Silk编解码是Skype向第三方开发人员和硬件制造商提供免版税认证(RF)的Silk宽带音频编码器。Skype已将其开源，可以访问
http://developer.skype.com/silk
获取最新动向。SILK Codec是一个语音和音频编解码算法, 对于音频带宽、网络带宽和算法复杂度都具有很好的弹性。支持4种采样率：8KHz、12KHz、16KHz、24KHz；三种复杂度：低、中、高。编码码率在 6~40kbps（不同采样率具有不同的码率范围）以及还支持VAD、DTX、FEC等模块，感觉还是比较全面。最重要的一点是提供了定点C代码，非常有利于向ARM、DSP移植和优化。这一篇主要参考了pjsip中的silk实现。
1、获取silk源码（http://developer.skype.com/silk）
2、创建新的android工程，并创建jni文件夹。
3、将silk源码拷贝到jni目录
4、在jni目录下新增Android.mk文件，编辑内容如下：
LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) SILK := silk LOCAL_MODULE := silkcommon LOCAL_SRC_FILES := $(SILK)/src/SKP_Silk_A2NLSF.c \ $(SILK)/src/SKP_Silk_CNG.c \ $(SILK)/src/SKP_Silk_HP_variable_cutoff_FIX.c \ $(SILK)/src/SKP_Silk_LBRR_reset.c \ $(SILK)/src/SKP_Silk_LPC_inv_pred_gain.c \ $(SILK)/src/SKP_Silk_LPC_stabilize.c \ $(SILK)/src/SKP_Silk_LPC_synthesis_filter.c \ $(SILK)/src/SKP_Silk_LPC_synthesis_order16.c \ $(SILK)/src/SKP_Silk_LP_variable_cutoff.c \ $(SILK)/src/SKP_Silk_LSF_cos_table.c \ $(SILK)/src/SKP_Silk_LTP_analysis_filter_FIX.c \ $(SILK)/src/SKP_Silk_LTP_scale_ctrl_FIX.c \ $(SILK)/src/SKP_Silk_MA.c \ $(SILK)/src/SKP_Silk_NLSF2A.c \ $(SILK)/src/SKP_Silk_NLSF2A_stable.c \ $(SILK)/src/SKP_Silk_NLSF_MSVQ_decode.c \ $(SILK)/src/SKP_Silk_NLSF_MSVQ_encode_FIX.c \ $(SILK)/src/SKP_Silk_NLSF_VQ_rate_distortion_FIX.c \ $(SILK)/src/SKP_Silk_NLSF_VQ_sum_error_FIX.c \ $(SILK)/src/SKP_Silk_NLSF_VQ_weights_laroia.c \ $(SILK)/src/SKP_Silk_NLSF_stabilize.c \ $(SILK)/src/SKP_Silk_NSQ.c \ $(SILK)/src/SKP_Silk_NSQ_del_dec.c \ $(SILK)/src/SKP_Silk_PLC.c \ $(SILK)/src/SKP_Silk_VAD.c \ $(SILK)/src/SKP_Silk_VQ_nearest_neighbor_FIX.c \ $(SILK)/src/SKP_Silk_allpass_int.c \ $(SILK)/src/SKP_Silk_ana_filt_bank_1.c \ $(SILK)/src/SKP_Silk_apply_sine_window.c \ $(SILK)/src/SKP_Silk_array_maxabs.c \ $(SILK)/src/SKP_Silk_autocorr.c \ $(SILK)/src/SKP_Silk_biquad.c \ $(SILK)/src/SKP_Silk_biquad_alt.c \ $(SILK)/src/SKP_Silk_burg_modified.c \ $(SILK)/src/SKP_Silk_bwexpander.c \ $(SILK)/src/SKP_Silk_bwexpander_32.c \ $(SILK)/src/SKP_Silk_code_signs.c \ $(SILK)/src/SKP_Silk_control_codec_FIX.c \ $(SILK)/src/SKP_Silk_corrMatrix_FIX.c \ $(SILK)/src/SKP_Silk_create_init_destroy.c \ $(SILK)/src/SKP_Silk_dec_API.c \ $(SILK)/src/SKP_Silk_decode_core.c \ $(SILK)/src/SKP_Silk_decode_frame.c \ $(SILK)/src/SKP_Silk_decode_indices_v4.c \ $(SILK)/src/SKP_Silk_decode_parameters.c \ $(SILK)/src/SKP_Silk_decode_parameters_v4.c \ $(SILK)/src/SKP_Silk_decode_pulses.c \ $(SILK)/src/SKP_Silk_decoder_set_fs.c \ $(SILK)/src/SKP_Silk_detect_SWB_input.c \ $(SILK)/src/SKP_Silk_enc_API.c \ $(SILK)/src/SKP_Silk_encode_frame_FIX.c \ $(SILK)/src/SKP_Silk_encode_parameters.c \ $(SILK)/src/SKP_Silk_encode_parameters_v4.c \ $(SILK)/src/SKP_Silk_encode_pulses.c \ $(SILK)/src/SKP_Silk_find_LPC_FIX.c \ $(SILK)/src/SKP_Silk_find_LTP_FIX.c \ $(SILK)/src/SKP_Silk_find_pitch_lags_FIX.c \ $(SILK)/src/SKP_Silk_find_pred_coefs_FIX.c \ $(SILK)/src/SKP_Silk_gain_quant.c \ $(SILK)/src/SKP_Silk_init_encoder_FIX.c \ $(SILK)/src/SKP_Silk_inner_prod_aligned.c \ $(SILK)/src/SKP_Silk_interpolate.c \ $(SILK)/src/SKP_Silk_k2a.c \ $(SILK)/src/SKP_Silk_k2a_Q16.c \ $(SILK)/src/SKP_Silk_lin2log.c \ $(SILK)/src/SKP_Silk_log2lin.c \ $(SILK)/src/SKP_Silk_lowpass_int.c \ $(SILK)/src/SKP_Silk_lowpass_short.c \ $(SILK)/src/SKP_Silk_noise_shape_analysis_FIX.c \ $(SILK)/src/SKP_Silk_pitch_analysis_core.c \ $(SILK)/src/SKP_Silk_pitch_est_tables.c \ $(SILK)/src/SKP_Silk_prefilter_FIX.c \ $(SILK)/src/SKP_Silk_process_NLSFs_FIX.c \ $(SILK)/src/SKP_Silk_process_gains_FIX.c \ $(SILK)/src/SKP_Silk_pulses_to_bytes.c \ $(SILK)/src/SKP_Silk_quant_LTP_gains_FIX.c \ $(SILK)/src/SKP_Silk_range_coder.c \ $(SILK)/src/SKP_Silk_regularize_correlations_FIX.c \ $(SILK)/src/SKP_Silk_resample_1_2.c \ $(SILK)/src/SKP_Silk_resample_1_2_coarse.c \ $(SILK)/src/SKP_Silk_resample_1_2_coarsest.c \ $(SILK)/src/SKP_Silk_resample_1_3.c \ $(SILK)/src/SKP_Silk_resample_2_1_coarse.c \ $(SILK)/src/SKP_Silk_resample_2_3.c \ $(SILK)/src/SKP_Silk_resample_2_3_coarse.c \ $(SILK)/src/SKP_Silk_resample_2_3_coarsest.c \ $(SILK)/src/SKP_Silk_resample_2_3_rom.c \ $(SILK)/src/SKP_Silk_resample_3_1.c \ $(SILK)/src/SKP_Silk_resample_3_2.c \ $(SILK)/src/SKP_Silk_resample_3_2_rom.c \ $(SILK)/src/SKP_Silk_resample_3_4.c \ $(SILK)/src/SKP_Silk_resample_4_3.c \ $(SILK)/src/SKP_Silk_residual_energy16_FIX.c \ $(SILK)/src/SKP_Silk_residual_energy_FIX.c \ $(SILK)/src/SKP_Silk_scale_copy_vector16.c \ $(SILK)/src/SKP_Silk_scale_vector.c \ $(SILK)/src/SKP_Silk_schur.c \ $(SILK)/src/SKP_Silk_schur64.c \ $(SILK)/src/SKP_Silk_shell_coder.c \ $(SILK)/src/SKP_Silk_sigm_Q15.c \ $(SILK)/src/SKP_Silk_solve_LS_FIX.c \ $(SILK)/src/SKP_Silk_sort.c \ $(SILK)/src/SKP_Silk_sum_sqr_shift.c \ $(SILK)/src/SKP_Silk_tables_LTP.c \ $(SILK)/src/SKP_Silk_tables_NLSF_CB0_10.c \ $(SILK)/src/SKP_Silk_tables_NLSF_CB0_16.c \ $(SILK)/src/SKP_Silk_tables_NLSF_CB1_10.c \ $(SILK)/src/SKP_Silk_tables_NLSF_CB1_16.c \ $(SILK)/src/SKP_Silk_tables_gain.c \ $(SILK)/src/SKP_Silk_tables_other.c \ $(SILK)/src/SKP_Silk_tables_pitch_lag.c \ $(SILK)/src/SKP_Silk_tables_pulses_per_block.c \ $(SILK)/src/SKP_Silk_tables_sign.c \ $(SILK)/src/SKP_Silk_tables_type_offset.c LOCAL_ARM_MODE := arm LOCAL_CFLAGS = -O3 LOCAL_LDLIBS := -L$(SYSROOT)/usr/lib -llog LOCAL_C_INCLUDES += $(LOCAL_PATH)/$(SILK)/src $(LOCAL_PATH)/$(SILK)/interface include $(BUILD_STATIC_LIBRARY) include $(CLEAR_VARS) LOCAL_MODULE := silk8_jni LOCAL_SRC_FILES := silk8_jni.cpp LOCAL_C_INCLUDES += $(LOCAL_PATH)/$(SILK)/src $(LOCAL_PATH)/$(SILK)/interface LOCAL_CFLAGS = -O3 LOCAL_STATIC_LIBRARIES := silkcommon LOCAL_ARM_MODE := arm LOCAL_LDLIBS := -L$(SYSROOT)/usr/lib -llog include $(BUILD_SHARED_LIBRARY) include $(CLEAR_VARS) LOCAL_MODULE := silk16_jni LOCAL_SRC_FILES := silk16_jni.cpp LOCAL_C_INCLUDES += $(LOCAL_PATH)/$(SILK)/src $(LOCAL_PATH)/$(SILK)/interface LOCAL_CFLAGS = -O3 LOCAL_STATIC_LIBRARIES := silkcommon LOCAL_ARM_MODE := arm LOCAL_LDLIBS := -L$(SYSROOT)/usr/lib -llog include $(BUILD_SHARED_LIBRARY) include $(CLEAR_VARS) LOCAL_MODULE := silk24_jni LOCAL_SRC_FILES := silk24_jni.cpp LOCAL_C_INCLUDES += $(LOCAL_PATH)/$(SILK)/src $(LOCAL_PATH)/$(SILK)/interface LOCAL_CFLAGS = -O3 LOCAL_STATIC_LIBRARIES := silkcommon LOCAL_ARM_MODE := arm LOCAL_LDLIBS := -L$(SYSROOT)/usr/lib -llog include $(BUILD_SHARED_LIBRARY)
5、创建JNI包装类silk8_jni.cpp、silk16_jni.cpp、silk24_jni.cpp，用来调用Silk中的C代码函数，编辑内容如下
silk8_jni.cpp:
#include <jni.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <math.h> /* Define codec specific settings */ #define MAX_BYTES_ENC_PER_FRAME 250 // Equals peak bitrate of 100 kbps #define MAX_BYTES_DEC_PER_FRAME 1024 #define MAX_INPUT_FRAMES 5 #define MAX_LBRR_DELAY 2 #define MAX_FRAME_LENGTH 480 #define MAX_FRAME 160 #include <android/log.h> #define LOG_TAG "silk" // text for log tag #include "SKP_Silk_SDK_API.h" #include "SKP_Silk_SigProc_FIX.h" #undef DEBUG_SILK8 // the header length of the RTP frame (must skip when en/decoding) #define RTP_HDR_SIZE 12 static int codec_open = 0; static JavaVM *gJavaVM; const char *kInterfacePath = "org/sipdroid/pjlib/silk8"; /* encoder parameters */ SKP_int32 encSizeBytes; void *psEnc; /* default settings */ SKP_int fs_kHz = 8; SKP_int targetRate_bps = 20000; SKP_int packetSize_ms = 20; SKP_int frameSizeReadFromFile_ms = 20; SKP_int packetLoss_perc = 0, smplsSinceLastPacket; SKP_int INBandFec_enabled = 0, DTX_enabled = 0, quiet = 0; SKP_SILK_SDK_EncControlStruct encControl; // Struct for input to encoder /* decoder parameters */ jbyte payloadToDec[ MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES * ( MAX_LBRR_DELAY + 1 ) ]; jshort out[ ( MAX_FRAME_LENGTH << 1 ) * MAX_INPUT_FRAMES ], *outPtr; SKP_int32 decSizeBytes; void *psDec; SKP_SILK_SDK_DecControlStruct DecControl; extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK8_open (JNIEnv *env, jobject obj, jint compression) { int ret; if (codec_open++ != 0) return (jint)0; /* Set the samplingrate that is requested for the output */ DecControl.sampleRate = 8000; /* Create decoder */ ret = SKP_Silk_SDK_Get_Decoder_Size( &decSizeBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_Get_Decoder_Size returned %d", ret ); } #ifdef DEBUG_SILK8 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "### INIT Decoder decSizeBytes = %d\n", decSizeBytes); #endif psDec = malloc( decSizeBytes ); /* Reset decoder */ ret = SKP_Silk_SDK_InitDecoder( psDec ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_InitDecoder returned %d", ret ); } /* Create Encoder */ ret = SKP_Silk_SDK_Get_Encoder_Size( &encSizeBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_Get_Encoder_Size returned %d", ret ); } #ifdef DEBUG_SILK8 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "### INIT Encoder encSizeBytes = %d\n", encSizeBytes); #endif psEnc = malloc( encSizeBytes ); /* Reset Encoder */ ret = SKP_Silk_SDK_InitEncoder( psEnc, &encControl ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_InitEncoder returned %d", ret ); } /* Set Encoder parameters */ encControl.sampleRate = fs_kHz * 1000; encControl.packetSize = packetSize_ms * fs_kHz; encControl.packetLossPercentage = packetLoss_perc; encControl.useInBandFEC = INBandFec_enabled; encControl.useDTX = DTX_enabled; encControl.complexity = compression; encControl.bitRate = targetRate_bps; return (jint)0; } void Print_Decode_Error_Msg(int errcode) { switch (errcode) { case SKP_SILK_DEC_WRONG_SAMPLING_FREQUENCY: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nOutput sampling frequency lower than internal decoded sampling frequency\n", errcode); break; case SKP_SILK_DEC_PAYLOAD_TOO_LARGE: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPayload size exceeded the maximum allowed 1024 bytes\n", errcode); break; case SKP_SILK_DEC_PAYLOAD_ERROR: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPayload has bit errors\n", errcode); break; } } void Print_Encode_Error_Msg(int errcode) { switch (errcode) { case SKP_SILK_ENC_INPUT_INVALID_NO_OF_SAMPLES: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInput length is not a multiplum of 10 ms, or length is longer than the packet length\n", errcode); break; case SKP_SILK_ENC_FS_NOT_SUPPORTED: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nSampling frequency not 8000, 12000, 16000 or 24000 Hertz \n", errcode); break; case SKP_SILK_ENC_PACKET_SIZE_NOT_SUPPORTED: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPacket size not 20, 40, 60, 80 or 100 ms\n", errcode); break; case SKP_SILK_ENC_PAYLOAD_BUF_TOO_SHORT: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nAllocated payload buffer too short \n", errcode); break; case SKP_SILK_ENC_WRONG_LOSS_RATE: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nLoss rate not between 0 and 100 percent\n", errcode); break; case SKP_SILK_ENC_WRONG_COMPLEXITY_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nComplexity setting not valid, use 0, 1 or 2\n", errcode); break; case SKP_SILK_ENC_WRONG_INBAND_FEC_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInband FEC setting not valid, use 0 or 1\n", errcode); break; case SKP_SILK_ENC_WRONG_DTX_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nDTX setting not valid, use 0 or 1\n", errcode); break; case SKP_SILK_ENC_INTERNAL_ERROR: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInternal encoder error\n", errcode); break; } } extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK8_encode (JNIEnv *env, jobject obj, jshortArray lin, jint offset, jbyteArray encoded, jint size) { jbyte enc_payload[ MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES ]; jshort in[ MAX_FRAME_LENGTH * MAX_INPUT_FRAMES ]; int ret,i,frsz=MAX_FRAME; SKP_int16 nBytes; unsigned int lin_pos = 0; if (!codec_open) return 0; #ifdef DEBUG_SILK8 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding frame size: %d\toffset: %d\n", size, offset); #endif for (i = 0; i < size; i+=MAX_FRAME) { #ifdef DEBUG_SILK8 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding frame size: %d\toffset: %d i: %d\n", size, offset, i); #endif env->GetShortArrayRegion(lin, offset + i,frsz, in); /* max payload size */ nBytes = MAX_BYTES_ENC_PER_FRAME * MAX_INPUT_FRAMES; ret = SKP_Silk_SDK_Encode( psEnc, &encControl, in, (SKP_int16)frsz, (SKP_uint8 *)enc_payload, &nBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!! SKP_Silk_Encode returned: %d\n", ret); Print_Encode_Error_Msg(ret); break; } #ifdef