/**
* Decodes one frame from an MPEG audio bitstream.
*
* @param header The header describing the frame to decode.
* @param bitstream The bistream that provides the bits for te body of the frame.
* @return A SampleBuffer containing the decoded samples.
*/
public Obuffer decodeFrame(Header header, Bitstream stream) throws DecoderException {
if (!initialized) {
initialize(header);
}
int layer = header.layer();
output.clear_buffer();
FrameDecoder decoder = retrieveDecoder(header, stream, layer);
decoder.decodeFrame();
output.write_buffer(1);
return output;
}
private void initialize(Header header) throws DecoderException {
// REVIEW: allow customizable scale factor
float scalefactor = 32700.0f;
int mode = header.mode();
int layer = header.layer();
int channels = mode == Header.SINGLE_CHANNEL ? 1 : 2;
// set up output buffer if not set up by client.
if (output == null) output = new SampleBuffer(header.frequency(), channels);
float[] factors = equalizer.getBandFactors();
filter1 = new SynthesisFilter(0, scalefactor, factors);
// REVIEW: allow mono output for stereo
if (channels == 2) filter2 = new SynthesisFilter(1, scalefactor, factors);
outputChannels = channels;
outputFrequency = header.frequency();
initialized = true;
}
public void testStream() {
try {
InputStream id3in = in.getRawID3v2();
int size = id3in.available();
Header header = in.readFrame();
if (out != null) {
out.println("--- " + filename + " ---");
out.println("ID3v2Size=" + size);
out.println("version=" + header.version());
out.println("version_string=" + header.version_string());
out.println("layer=" + header.layer());
out.println("frequency=" + header.frequency());
out.println("frequency_string=" + header.sample_frequency_string());
out.println("bitrate=" + header.bitrate());
out.println("bitrate_string=" + header.bitrate_string());
out.println("mode=" + header.mode());
out.println("mode_string=" + header.mode_string());
out.println("slots=" + header.slots());
out.println("vbr=" + header.vbr());
out.println("vbr_scale=" + header.vbr_scale());
out.println("max_number_of_frames=" + header.max_number_of_frames(mp3in.available()));
out.println("min_number_of_frames=" + header.min_number_of_frames(mp3in.available()));
out.println("ms_per_frame=" + header.ms_per_frame());
out.println("frames_per_second=" + (float) ((1.0 / (header.ms_per_frame())) * 1000.0));
out.println("total_ms=" + header.total_ms(mp3in.available()));
out.println("SyncHeader=" + header.getSyncHeader());
out.println("checksums=" + header.checksums());
out.println("copyright=" + header.copyright());
out.println("original=" + header.original());
out.println("padding=" + header.padding());
out.println("framesize=" + header.calculate_framesize());
out.println("number_of_subbands=" + header.number_of_subbands());
}
assertEquals("ID3v2Size", Integer.parseInt(props.getProperty("ID3v2Size")), size);
assertEquals("version", Integer.parseInt(props.getProperty("version")), header.version());
assertEquals("version_string", props.getProperty("version_string"), header.version_string());
assertEquals("layer", Integer.parseInt(props.getProperty("layer")), header.layer());
assertEquals(
"frequency", Integer.parseInt(props.getProperty("frequency")), header.frequency());
assertEquals(
"frequency_string",
props.getProperty("frequency_string"),
header.sample_frequency_string());
assertEquals("bitrate", Integer.parseInt(props.getProperty("bitrate")), header.bitrate());
assertEquals("bitrate_string", props.getProperty("bitrate_string"), header.bitrate_string());
assertEquals("mode", Integer.parseInt(props.getProperty("mode")), header.mode());
assertEquals("mode_string", props.getProperty("mode_string"), header.mode_string());
assertEquals("slots", Integer.parseInt(props.getProperty("slots")), header.slots());
assertEquals("vbr", Boolean.valueOf(props.getProperty("vbr")), new Boolean(header.vbr()));
assertEquals(
"vbr_scale", Integer.parseInt(props.getProperty("vbr_scale")), header.vbr_scale());
assertEquals(
"max_number_of_frames",
Integer.parseInt(props.getProperty("max_number_of_frames")),
header.max_number_of_frames(mp3in.available()));
assertEquals(
"min_number_of_frames",
Integer.parseInt(props.getProperty("min_number_of_frames")),
header.min_number_of_frames(mp3in.available()));
assertTrue(
"ms_per_frame",
Float.parseFloat(props.getProperty("ms_per_frame")) == header.ms_per_frame());
assertTrue(
"frames_per_second",
Float.parseFloat(props.getProperty("frames_per_second"))
== (float) ((1.0 / (header.ms_per_frame())) * 1000.0));
assertTrue(
"total_ms",
Float.parseFloat(props.getProperty("total_ms")) == header.total_ms(mp3in.available()));
assertEquals(
"SyncHeader", Integer.parseInt(props.getProperty("SyncHeader")), header.getSyncHeader());
assertEquals(
"checksums",
Boolean.valueOf(props.getProperty("checksums")),
new Boolean(header.checksums()));
assertEquals(
"copyright",
Boolean.valueOf(props.getProperty("copyright")),
new Boolean(header.copyright()));
assertEquals(
"original",
Boolean.valueOf(props.getProperty("original")),
new Boolean(header.original()));
assertEquals(
"padding", Boolean.valueOf(props.getProperty("padding")), new Boolean(header.padding()));
assertEquals(
"framesize",
Integer.parseInt(props.getProperty("framesize")),
header.calculate_framesize());
assertEquals(
"number_of_subbands",
Integer.parseInt(props.getProperty("number_of_subbands")),
header.number_of_subbands());
in.closeFrame();
} catch (BitstreamException e) {
assertTrue("BitstreamException : " + e.getMessage(), false);
} catch (IOException e) {
assertTrue("IOException : " + e.getMessage(), false);
}
}