package com.capacitor.audioengine; import android.media.MediaExtractor; import android.media.MediaFormat; import android.media.MediaMetadataRetriever; import android.media.MediaMuxer; import android.os.Build; import android.util.Log; import com.getcapacitor.JSObject; import java.io.File; import java.io.FileInputStream; import java.io.IOException; /** * Handles audio file processing operations including trimming and merging */ public class AudioFileProcessor { private static final String TAG = "AudioFileProcessor"; /** * Get duration of an audio file */ public static double getAudioDuration(String filePath) { try (MediaMetadataRetriever retriever = new MediaMetadataRetriever()) { retriever.setDataSource(filePath); String durationStr = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION); return durationStr != null ? Double.parseDouble(durationStr) / 1000.0 : 0.0; } catch (Exception e) { Log.e(TAG, "Failed to get audio duration for: " + filePath, e); return 0.0; } } /** * Trim audio file from startTime to endTime */ public static void trimAudioFile(File sourceFile, File outputFile, double startTime, double endTime) throws IOException { try (ResourceManager.SafeMediaExtractor safeExtractor = new ResourceManager.SafeMediaExtractor(); ResourceManager.SafeMediaMuxer safeMuxer = new ResourceManager.SafeMediaMuxer( outputFile.getAbsolutePath(), MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4)) { MediaExtractor extractor = safeExtractor.getExtractor(); MediaMuxer muxer = safeMuxer.getMuxer(); extractor.setDataSource(sourceFile.getAbsolutePath()); // Find audio track int audioTrack = findAudioTrack(extractor); if (audioTrack == -1) { throw new IOException("No audio track found in file: " + sourceFile.getAbsolutePath()); } MediaFormat audioFormat = extractor.getTrackFormat(audioTrack); extractor.selectTrack(audioTrack); // Create muxer track int muxerTrack = muxer.addTrack(audioFormat); muxer.start(); // Seek to start time extractor.seekTo((long)(startTime * 1000000), MediaExtractor.SEEK_TO_PREVIOUS_SYNC); // Extract and write data with smaller buffer for better memory management java.nio.ByteBuffer buffer = java.nio.ByteBuffer.allocate(64 * 1024); // 64KB android.media.MediaCodec.BufferInfo bufferInfo = new android.media.MediaCodec.BufferInfo(); long endTimeUs = (long)(endTime * 1000000); long samplesProcessed = 0; while (true) { int sampleSize = extractor.readSampleData(buffer, 0); if (sampleSize < 0) break; long sampleTime = extractor.getSampleTime(); if (sampleTime > endTimeUs) break; bufferInfo.offset = 0; bufferInfo.size = sampleSize; bufferInfo.presentationTimeUs = sampleTime; bufferInfo.flags = convertExtractorFlags(extractor.getSampleFlags()); muxer.writeSampleData(muxerTrack, buffer, bufferInfo); extractor.advance(); samplesProcessed++; } Log.d(TAG, "Audio trimmed successfully from " + startTime + "s to " + endTime + "s, processed " + samplesProcessed + " samples"); } catch (Exception e) { // Clean up output file if trimming failed if (outputFile.exists()) { boolean deleted = outputFile.delete(); if (!deleted) { Log.w(TAG, "Failed to delete output file after trim failure: " + outputFile.getAbsolutePath()); } } throw new IOException("Failed to trim audio file: " + e.getMessage(), e); } } /** * Find audio track in MediaExtractor */ private static int findAudioTrack(MediaExtractor extractor) { for (int i = 0; i < extractor.getTrackCount(); i++) { MediaFormat format = extractor.getTrackFormat(i); String mime = format.getString(MediaFormat.KEY_MIME); if (mime != null && mime.startsWith("audio/")) { return i; } } return -1; } /** * Convert MediaExtractor flags to MediaCodec BufferInfo flags */ private static int convertExtractorFlags(int extractorFlags) { int bufferFlags = 0; if ((extractorFlags & MediaExtractor.SAMPLE_FLAG_SYNC) != 0) { bufferFlags |= android.media.MediaCodec.BUFFER_FLAG_KEY_FRAME; } return bufferFlags; } /** * Get audio file information */ public static JSObject getAudioFileInfo(String filePath) { return getAudioFileInfo(filePath, false); } /** * Get audio file information with optional base64 generation */ public static JSObject getAudioFileInfo(String filePath, boolean includeBase64) { File