support on-the-fly conversion of audio files to MP3

silvin-lubecki · Jan 8, 2021 · 37e54e7 · 37e54e7
1 parent f64e2bb
commit 37e54e7
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Showing 4 changed files with 77 additions and 3 deletions.
diff --git a/core/pom.xml b/core/pom.xml
@@ -56,6 +56,11 @@
             <scope>system</scope>
             <systemPath>${project.basedir}/../libs/vorbis-java-1.0.0-beta.jar</systemPath>
         </dependency>
+        <dependency>
+            <groupId>de.sciss</groupId>
+            <artifactId>jump3r</artifactId>
+            <version>1.0.5</version>
+        </dependency>
     </dependencies>
 
 </project>
diff --git a/core/src/main/java/studio/core/v1/utils/AudioConversion.java b/core/src/main/java/studio/core/v1/utils/AudioConversion.java
@@ -6,6 +6,9 @@
 
 package studio.core.v1.utils;
 
+import de.sciss.jump3r.lowlevel.LameEncoder;
+import de.sciss.jump3r.mp3.MPEGMode;
+
 import javax.sound.sampled.*;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -15,7 +18,9 @@ public class AudioConversion {
 
     private static final float WAVE_SAMPLE_RATE = 32000.0f;
     private static final float OGG_SAMPLE_RATE = 44100.0f;
+    private static final float MP3_SAMPLE_RATE = 44100.0f;
     private static final int BITSIZE = 16;
+    private static final int MP3_BITSIZE = 32;
     private static final int CHANNELS = 1;
 
 
@@ -94,4 +99,66 @@ public static byte[] waveToOgg(byte[] waveData) throws IOException {
             throw new IOException("Audio compression to ogg format failed", e);
         }
     }
+
+    public static byte[] anyToMp3(byte[] data) throws IOException {
+        try {
+            AudioInputStream inputAudio = AudioSystem.getAudioInputStream(new ByteArrayInputStream(data));
+
+            // First, convert to PCM
+            AudioFormat pcmFormat = new AudioFormat(
+                    AudioFormat.Encoding.PCM_SIGNED,
+                    inputAudio.getFormat().getSampleRate(),
+                    BITSIZE,
+                    inputAudio.getFormat().getChannels(),
+                    inputAudio.getFormat().getChannels()*2,
+                    inputAudio.getFormat().getSampleRate(),
+                    false
+            );
+            AudioInputStream pcm = AudioSystem.getAudioInputStream(pcmFormat, inputAudio);
+
+            // Then, convert to mono **and oversample** (apparently the input stream in always empty unless the sample rate changes)
+            AudioFormat pcmOverSampledFormat = new AudioFormat(
+                    AudioFormat.Encoding.PCM_SIGNED,
+                    inputAudio.getFormat().getSampleRate()*2,
+                    BITSIZE,
+                    CHANNELS,
+                    CHANNELS*2,
+                    inputAudio.getFormat().getSampleRate()*2,
+                    false
+            );
+            AudioInputStream pcmOverSampled = AudioSystem.getAudioInputStream(pcmOverSampledFormat, pcm);
+
+            // Finally, convert sample rate to 44100Hz and sample bitsize to 32 bits
+            AudioFormat pcm44100Format = new AudioFormat(
+                    AudioFormat.Encoding.PCM_FLOAT,
+                    MP3_SAMPLE_RATE,
+                    MP3_BITSIZE,
+                    CHANNELS,
+                    CHANNELS*4,
+                    MP3_SAMPLE_RATE,
+                    false
+            );
+            AudioInputStream pcm44100 = AudioSystem.getAudioInputStream(pcm44100Format, pcmOverSampled);
+
+            LameEncoder encoder = new LameEncoder(pcm44100.getFormat(), 64, MPEGMode.MONO.ordinal(), 1, false);
+
+            ByteArrayOutputStream mp3 = new ByteArrayOutputStream();
+            byte[] inputBuffer = new byte[encoder.getPCMBufferSize()];
+            byte[] outputBuffer = new byte[encoder.getPCMBufferSize()];
+
+            int bytesRead;
+            int bytesWritten;
+
+            while (0 < (bytesRead = pcm44100.read(inputBuffer))) {
+                bytesWritten = encoder.encodeBuffer(inputBuffer, 0, bytesRead, outputBuffer);
+                mp3.write(outputBuffer, 0, bytesWritten);
+            }
+
+            encoder.close();
+            return mp3.toByteArray();
+        } catch (UnsupportedAudioFileException e) {
+            e.printStackTrace();
+            throw new IOException("Unsupported audio format", e);
+        }
+    }
 }
diff --git a/core/src/main/java/studio/core/v1/utils/ImageConversion.java b/core/src/main/java/studio/core/v1/utils/ImageConversion.java
@@ -129,8 +129,11 @@ private static BufferedImage redrawIndexedImage(BufferedImage inputImage) {
         int[] rgb = outputImage.getRGB(0, 0, outputImage.getWidth(), outputImage.getHeight(), null, 0, outputImage.getWidth());
         int[] cmap = Arrays.stream(rgb).distinct().toArray();
 
+        // Force 16-colors palette
+        int[] cmap16 = Arrays.copyOf(cmap, 16);
+
         // Create indexed image with palette
-        BufferedImage redrawn = new BufferedImage(outputImage.getWidth(), outputImage.getHeight(), BufferedImage.TYPE_BYTE_INDEXED, new IndexColorModel(4, cmap.length, cmap, 0, false, -1, 0));
+        BufferedImage redrawn = new BufferedImage(outputImage.getWidth(), outputImage.getHeight(), BufferedImage.TYPE_BYTE_INDEXED, new IndexColorModel(4, cmap16.length, cmap16, 0, false, -1, 0));
         Graphics2D g2d = redrawn.createGraphics();
         g2d.fillRect(0, 0, redrawn.getWidth(), redrawn.getHeight());
         g2d.drawImage(outputImage, 0, 0, null);

diff --git a/core/src/main/java/studio/core/v1/utils/PackAssetsCompression.java b/core/src/main/java/studio/core/v1/utils/PackAssetsCompression.java
@@ -159,8 +159,7 @@ public static StoryPack withPreparedAssetsFirmware2dot4(StoryPack pack) throws I
                 String assetHash = DigestUtils.sha1Hex(audioData);
                 if (assets.get(assetHash) == null) {
                     if (!"audio/mp3".equals(node.getAudio().getMimeType()) && !"audio/mpeg".equals(node.getAudio().getMimeType())) {
-                        // FIXME Cannot convert to MP3, story pack MUST ALREADY be using MP3 audio files
-                        throw new RuntimeException("Cannot convert to MP3, story pack MUST ALREADY be using MP3 audio files");
+                        audioData = AudioConversion.anyToMp3(audioData);
                     }
                     assets.put(assetHash, audioData);
                 }