Adds an audio extractor

src/main/java/net/knarcraft/ffmpegconverter/FFMpegConvert.java

@@ -3,6 +3,7 @@ package net.knarcraft.ffmpegconverter;
 import net.knarcraft.ffmpegconverter.config.Configuration;
 import net.knarcraft.ffmpegconverter.converter.AnimeConverter;
 import net.knarcraft.ffmpegconverter.converter.AudioConverter;
+import net.knarcraft.ffmpegconverter.converter.AudioExtractor;
 import net.knarcraft.ffmpegconverter.converter.AudioToVorbisConverter;
 import net.knarcraft.ffmpegconverter.converter.Converter;
 import net.knarcraft.ffmpegconverter.converter.DownScaleConverter;
@@ -100,13 +101,14 @@ public class FFMpegConvert {
                 10. Anime to h265 all streams
                 11. Stream reorder
                 12. Letterbox cropper
-                13. Video's Audio to vorbis converter""", 1, 13);
+                13. Video's Audio to vorbis converter
+                14. Audio from video extractor""", 1, 14, Integer.MIN_VALUE);
 
         return switch (choice) {
             case 1 -> generateWebAnimeConverter();
-            case 2 -> new AudioConverter(FFPROBE_PATH, FFMPEG_PATH, getChoice("<output extension>"));
-            case 3 -> new VideoConverter(FFPROBE_PATH, FFMPEG_PATH, getChoice("<output extension>"));
-            case 4 -> new WebVideoConverter(FFPROBE_PATH, FFMPEG_PATH, getChoice("<output extension>"));
+            case 2 -> new AudioConverter(FFPROBE_PATH, FFMPEG_PATH, getChoice("<output audio extension>", null));
+            case 3 -> new VideoConverter(FFPROBE_PATH, FFMPEG_PATH, getChoice("<output video extension>", null));
+            case 4 -> new WebVideoConverter(FFPROBE_PATH, FFMPEG_PATH, getChoice("<output video extension>", null));
             case 5 -> new MkvH264Converter(FFPROBE_PATH, FFMPEG_PATH);
             case 6 -> new MkvH265ReducedConverter(FFPROBE_PATH, FFMPEG_PATH);
             case 7 -> generateMKVToMP4Transcoder();
@@ -116,6 +118,8 @@ public class FFMpegConvert {
             case 11 -> generateStreamOrderConverter();
             case 12 -> new LetterboxCropper(FFPROBE_PATH, FFMPEG_PATH);
             case 13 -> new AudioToVorbisConverter(FFPROBE_PATH, FFMPEG_PATH);
+            case 14 -> new AudioExtractor(FFPROBE_PATH, FFMPEG_PATH, getChoice("<output audio extension>",
+                    "mp3"), getChoice("<stream to extract>", 0, 1000, 0));
             default -> null;
         };
     }
@@ -182,9 +186,9 @@ public class FFMpegConvert {
     private static Converter generateMKVToMP4Transcoder() {
         OutputUtil.println("[Audio stream index 0-n] [Subtitle stream index 0-n] [Video stream index 0-n]\nYour input: ");
         List<String> input = readInput(3);
-        int audioStreamIndex = -1;
-        int subtitleStreamIndex = -1;
-        int videoStreamIndex = -1;
+        int audioStreamIndex = 0;
+        int subtitleStreamIndex = 0;
+        int videoStreamIndex = 0;
 
