environmental reverb interface
// this could fail if the environmental reverb effect is not available,
// either because the feature is not present, excessive CPU load, or
// the required MODIFY_AUDIO_SETTINGS permission was not requested and granted
result = (*outputMixObject)->GetInterface(outputMixObject, SL_IID_ENVIRONMENTALREVERB,
&outputMixEnvironmentalReverb);
if (SL_RESULT_SUCCESS == result) {
result = (*outputMixEnvironmentalReverb)->SetEnvironmentalReverbProperties(
outputMixEnvironmentalReverb, &reverbSettings);
(void)result;
}
// ignore unsuccessful result codes for environmental reverb, as it is optional for this example
}
// expose the mute/solo APIs to Java for one of the 3 players
// expose the volume APIs to Java for one of the 3 players
// enable reverb on the buffer queue player
jboolean Java_com_example_nativeaudio_NativeAudio_enableReverb(JNIEnv* env, jclass clazz,
jboolean enabled)
{
SLresult result;
// we might not have been able to add environmental reverb to the output mix
if (NULL == outputMixEnvironmentalReverb) {
return JNI_FALSE;
}
return JNI_TRUE;
}
// create asset audio player
jboolean Java_com_example_nativeaudio_NativeAudio_createAssetAudioPlayer(JNIEnv* env, jclass clazz,
jobject assetManager, jstring filename)
{
SLresult result;
// convert Java string to UTF-8
const char *utf8 = (*env)->GetStringUTFChars(env, filename, NULL);
assert(NULL != utf8);
// use asset manager to open asset by filename
AAssetManager* mgr = AAssetManager_fromJava(env, assetManager);
assert(NULL != mgr);
AAsset* asset = AAssetManager_open(mgr, utf8, AASSET_MODE_UNKNOWN);
// release the Java string and UTF-8
(*env)->ReleaseStringUTFChars(env, filename, utf8);
// the asset might not be found
if (NULL == asset) {
return JNI_FALSE;
}
// open asset as file descriptor
off_t start, length;
int fd = AAsset_openFileDescriptor(asset, &start, &length);
assert(0 <= fd);
AAsset_close(asset);
// configure audio source
SLDataLocator_AndroidFD loc_fd = {SL_DATALOCATOR_ANDROIDFD, fd, start, length};
SLDataFormat_MIME format_mime = {SL_DATAFORMAT_MIME, NULL, SL_CONTAINERTYPE_UNSPECIFIED};
SLDataSource audioSrc = {&loc_fd, &format_mime};
// configure audio sink
SLDataLocator_OutputMix loc_outmix = {SL_DATALOCATOR_OUTPUTMIX, outputMixObject};
SLDataSink audioSnk = {&loc_outmix, NULL};
// create audio player
const SLInterfaceID ids[3] = {SL_IID_SEEK, SL_IID_MUTESOLO, SL_IID_VOLUME};
const SLboolean req[3] = {SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE};
result = (*engineEngine)->CreateAudioPlayer(engineEngine, &fdPlayerObject, &audioSrc, &audioSnk,
3, ids, req);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// realize the player
result = (*fdPlayerObject)->Realize(fdPlayerObject, SL_BOOLEAN_FALSE);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// get the play interface
result = (*fdPlayerObject)->GetInterface(fdPlayerObject, SL_IID_PLAY, &fdPlayerPlay);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// get the seek interface
result = (*fdPlayerObject)->GetInterface(fdPlayerObject, SL_IID_SEEK, &fdPlayerSeek);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// get the mute/solo interface
result = (*fdPlayerObject)->GetInterface(fdPlayerObject, SL_IID_MUTESOLO, &fdPlayerMuteSolo);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// get the volume interface
result = (*fdPlayerObject)->GetInterface(fdPlayerObject, SL_IID_VOLUME, &fdPlayerVolume);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// enable whole file looping
result = (*fdPlayerSeek)->SetLoop(fdPlayerSeek, SL_BOOLEAN_TRUE, 0, SL_TIME_UNKNOWN);
