[FFmpeg-devel] Decoding Error

[Yamusani Vinay]

Hi All,

      I am developing an android application where i need to play mp3
song.So I ported ffmpeg to android and I enabled all decoders in config
file.So I tried with wav file it is playing fine but if i play mp3 song
then i'm getting negative length i.e(output of avcodec_decode_audio3).I
used the below code.

 JNIEnv* env, jobject obj, jstring file, jbyteArray array) {

jboolean isCopy;

int i;

int audioStream = -1;

int res;

int decoded = 0;

int out_size;

AVFormatContext *pFormatCtx =NULL;

AVCodecContext *aCodecCtx;

AVCodecContext *c = NULL;

AVCodec *aCodec;

AVPacket packet;

jclass cls = (*env)->GetObjectClass(env, obj);

jmethodID play = (*env)->GetMethodID(env, cls, "playSound", "([BI)V"); //At
the begining of your main function

const char * szfile = (*env)->GetStringUTFChars(env, file, &isCopy);

int16_t * pAudioBuffer = (int16_t *) av_malloc(

 AVCODEC_MAX_AUDIO_FRAME_SIZE * 2 + FF_INPUT_BUFFER_PADDING_SIZE);

int16_t * outBuffer = (int16_t *) av_malloc(

 AVCODEC_MAX_AUDIO_FRAME_SIZE * 2 + FF_INPUT_BUFFER_PADDING_SIZE);


 __android_log_print(ANDROID_LOG_INFO, DEBUG_TAG, "RAH28 Starting");

res = avformat_open_input(&pFormatCtx, szfile, NULL,NULL);

if (res != 0) {

 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

  "RAH opening input failed with result: [%d]", res);

}


 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

 "RAH getting stream info");

res = av_find_stream_info(pFormatCtx);

if (res < 0) {

 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

  "RAH getting stream info failed with result: [%d]", res);

}


 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

 "RAH getting audio stream");

for (i = 0; i < pFormatCtx->nb_streams; i++) {

 if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO

  && audioStream < 0) {

 audioStream = i;

 }

}


 if (audioStream == -1) {

 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

  "RAH couldn't find audio stream");

}

__android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

 "RAH audio stream found with result: [%d]", res);


 aCodecCtx = pFormatCtx->streams[audioStream]->codec;

__android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

 "RAH audio codec info loaded");


 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

 "RAH audio codec info [%d]", aCodecCtx->codec_id);


 aCodec = avcodec_find_decoder(aCodecCtx->codec_id);

if (!aCodec) {

 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

  "RAH audio codec unsupported");

}

__android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

 "RAH audio codec info found");


 res = avcodec_open2(aCodecCtx, aCodec,NULL);

__android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

 "RAH audio codec loaded [%d] [%d]", aCodecCtx->sample_fmt, res);


// c=avcodec_alloc_context3();

av_init_packet(&packet);


 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

 "RAH channels [%d] sample rate [%d] sample format [%d]",

 aCodecCtx->channels, aCodecCtx->sample_rate, aCodecCtx->sample_fmt);


 int x, y;

x = 0;

y = 0;

while (av_read_frame(pFormatCtx, &packet) >= 0) {

 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

  "RAH frame read: [%d] [%d]", x++, y);


 if (aCodecCtx->codec_type == AVMEDIA_TYPE_AUDIO) {

 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

  "RAH audio ready");

 int data_size = AVCODEC_MAX_AUDIO_FRAME_SIZE

  * 2+FF_INPUT_BUFFER_PADDING_SIZE;

 int size = packet.size;

 y = 0;

 decoded = 0;

 __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

  "RAH packet size: [%d]", size);

 while (size > 0) {

  __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

   "RAH decoding: [%d] [%d]", x, y++);


  int len = avcodec_decode_audio3(aCodecCtx, pAudioBuffer,

   &data_size, &packet);


  __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG,

   "RAH 1 size [%d] len [%d] data_size [%d] out_size [%d]",

   size, len, data_size, out_size);

  jbyte *bytes = (*env)->GetByteArrayElements(env, array, NULL);


//                                memmove(bytes + decoded, (jbyte *)
(pAudioBuffer), 192000);

  memcpy(bytes + decoded, pAudioBuffer, len); //


  __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "RAH 2");


  (*env)->ReleaseByteArrayElements(env, array, bytes, 0);

  __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "RAH 3");


  (*env)->CallVoidMethod(env, obj, play, array, len);

  __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "RAH 4");


  size -= len;

  decoded += len;


  }

 av_free_packet(&packet);

 }


 }


 // Close the video file

av_close_input_file(pFormatCtx);


 //__android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "RAH Finished Running
result: [%d]", res);

(*env)->ReleaseStringUTFChars(env, file, szfile);


Thanks & Regards
bitfield