         try {
             if (!input.isEmpty()) {
@@ -332,15 +336,19 @@ public class FFMpegConvert {
      * Gets the user's choice
      *
      * @param prompt       <p>The prompt shown to the user.</p>
+     * @param defaultValue <p>The default value, if no input is given</p>
      * @return <p>The non-empty choice given by the user.</p>
      */
     @NotNull
-    private static String getChoice(@NotNull String prompt) {
+    private static String getChoice(@NotNull String prompt, @Nullable Object defaultValue) {
         OutputUtil.println(prompt);
         String choice = "";
         while (choice.isEmpty()) {
             OutputUtil.println("Your input: ");
             choice = READER.nextLine();
+            if (choice.isEmpty() && defaultValue != null) {
+                return String.valueOf(defaultValue);
+            }
         }
         return choice;
     }
@@ -353,7 +361,7 @@ public class FFMpegConvert {
      * @param max    The maximum allowed value
      * @return The value given by the user
      */
-    private static int getChoice(@NotNull String prompt, int min, int max) {
+    private static int getChoice(@NotNull String prompt, int min, int max, int defaultValue) {
         OutputUtil.println(prompt);
         int choice = Integer.MIN_VALUE;
         do {
@@ -361,6 +369,9 @@ public class FFMpegConvert {
             try {
                 choice = Integer.parseInt(READER.next());
             } catch (NumberFormatException e) {
+                if (defaultValue != Integer.MIN_VALUE) {
+                    return defaultValue;
+                }
                 OutputUtil.println("Invalid choice. Please try again.");
             } finally {
                 READER.nextLine();

src/main/java/net/knarcraft/ffmpegconverter/converter/AudioExtractor.java

@@ -0,0 +1,65 @@
+package net.knarcraft.ffmpegconverter.converter;
+
+import net.knarcraft.ffmpegconverter.container.FFMpegCommand;
+import net.knarcraft.ffmpegconverter.container.StreamProbeResult;
+import net.knarcraft.ffmpegconverter.converter.module.ConverterModule;
+import net.knarcraft.ffmpegconverter.converter.module.DebugModule;
+import net.knarcraft.ffmpegconverter.converter.module.ModuleExecutor;
+import net.knarcraft.ffmpegconverter.converter.module.mapping.NthAudioStreamModule;
+import net.knarcraft.ffmpegconverter.converter.module.output.SetOutputFileModule;
+import net.knarcraft.ffmpegconverter.utility.FFMpegHelper;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * An extractor for getting audio streams from video files
+ */
+public class AudioExtractor extends AbstractConverter {
+
+    private final int streamToExtract;
+
+    /**
+     * Instantiates a new audio extractor
+     *
+     * @param ffprobePath     <p>Path/command to ffprobe.</p>
+     * @param ffmpegPath      <p>Path/command to ffmpeg.</p>
+     * @param newExtension    <p>The extension of the new file.</p>
+     * @param streamToExtract <p>The stream to be extracted from the video file</p>
+     */
+    public AudioExtractor(@NotNull String ffprobePath, @NotNull String ffmpegPath, @NotNull String newExtension,
+                          int streamToExtract) {
+        super(newExtension);
+        this.ffprobePath = ffprobePath;
+        this.ffmpegPath = ffmpegPath;
+        this.streamToExtract = Math.max(0, streamToExtract);
+    }
+
+    @Override
+    @Nullable
+    public FFMpegCommand generateConversionCommand(@NotNull String executable, @NotNull StreamProbeResult probeResult,
+                                                   @NotNull String outFile) {
+        FFMpegCommand command = FFMpegHelper.getFFMpegGeneralFileCommand(executable, probeResult.parsedFiles());
+        List<ConverterModule> modules = new ArrayList<>();
+
+        if (this.debug) {
+            modules.add(new DebugModule());
+        }
+
+        //Gets the first audio stream from the file and adds it to the output file
+        modules.add(new NthAudioStreamModule(probeResult.getAudioStreams(), streamToExtract));
+        modules.add(new SetOutputFileModule(outFile));
+
+        new ModuleExecutor(command, modules).execute();
+        return command;
+    }
+
+    @Override
+    @NotNull
+    public List<String> getValidFormats() {
+        return videoFormats;
+    }
+
+}

src/main/resources/audio_formats.txt

@@ -38,3 +38,4 @@ wv
 webm
 8svx
 mka
+ac3