file = new File(filePath); JSObject info = new JSObject(); try { // Basic file info - matching iOS format info.put("path", filePath); info.put("uri", "file://" + filePath); info.put("webPath", "capacitor://localhost/_capacitor_file_" + filePath); info.put("filename", file.getName()); info.put("size", file.length()); info.put("createdAt", file.lastModified()); if (file.exists()) { // Audio-specific info double duration = getAudioDuration(filePath); info.put("duration", duration); // Format info using MediaMetadataRetriever try (MediaMetadataRetriever retriever = new MediaMetadataRetriever()) { retriever.setDataSource(filePath); String mimeType = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_MIMETYPE); String bitrate = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_BITRATE); // Always use audio/m4a for consistent MIME type across platforms info.put("mimeType", "audio/m4a"); info.put("bitrate", bitrate != null ? Integer.parseInt(bitrate) : 0); // Get number of channels using compatibility method info.put("channels", getAudioChannelsCompat(filePath)); // METADATA_KEY_SAMPLER requires API level 31 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) { String sampleRate = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_SAMPLERATE); info.put("sampleRate", sampleRate != null ? Integer.parseInt(sampleRate) : 0); } else { // For older API levels, try to get sample rate using MediaExtractor info.put("sampleRate", getAudioSampleRateCompat(filePath)); } } catch (Exception e) { Log.w(TAG, "Error with MediaMetadataRetriever", e); } // Generate base64 if requested if (includeBase64) { try { String base64 = generateBase64FromFile(file); info.put("base64", base64); } catch (Exception e) { Log.w(TAG, "Failed to generate base64 for file: " + filePath, e); info.put("base64", ""); // Fallback to empty string } } else { info.put("base64", ""); // Empty for performance } } } catch (Exception e) { Log.e(TAG, "Error getting audio file info", e); info.put("error", e.getMessage()); } return info; } /** * Generate base64 data URI from audio file */ public static String generateBase64FromFile(File file) throws Exception { try (FileInputStream fis = new FileInputStream(file)) { byte[] audioBytes = new byte[(int) file.length()]; int bytesRead = fis.read(audioBytes); if (bytesRead != file.length()) { throw new IOException("Failed to read complete file"); } String base64Data = android.util.Base64.encodeToString(audioBytes, android.util.Base64.NO_WRAP); return "data:audio/m4a;base64," + base64Data; } } /** * Get audio channels for API levels below 29 using MediaExtractor */ private static int getAudioChannelsCompat(String filePath) { MediaExtractor extractor = null; try { extractor = new MediaExtractor(); extractor.setDataSource(filePath); for (int i = 0; i < extractor.getTrackCount(); i++) { MediaFormat format = extractor.getTrackFormat(i); String mime = format.getString(MediaFormat.KEY_MIME); if (mime != null && mime.startsWith("audio/")) { if (format.containsKey(MediaFormat.KEY_CHANNEL_COUNT)) { return format.getInteger(MediaFormat.KEY_CHANNEL_COUNT); } } } } catch (Exception e) { Log.w(TAG, "Failed to get channel count using MediaExtractor", e); } finally { if (extractor != null) { try { extractor.release(); } catch (Exception e) { Log.w(TAG, "Error releasing MediaExtractor", e); } } } return 1; // Default to mono } /** * Get audio sample rate for API levels below 31 using MediaExtractor */ private static int getAudioSampleRateCompat(String filePath) { MediaExtractor extractor = null; try { extractor = new MediaExtractor(); extractor.setDataSource(filePath); for (int i = 0; i < extractor.getTrackCount(); i++) { MediaFormat format = extractor.getTrackFormat(i); String mime = format.getString(MediaFormat.KEY_MIME); if (mime != null && mime.startsWith("audio/")) { if (format.containsKey(MediaFormat.KEY_SAMPLE_RATE)) { return format.getInteger(MediaFormat.KEY_SAMPLE_RATE); } } } } catch (Exception e) { Log.w(TAG, "Failed to get sample rate using MediaExtractor", e); } finally { if (extractor != null) { try { extractor.release(); } catch (Exception e) { Log.w(TAG, "Error releasing MediaExtractor", e); } } } return 0; } }