DEBUG_SILK8 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "Enocded nBytes: %d\n", nBytes); #endif /* Write payload */ env->SetByteArrayRegion(encoded, RTP_HDR_SIZE+ lin_pos, nBytes, enc_payload); lin_pos += nBytes; } #ifdef DEBUG_SILK8 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding **END** frame size: %d\toffset: %d i: %d lin_pos: %d\n", size, offset, i, lin_pos); #endif return (jint)lin_pos; } extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK8_decode (JNIEnv *env, jobject obj, jbyteArray encoded, jshortArray lin, jint size) { jbyte buffer [MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES * ( MAX_LBRR_DELAY + 1 ) ]; jshort output_buffer[( MAX_FRAME_LENGTH << 1 ) * MAX_INPUT_FRAMES ]; // SKP_int16 *outPtr; int ret; SKP_int16 len; // int tot_len,frames; if (!codec_open) return 0; #ifdef DEBUG_SILK8 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "##### BEGIN DECODE ******** decoding frame size: %d\n", size); #endif env->GetByteArrayRegion(encoded, RTP_HDR_SIZE, size, buffer); // outPtr = output_buffer; // tot_len = 0; // frames = 0; // do { ret = SKP_Silk_SDK_Decode( psDec, &DecControl, 0,(SKP_uint8 *) buffer, size, output_buffer,&len ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!! SKP_Silk_SDK_Decode returned: %d\n", ret); Print_Decode_Error_Msg(ret); } #ifdef DEBUG_SILK8 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "##### DECODED length: %d\n\t Frame #: %d", len); #endif // frames++; // outPtr += len; // tot_len += len; // } while( DecControl.moreInternalDecoderFrames ); env->SetShortArrayRegion(lin, 0, len,output_buffer); return (jint)len; } extern "C" JNIEXPORT void JNICALL Java_com_trunkbow_silk_SILK8_close (JNIEnv *env, jobject obj) { if (--codec_open != 0) return; /* Free decoder */ free( psDec ); /* Free Encoder */ free( psEnc ); }
silk_16.cpp:
#include <jni.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <math.h> /* Define codec specific settings */ #define MAX_BYTES_ENC_PER_FRAME 250 // Equals peak bitrate of 100 kbps #define MAX_BYTES_DEC_PER_FRAME 1024 #define MAX_INPUT_FRAMES 5 #define MAX_LBRR_DELAY 2 #define MAX_FRAME_LENGTH 480 #define MAX_FRAME 320 #include <android/log.h> #define LOG_TAG "silk" // text for log tag #include "SKP_Silk_SDK_API.h" #include "SKP_Silk_SigProc_FIX.h" #undef DEBUG_SILK16 // the header length of the RTP frame (must skip when en/decoding) #define RTP_HDR_SIZE 12 static int codec_open = 0; static JavaVM *gJavaVM; const char *kInterfacePath = "org/sipdroid/pjlib/silk16"; /* encoder parameters */ SKP_int32 encSizeBytes; void *psEnc; /* default settings */ SKP_int fs_kHz = 16; SKP_int targetRate_bps = 20000; SKP_int packetSize_ms = 20; SKP_int frameSizeReadFromFile_ms = 20; SKP_int packetLoss_perc = 0, smplsSinceLastPacket; SKP_int INBandFec_enabled = 0, DTX_enabled = 0, quiet = 0; SKP_SILK_SDK_EncControlStruct encControl; // Struct for input to encoder /* decoder parameters */ jbyte payloadToDec[ MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES * ( MAX_LBRR_DELAY + 1 ) ]; jshort out[ ( MAX_FRAME_LENGTH << 1 ) * MAX_INPUT_FRAMES ], *outPtr; SKP_int32 decSizeBytes; void *psDec; SKP_SILK_SDK_DecControlStruct DecControl; extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK16_open (JNIEnv *env, jobject obj, jint compression) { int ret; if (codec_open++ != 0) return (jint)0; /* Set the samplingrate that is requested for the output */ DecControl.sampleRate = 16000; /* Create decoder */ ret = SKP_Silk_SDK_Get_Decoder_Size( &decSizeBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_Get_Decoder_Size returned %d", ret ); } #ifdef DEBUG_SILK16 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "### INIT Decoder decSizeBytes = %d\n", decSizeBytes); #endif psDec = malloc( decSizeBytes ); /* Reset decoder */ ret = SKP_Silk_SDK_InitDecoder( psDec ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_InitDecoder returned %d", ret ); } /* Create Encoder */ ret = SKP_Silk_SDK_Get_Encoder_Size( &encSizeBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_Get_Encoder_Size returned %d", ret ); } #ifdef DEBUG_SILK16 