JavaCPP FFMpeg to JavaSound - audio

Question

I have a problem to be able to read audio using JavaCPP FFMpeg library. I don’t know how to pass it to java sound and I don’t know too if my code is correct.
Let’s see the more important part of my code (video is OK so I drop this) :
The variables :
//==========================================================================
// FFMpeg 4.x - Video and Audio
//==========================================================================
private final AVFormatContext pFormatCtx = new AVFormatContext(null);
private final AVDictionary OPTIONS_DICT = null;
private AVPacket pPacket = new AVPacket();
//==========================================================================
// FFMpeg 4.x - Audio
//==========================================================================
private AVCodec pAudioCodec;
private AVCodecContext pAudioCodecCtx;
private final List<StreamInfo> audioStreams = new ArrayList<>();
private int audio_data_size;
private final BytePointer audio_data = new BytePointer(0);
private int audio_ret;
private AVFrame pAudioDecodedFrame = null;
private AVCodecParserContext pAudioParser;
private SwrContext audio_swr_ctx = null;
Then I call prepare functions in this order :
private void prepareFirst() throws Exception{
oldFile = file;
// Initialize packet and check for error
pPacket = av_packet_alloc();
if(pPacket == null){
throw new Exception("ALL: Couldn't allocate packet");
}
// Open video file
if (avformat_open_input(pFormatCtx, file.getPath(), null, null) != 0) {
throw new Exception("ALL: Couldn't open file");
}
// Retrieve stream information
if (avformat_find_stream_info(pFormatCtx, (PointerPointer)null) < 0) {
throw new Exception("ALL: Couldn't find stream information");
}
// Dump information about file onto standard error
av_dump_format(pFormatCtx, 0, file.getPath(), 0);
// Find the first audio/video stream
for (int i = 0; i < pFormatCtx.nb_streams(); i++) {
switch(pFormatCtx.streams(i).codecpar().codec_type()){
case AVMEDIA_TYPE_VIDEO -> videoStreams.add(new StreamInfo(i, pFormatCtx.streams(i)));
case AVMEDIA_TYPE_AUDIO -> audioStreams.add(new StreamInfo(i, pFormatCtx.streams(i)));
}
}
if(videoStreams.isEmpty() && type != PlayType.AudioOnly){
throw new Exception("Didn't find an audio stream");
}
if(audioStreams.isEmpty() && type != PlayType.VideoOnly){
throw new Exception("Didn't find a video stream");
}
}
private void prepareAudio() throws Exception{
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// AUDIO
//------------------------------------------------------------------
if(audioStreams.isEmpty() == false){
//===========================
//------------
// // Let's search for AVCodec
// pAudioCodec = avcodec_find_decoder(pFormatCtx.streams(audioStreams.get(0).getStreamIndex()).codecpar().codec_id());
// if (pAudioCodec == null) {
// throw new Exception("AUDIO: Unsupported codec or not found!");
// }
//
// // Let's alloc AVCodecContext
// pAudioCodecCtx = avcodec_alloc_context3(pAudioCodec);
// if (pAudioCodecCtx == null) {
// throw new Exception("AUDIO: Unallocated codec context or not found!");
// }
// Get a pointer to the codec context for the video stream
pAudioCodecCtx = pFormatCtx.streams(audioStreams.get(0).getStreamIndex()).codec();
// Find the decoder for the video stream
pAudioCodec = avcodec_find_decoder(pAudioCodecCtx.codec_id());
if (pAudioCodec == null) {
throw new Exception("AUDIO: Unsupported codec or not found!");
}
//===========================
//------------
/* open it */
if (avcodec_open2(pAudioCodecCtx, pAudioCodec, OPTIONS_DICT) < 0) {
throw new Exception("AUDIO: Could not open codec");
}
pAudioDecodedFrame = av_frame_alloc();
if (pAudioDecodedFrame == null){
throw new Exception("AUDIO: DecodedFrame allocation failed");
}
audio_swr_ctx = swr_alloc_set_opts(
null, // existing Swr context or NULL
AV_CH_LAYOUT_STEREO, // output channel layout (AV_CH_LAYOUT_*)
AV_SAMPLE_FMT_S16, // output sample format (AV_SAMPLE_FMT_*).
