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#1170 resolves issue with MP3 encoded audio raspy. Adds auto-clipping of PCM audio prior to encoding and adds 4x new 32-bit input sample rate selections to choose from, in addition to original 4x 16-bit input formats. (#1171)

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Co-authored-by: Dennis Sheirer <dsheirer@github.com>
This commit is contained in:
Denny Sheirer
2022-03-16 05:00:07 -04:00
committed by GitHub
parent 90bc321aca
commit 7749fd10f1
23 changed files with 245 additions and 183 deletions
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35
src/main/java/io/github/dsheirer/audio/convert/MP3AudioConverter.java
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@@ -32,6 +32,9 @@ import java.util.Arrays;
import java.util.Collections;
import java.util.List;
/**
* Converts PCM audio packets to Mono, MP3 encoded audio
*/
public class MP3AudioConverter implements IAudioConverter
{
private final static Logger mLog = LoggerFactory.getLogger( MP3AudioConverter.class );
@@ -40,25 +43,33 @@ public class MP3AudioConverter implements IAudioConverter
private RealResampler mResampler;
private ByteArrayOutputStream mMP3EncodedFramesStream = new ByteArrayOutputStream();
private byte[] mOutputFramesBuffer;
private InputAudioFormat mInputAudioFormat;
/**
* Converts PCM 16-bit Little Endian audio packets to Mono, MP3 compressed audio.
* Constructs an instance.
*
* @param audioSampleRate for the desired input sample rate (resampled from default 8 kHz as needed)
* @param inputAudioFormat for the desired input sample rate and bit size (resampled from default 8 kHz as needed)
* @param setting to configure the LAME encoder
*/
public MP3AudioConverter(AudioSampleRate audioSampleRate, MP3Setting setting)
public MP3AudioConverter(InputAudioFormat inputAudioFormat, MP3Setting setting)
{
mEncoder = LameFactory.getLameEncoder(audioSampleRate, setting);
mInputAudioFormat = inputAudioFormat;
mEncoder = LameFactory.getLameEncoder(inputAudioFormat, setting);
if(audioSampleRate != AudioSampleRate.SR_8000)
//Resampling is only required if desired input sample rate is not system default of 8kHz
if(inputAudioFormat != InputAudioFormat.SR_8000 && inputAudioFormat != InputAudioFormat.SR_32_8000)
{
mResampler = LameFactory.getResampler(audioSampleRate);
mResampler = LameFactory.getResampler(inputAudioFormat);
}
mOutputFramesBuffer = new byte[mEncoder.getPCMBufferSize()];
}
/**
* Converts the list of PCM audio packets to MP3 encoded.
* @param audioPackets of PCM audio sampled at 8 kHz
* @return encoded MP3 audio
*/
public List<byte[]> convert(List<float[]> audioPackets)
{
List<byte[]> converted = new ArrayList<>();
@@ -70,7 +81,17 @@ public class MP3AudioConverter implements IAudioConverter
for(int x = 0; x < audioPackets.size(); x++)
{
byte[] bytesToEncode = ConversionUtils.convertToSigned16BitSamples(audioPackets.get(x)).array();
byte[] bytesToEncode = null;
if(mInputAudioFormat.getAudioFormat().getSampleSizeInBits() == 16)
{
bytesToEncode = ConversionUtils.convertToSigned16BitSamples(audioPackets.get(x)).array();
}
else
{
bytesToEncode = ConversionUtils.convertToSigned32BitSamples(audioPackets.get(x)).array();
}
int bytesToEncodePointer = 0;
int inputChunkSize = FastMath.min(mOutputFramesBuffer.length, bytesToEncode.length);