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "### INIT Encoder encSizeBytes = %d\n", encSizeBytes); #endif psEnc = malloc( encSizeBytes ); /* Reset Encoder */ ret = SKP_Silk_SDK_InitEncoder( psEnc, &encControl ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_InitEncoder returned %d", ret ); } /* Set Encoder parameters */ encControl.sampleRate = fs_kHz * 1000; encControl.packetSize = packetSize_ms * fs_kHz; encControl.packetLossPercentage = packetLoss_perc; encControl.useInBandFEC = INBandFec_enabled; encControl.useDTX = DTX_enabled; encControl.complexity = compression; encControl.bitRate = targetRate_bps; return (jint)0; } void Print_Decode_Error_Msg(int errcode) { switch (errcode) { case SKP_SILK_DEC_WRONG_SAMPLING_FREQUENCY: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nOutput sampling frequency lower than internal decoded sampling frequency\n", errcode); break; case SKP_SILK_DEC_PAYLOAD_TOO_LARGE: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPayload size exceeded the maximum allowed 1024 bytes\n", errcode); break; case SKP_SILK_DEC_PAYLOAD_ERROR: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPayload has bit errors\n", errcode); break; } } void Print_Encode_Error_Msg(int errcode) { switch (errcode) { case SKP_SILK_ENC_INPUT_INVALID_NO_OF_SAMPLES: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInput length is not a multiplum of 10 ms, or length is longer than the packet length\n", errcode); break; case SKP_SILK_ENC_FS_NOT_SUPPORTED: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nSampling frequency not 8000, 12000, 16000 or 24000 Hertz \n", errcode); break; case SKP_SILK_ENC_PACKET_SIZE_NOT_SUPPORTED: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPacket size not 20, 40, 60, 80 or 100 ms\n", errcode); break; case SKP_SILK_ENC_PAYLOAD_BUF_TOO_SHORT: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nAllocated payload buffer too short \n", errcode); break; case SKP_SILK_ENC_WRONG_LOSS_RATE: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nLoss rate not between 0 and 100 percent\n", errcode); break; case SKP_SILK_ENC_WRONG_COMPLEXITY_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nComplexity setting not valid, use 0, 1 or 2\n", errcode); break; case SKP_SILK_ENC_WRONG_INBAND_FEC_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInband FEC setting not valid, use 0 or 1\n", errcode); break; case SKP_SILK_ENC_WRONG_DTX_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nDTX setting not valid, use 0 or 1\n", errcode); break; case SKP_SILK_ENC_INTERNAL_ERROR: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInternal encoder error\n", errcode); break; } } extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK16_encode (JNIEnv *env, jobject obj, jshortArray lin, jint offset, jbyteArray encoded, jint size) { jbyte enc_payload[ MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES ]; jshort in[ MAX_FRAME_LENGTH * MAX_INPUT_FRAMES ]; int ret,i,frsz=MAX_FRAME; SKP_int16 nBytes; unsigned int lin_pos = 0; if (!codec_open) return 0; #ifdef DEBUG_SILK16 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding frame size: %d\toffset: %d\n", size, offset); #endif for (i = 0; i < size; i+=MAX_FRAME) { #ifdef DEBUG_SILK16 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding frame size: %d\toffset: %d i: %d\n", size, offset, i); #endif env->GetShortArrayRegion(lin, offset + i,frsz, in); /* max payload size */ nBytes = MAX_BYTES_ENC_PER_FRAME * MAX_INPUT_FRAMES; ret = SKP_Silk_SDK_Encode( psEnc, &encControl, in, (SKP_int16)frsz, (SKP_uint8 *)enc_payload, &nBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!! SKP_Silk_Encode returned: %d\n", ret); Print_Encode_Error_Msg(ret); break; } #ifdef DEBUG_SILK16 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "Enocded nBytes: %d\n", nBytes); #endif /* Write payload */ env->SetByteArrayRegion(encoded, RTP_HDR_SIZE+ lin_pos, nBytes, enc_payload); lin_pos += nBytes; } #ifdef DEBUG_SILK16 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding **END** frame size: %d\toffset: %d i: %d lin_pos: %d\n", size, offset, i, lin_pos); #endif return (jint)lin_pos; } extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK16_decode (JNIEnv *env, jobject obj, jbyteArray encoded, jshortArray lin, jint size) { jbyte buffer [MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES * ( MAX_LBRR_DELAY + 1 ) ]; jshort output_buffer[( MAX_FRAME_LENGTH << 1 ) * MAX_INPUT_FRAMES ]; // SKP_int16 *outPtr; int ret; SKP_int16 len; // int tot_len,frames; if (!codec_open) return 0; #ifdef DEBUG_SILK16 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "##### BEGIN DECODE ******** decoding frame size: %d\n", size); #endif env->GetByteArrayRegion(encoded, RTP_HDR_SIZE, size, buffer); // outPtr = output_buffer; // tot_len = 0; // frames = 0; // do { ret = SKP_Silk_SDK_Decode( psDec, &DecControl, 0,(SKP_uint8 *) buffer, size, output_buffer,&len ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!! SKP_Silk_SDK_Decode returned: %d\n", ret); Print_Decode_Error_Msg(ret); } #ifdef DEBUG_SILK16 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "##### DECODED length: %d\n\t Frame #: %d", len); #endif // frames++; // outPtr += len; // tot_len += len; // } while( DecControl.moreInternalDecoderFrames ); env->SetShortArrayRegion(lin, 0, len,output_buffer); return (jint)len; } extern "C" JNIEXPORT void JNICALL Java_com_trunkbow_silk_SILK16_close (JNIEnv *env, jobject obj) { if (--codec_open != 0) return; /* Free decoder */ free( psDec ); /* Free Encoder */ free( psEnc ); }
silk24_jni.cpp
#include <jni.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <math.h> /* Define codec specific settings */ #define MAX_BYTES_ENC_PER_FRAME 250 // Equals peak bitrate of 100 kbps #define MAX_BYTES_DEC_PER_FRAME 1024 #define MAX_INPUT_FRAMES 5 #define MAX_LBRR_DELAY 2 #define MAX_FRAME_LENGTH 480 #define MAX_FRAME 480 #include <android/log.h> #define LOG_TAG "silk" // text for log tag #include "SKP_Silk_SDK_API.h" #include "SKP_Silk_SigProc_FIX.h" #undef DEBUG_SILK24 // the header length of the RTP frame (must skip when en/decoding) #define RTP_HDR_SIZE 12 static int codec_open = 0; static JavaVM *gJavaVM; const char *kInterfacePath = "org/sipdroid/pjlib/SILK24"; /* encoder parameters */ SKP_int32 encSizeBytes; void *psEnc; /* default settings */ SKP_int fs_kHz = 24; SKP_int targetRate_bps = 20000; SKP_int packetSize_ms = 20; SKP_int frameSizeReadFromFile_ms = 20; SKP_int packetLoss_perc = 0, smplsSinceLastPacket; SKP_int INBandFec_enabled = 0, DTX_enabled = 0, quiet = 0; SKP_SILK_SDK_EncControlStruct encControl; // Struct for input to encoder /* decoder parameters */ jbyte payloadToDec[ MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES * ( MAX_LBRR_DELAY + 1 ) ]; jshort out[ ( MAX_FRAME_LENGTH << 1 ) * MAX_INPUT_FRAMES ], *outPtr; SKP_int32 decSizeBytes; void *psDec; SKP_SILK_SDK_DecControlStruct DecControl; extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK24_open (JNIEnv *env, jobject obj, jint compression) { int ret; if (codec_open++ != 0) return (jint)0; /* Set the samplingrate that is requested for the output */ DecControl.sampleRate = 24000; /* Create decoder */ ret = SKP_Silk_SDK_Get_Decoder_Size( &decSizeBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_Get_Decoder_Size returned %d", ret ); } #ifdef DEBUG_SILK24 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "### INIT Decoder decSizeBytes = %d\n", decSizeBytes); #endif psDec = malloc( decSizeBytes ); /* Reset decoder */ ret = SKP_Silk_SDK_InitDecoder( psDec ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_InitDecoder returned %d", ret ); } /* Create Encoder */ ret = SKP_Silk_SDK_Get_Encoder_Size( &encSizeBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_Get_Encoder_Size returned %d", ret ); } #ifdef DEBUG_SILK24 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "### INIT Encoder encSizeBytes = %d\n", encSizeBytes); #endif psEnc = malloc( encSizeBytes ); /* Reset Encoder */ ret = SKP_Silk_SDK_InitEncoder( psEnc, &encControl ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "\n!!!!!!!! SKP_Silk_SDK_InitEncoder returned %d", ret ); } /* Set Encoder parameters */ encControl.sampleRate = fs_kHz * 1000; encControl.packetSize = packetSize_ms * fs_kHz; encControl.packetLossPercentage = packetLoss_perc; encControl.useInBandFEC = INBandFec_enabled; encControl.useDTX = DTX_enabled; encControl.complexity = compression; encControl.bitRate = targetRate_bps; return (jint)0; } void Print_Decode_Error_Msg(int errcode) { switch (errcode) { case SKP_SILK_DEC_WRONG_SAMPLING_FREQUENCY: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nOutput sampling frequency lower than internal decoded sampling frequency\n", errcode); break; case SKP_SILK_DEC_PAYLOAD_TOO_LARGE: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPayload size exceeded the maximum allowed 1024 bytes\n", errcode); break; case SKP_SILK_DEC_PAYLOAD_ERROR: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPayload has bit errors\n", errcode); break; } } void Print_Encode_Error_Msg(int errcode) { switch (errcode) { case SKP_SILK_ENC_INPUT_INVALID_NO_OF_SAMPLES: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInput length is not a multiplum of 10 ms, or length is longer than the packet length\n", errcode); break; case SKP_SILK_ENC_FS_NOT_SUPPORTED: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nSampling frequency not 8000, 12000, 16000 or 24000 Hertz \n", errcode); break; case SKP_SILK_ENC_PACKET_SIZE_NOT_SUPPORTED: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nPacket size not 20, 40, 60, 80 or 100 ms\n", errcode); break; case SKP_SILK_ENC_PAYLOAD_BUF_TOO_SHORT: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nAllocated payload buffer too short \n", errcode); break; case SKP_SILK_ENC_WRONG_LOSS_RATE: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nLoss rate not between 0 and 100 percent\n", errcode); break; case SKP_SILK_ENC_WRONG_COMPLEXITY_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nComplexity setting not valid, use 0, 1 or 2\n", errcode); break; case SKP_SILK_ENC_WRONG_INBAND_FEC_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInband FEC setting not valid, use 0 or 1\n", errcode); break; case SKP_SILK_ENC_WRONG_DTX_SETTING: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nDTX setting not valid, use 0 or 1\n", errcode); break; case SKP_SILK_ENC_INTERNAL_ERROR: __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!!!!! Decode_Error_Message: %d\nInternal encoder error\n", errcode); break; } } extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK24_encode (JNIEnv *env, jobject obj, jshortArray lin, jint offset, jbyteArray encoded, jint size) { jbyte enc_payload[ MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES ]; jshort in[ MAX_FRAME_LENGTH * MAX_INPUT_FRAMES ]; int ret,i,frsz=MAX_FRAME; SKP_int16 nBytes; unsigned int lin_pos = 0; if (!codec_open) return 0; #ifdef DEBUG_SILK24 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding frame size: %d\toffset: %d\n", size, offset); #endif for (i = 0; i < size; i+=MAX_FRAME) { #ifdef DEBUG_SILK24 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding frame size: %d\toffset: %d i: %d\n", size, offset, i); #endif env->GetShortArrayRegion(lin, offset + i,frsz, in); /* max payload size */ nBytes = MAX_BYTES_ENC_PER_FRAME * MAX_INPUT_FRAMES; ret = SKP_Silk_SDK_Encode( psEnc, &encControl, in, (SKP_int16)frsz, (SKP_uint8 *)enc_payload, &nBytes ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!! SKP_Silk_Encode returned: %d\n", ret); Print_Encode_Error_Msg(ret); break; } #ifdef DEBUG_SILK24 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "Enocded nBytes: %d\n", nBytes); #endif /* Write payload */ env->SetByteArrayRegion(encoded, RTP_HDR_SIZE+ lin_pos, nBytes, enc_payload); lin_pos += nBytes; } #ifdef DEBUG_SILK24 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "encoding **END** frame size: %d\toffset: %d i: %d lin_pos: %d\n", size, offset, i, lin_pos); #endif return (jint)lin_pos; } extern "C" JNIEXPORT jint JNICALL Java_com_trunkbow_silk_SILK24_decode (JNIEnv *env, jobject obj, jbyteArray encoded, jshortArray lin, jint size) { jbyte buffer [MAX_BYTES_DEC_PER_FRAME * MAX_INPUT_FRAMES * ( MAX_LBRR_DELAY + 1 ) ]; jshort output_buffer[( MAX_FRAME_LENGTH << 1 ) * MAX_INPUT_FRAMES ]; // SKP_int16 *outPtr; int ret; SKP_int16 len; // int tot_len,frames; if (!codec_open) return 0; #ifdef DEBUG_SILK24 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "##### BEGIN DECODE ******** decoding frame size: %d\n", size); #endif env->GetByteArrayRegion(encoded, RTP_HDR_SIZE, size, buffer); // outPtr = output_buffer; // tot_len = 0; // frames = 0; // do { ret = SKP_Silk_SDK_Decode( psDec, &DecControl, 0,(SKP_uint8 *) buffer, size, output_buffer,&len ); if( ret ) { __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "!!!!!!!! SKP_Silk_SDK_Decode returned: %d\n", ret); Print_Decode_Error_Msg(ret); } #ifdef DEBUG_SILK24 __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, "##### DECODED length: %d\n\t Frame #: %d", len); #endif // frames++; // outPtr += len; // tot_len += len; // } while( DecControl.moreInternalDecoderFrames ); env->SetShortArrayRegion(lin, 0, len,output_buffer); return (jint)len; } extern "C" JNIEXPORT void JNICALL Java_com_trunkbow_silk_SILK24_close (JNIEnv *env, jobject obj) { if (--codec_open != 0) return; /* Free decoder */ free( psDec ); /* Free Encoder */ free( psEnc ); }
6、在Java层创建Speex工具类，内容如下：
Silk8.java：
class SILK8{ /* * | fs (Hz) | BR (kbps) * ----------------+---------+--------- * Narrowband | 8000 | 6 -20 * Mediumband | 12000 | 7 -25 * Wideband | 16000 | 8 -30 * Super Wideband | 24000 | 12 -40 * * Table 1: fs specifies the audio sampling frequency in Hertz (Hz); BR * specifies the adaptive bit rate range in kilobits per second (kbps). * * Complexity can be scaled to optimize for CPU resources in real-time, * mostly in trade-off to network bit rate. 0 is least CPU demanding and * highest bit rate. */ private static final int DEFAULT_COMPLEXITY = 0; void load() { System.loadLibrary("silk8_jni"); } public native int open(int compression); public native int decode(byte encoded[], short lin[], int size); public native int encode(short lin[], int offset, byte encoded[], int size); public native void close(); }
Silk16.java：
class SILK16 { /* * | fs (Hz) | BR (kbps) * ----------------+---------+--------- * Narrowband | 8000 | 6 -20 * Mediumband | 12000 | 7 -25 * Wideband | 16000 | 8 -30 * Super Wideband | 24000 | 12 -40 * * Table 1: fs specifies the audio sampling frequency in Hertz (Hz); BR * specifies the adaptive bit rate range in kilobits per second (kbps). * * Complexity can be scaled to optimize for CPU resources in real-time, * mostly in trade-off to network bit rate. 0 is least CPU demanding and * highest bit rate. */ private static final int DEFAULT_COMPLEXITY = 0; void load() { System.loadLibrary("silk16_jni"); } public native int open(int compression); public native int decode(byte encoded[], short lin[], int size); public native int encode(short lin[], int offset, byte encoded[], int size); public native void close(); }
Silk24.java：
class SILK24 { /* * | fs (Hz) | BR (kbps) * ----------------+---------+--------- * Narrowband | 8000 | 6 -20 * Mediumband | 12000 | 7 -25 * Wideband | 16000 | 8 -30 * Super Wideband | 24000 | 12 -40 * * Table 1: fs specifies the audio sampling frequency in Hertz (Hz); BR * specifies the adaptive bit rate range in kilobits per second (kbps). * * Complexity can be scaled to optimize for CPU resources in real-time, * mostly in trade-off to network bit rate. 0 is least CPU demanding and * highest bit rate. */ private static final int DEFAULT_COMPLEXITY = 0; void load() { System.loadLibrary("silk24_jni"); } public native int open(int compression); public native int decode(byte encoded[], short lin[], int size); public native int encode(short lin[], int offset, byte encoded[], int size); public native void close(); }
7、使用cygwin编译，生成so文件。
***********************************************************************
* 转载务必在明显处注明：http://blog.csdn.net/xyz_lmn *
* 作者：张兴业 *
* 邮箱：xy-zhang@163.com *
***********************************************************************
参考：http://developer.skype.com/silk
http://blog.csdn.net/wanggp_2007/article/details/5540686 Skype SILK vs. iLBC vs. Speex
本文转自xyz_lmn51CTO博客，原文链接：
http://blog.51cto.com/xyzlmn/1230784
，如需转载请自行联系原作者