44100, // output sample rate (frequency in Hz)
pAudioCodecCtx.channels(), // input channel layout (AV_CH_LAYOUT_*)
pAudioCodecCtx.sample_fmt(), // input sample format (AV_SAMPLE_FMT_*).
pAudioCodecCtx.sample_rate(), // input sample rate (frequency in Hz)
0, // logging level offset
null // parent logging context, can be NULL
);
swr_init(audio_swr_ctx);
av_samples_fill_arrays(
pAudioDecodedFrame.data(), // audio_data,
pAudioDecodedFrame.linesize(), // linesize
audio_data, // buf
(int)AV_CH_LAYOUT_STEREO, // nb_channels
44100, // nb_samples
AV_SAMPLE_FMT_S16, // sample_fmt
0 // align
);
}
// Audio treatment end ---------------------------------------------
//==================================================================
}
And then when I launch the thread :
private void doPlay() throws Exception{
av_init_packet(pPacket);
// Read frames
while (av_read_frame(pFormatCtx, pPacket) >= 0) {
if (type != PlayType.AudioOnly && pPacket.stream_index() == videoStreams.get(0).getStreamIndex()) {
// Is this a packet from the video stream?
decodeVideo();
renewPacket();
}
if (type != PlayType.VideoOnly && pPacket.stream_index() == audioStreams.get(0).getStreamIndex()) {
// Is this a packet from the audio stream?
if(pPacket.size() > 0){
decodeAudio();
renewPacket();
}
}
}
}
private void renewPacket(){
// Free the packet that was allocated by av_read_frame
av_packet_unref(pPacket);
pPacket.data(null);
pPacket.size(0);
av_init_packet(pPacket);
}
And again, this is where I don’t read audio :
private void decodeAudio() throws Exception{
do {
audio_ret = avcodec_send_packet(pAudioCodecCtx, pPacket);
} while(audio_ret == AVERROR_EAGAIN());
System.out.println("packet sent return value: " + audio_ret);
if(audio_ret == AVERROR_EOF || audio_ret == AVERROR_EINVAL()) {
StringBuilder sb = new StringBuilder();
Formatter formatter = new Formatter(sb, Locale.US);
formatter.format("AVERROR(EAGAIN): %d, AVERROR_EOF: %d, AVERROR(EINVAL): %d\n", AVERROR_EAGAIN(), AVERROR_EOF, AVERROR_EINVAL());
formatter.format("Audio frame getting error (%d)!\n", audio_ret);
throw new Exception(sb.toString());
}
audio_ret = avcodec_receive_frame(pAudioCodecCtx, pAudioDecodedFrame);
System.out.println("frame received return value: " + audio_ret);
audio_data_size = av_get_bytes_per_sample(AV_SAMPLE_FMT_S16);
if (audio_data_size < 0) {
/* This should not occur, checking just for paranoia */
throw new Exception("Failed to calculate data size");
}
double frame_nb = 44100d / pAudioCodecCtx.sample_rate() * pAudioDecodedFrame.nb_samples();
long out_count = Math.round(Math.floor(frame_nb));
int out_samples = swr_convert(
audio_swr_ctx,
audio_data,
(int)out_count,
pAudioDecodedFrame.data(0),
pAudioDecodedFrame.nb_samples()
);
if (out_samples < 0) {
throw new Exception("AUDIO: Error while converting");
}
int dst_bufsize = av_samples_get_buffer_size(
pAudioDecodedFrame.linesize(),
(int)AV_CH_LAYOUT_STEREO,
out_samples,
AV_SAMPLE_FMT_S16,
1
);
AudioFormat audioFormat = new AudioFormat(
pAudioDecodedFrame.sample_rate(),
16,
2,
true,
false
);
BytePointer bytePointer = pAudioDecodedFrame.data(0);
ByteBuffer byteBuffer = bytePointer.asBuffer();
byte[] bytes = new byte[byteBuffer.remaining()];
byteBuffer.get(bytes);
try (SourceDataLine sdl = AudioSystem.getSourceDataLine(audioFormat)) {
sdl.open(audioFormat);
sdl.start();
sdl.write(bytes, 0, bytes.length);
sdl.drain();
sdl.stop();
} catch (LineUnavailableException ex) {
Logger.getLogger(AVEntry.class.getName()).log(Level.SEVERE, null, ex);
}
}
Do you have an idea ?