assert(SL_RESULT_SUCCESS == result);
(void)result;
// get playback rate interface
result = (*fdPlayerObject)->GetInterface(fdPlayerObject,
SL_IID_PLAYBACKRATE, &fdPlaybackRate);
assert(SL_RESULT_SUCCESS == result);
SLuint32 capa;
result = (*fdPlaybackRate)->GetRateRange(fdPlaybackRate, 0,
&playbackMinRate, &playbackMaxRate, &playbackRateStepSize, &capa);
assert(SL_RESULT_SUCCESS == result);
result = (*fdPlaybackRate)->SetPropertyConstraints(fdPlaybackRate,
SL_RATEPROP_PITCHCORAUDIO);
if (SL_RESULT_PARAMETER_INVALID == result) {
// LOGD("Parameter Invalid");
}
if (SL_RESULT_FEATURE_UNSUPPORTED == result) {
// LOGD("Feature Unsupported");
}
if (SL_RESULT_SUCCESS == result) {
assert(SL_RESULT_SUCCESS == result);
// LOGD("Success");
}
// result = (*fdPlaybackRate)->SetRate(fdPlaybackRate, playbackMaxRate);
// assert(SL_RESULT_SUCCESS == result);
SLpermille SLrate;
result = (*fdPlaybackRate)->GetRate(fdPlaybackRate, &SLrate);
assert(SL_RESULT_SUCCESS == result);
// enable whole file looping
result = (*fdPlayerSeek)->SetLoop(fdPlayerSeek, SL_BOOLEAN_FALSE, 0, SL_TIME_UNKNOWN);
assert(SL_RESULT_SUCCESS == result);
(void)result;
return JNI_TRUE;
}
/*JNIEXPORT void Java_com_example_stackoverflowcode_NativeAudio_setRate(JNIEnv* env, jclass clazz, jint rate) {
result = (*fdPlayerRate)->SetRate(fdPlayerRate, playbackMaxRate);
assert(SL_RESULT_SUCCESS == result);
}
*/
JNIEXPORT void Java_com_example_stackoverflowcode_NativeAudio_setRate(
JNIEnv* env, jclass clazz, jint rate) {
if (NULL != fdPlaybackRate) {
SLresult result;
result = (*fdPlaybackRate)->SetRate(fdPlaybackRate, rate);
assert(SL_RESULT_SUCCESS == result);
}
}
// set the playing state for the asset audio player
void Java_com_example_nativeaudio_NativeAudio_setPlayingAssetAudioPlayer(JNIEnv* env,
jclass clazz, jboolean isPlaying)
{
SLresult result;
// make sure the asset audio player was created
if (NULL != fdPlayerPlay) {
// set the player's state
result = (*fdPlayerPlay)->SetPlayState(fdPlayerPlay, isPlaying ?
SL_PLAYSTATE_PLAYING : SL_PLAYSTATE_PAUSED);
assert(SL_RESULT_SUCCESS == result);
(void)result;
}
}
// shut down the native audio system
void Java_com_example_nativeaudio_NativeAudio_shutdown(JNIEnv* env, jclass clazz)
{
// destroy file descriptor audio player object, and invalidate all associated interfaces
if (fdPlayerObject != NULL) {
(*fdPlayerObject)->Destroy(fdPlayerObject);
fdPlayerObject = NULL;
fdPlayerPlay = NULL;
fdPlayerSeek = NULL;
fdPlayerMuteSolo = NULL;
fdPlayerVolume = NULL;
}
// destroy output mix object, and invalidate all associated interfaces
if (outputMixObject != NULL) {
(*outputMixObject)->Destroy(outputMixObject);
outputMixObject = NULL;
outputMixEnvironmentalReverb = NULL;
}
// destroy engine object, and invalidate all associated interfaces
if (engineObject != NULL) {
(*engineObject)->Destroy(engineObject);
engineObject = NULL;
engineEngine = NULL;
}
}
非常感谢任何帮助。感谢
答案 0 :(得分：1)
我想在这里再说一些步骤：
1）获取DynamicInterfaceManagementItf
2）通过DynamicInterfaceManagementItf添加PlayBackRateItf
3）获取对象的界面
// get dynamic interface
result = (*fdPlayerObject)->GetInterface(fdPlayerObject,
SL_IID_DYNAMICINTERFACEMANAGEMENT,
(void*) &dynamicInterfaceManagementItf);
CheckErr(result);
// add playback rate itf
result = (*dynamicInterfaceManagementItf)->AddInterface(
dynamicInterfaceManagementItf, SL_IID_PLAYBACKRATE,
SL_BOOLEAN_FALSE);
CheckErr(result);
// get the playbackrate interface
result = (*fdPlayerObject)->GetInterface(fdPlayerObject,
SL_IID_PLAYBACKRATE, &fdPlaybackRateItf);
CheckErr(result);
希望它可以帮到你