20 modularize the code to split up large classes (#21)

* MODULARIZE ClipService by introducing CompressionService, MetadataService, and ThumbnailService

* ADD deleteClip functionality to ClipController

src/main/java/com/ddf/vodsystem/services/media/CompressionService.java

@@ -0,0 +1,123 @@
+package com.ddf.vodsystem.services.media;
+
+import com.ddf.vodsystem.dto.ProgressTracker;
+import com.ddf.vodsystem.dto.VideoMetadata;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Service;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+@Service
+public class CompressionService {
+    private static final Logger logger = LoggerFactory.getLogger(CompressionService.class);
+
+    private static final float AUDIO_RATIO = 0.15f;
+    private static final float MAX_AUDIO_BITRATE = 128f;
+    private static final float BITRATE_MULTIPLIER = 0.9f;
+    private final Pattern timePattern = Pattern.compile("out_time_ms=(\\d+)");
+
+    public void compress(File inputFile, File outputFile, VideoMetadata videoMetadata, ProgressTracker progress) throws IOException, InterruptedException {
+        logger.info("Compressing video from {} to {}", inputFile.getAbsolutePath(), outputFile.getAbsolutePath());
+
+        float length = videoMetadata.getEndPoint() - videoMetadata.getStartPoint();
+        List<String> command = buildCommand(inputFile, outputFile, videoMetadata);
+        CommandRunner.run(command, line -> setProgress(line, progress, length));
+    }
+
+    private void setProgress(String line, ProgressTracker progress, float length) {
+        Matcher matcher = timePattern.matcher(line);
+        if (matcher.find()) {
+            float timeInMs = Float.parseFloat(matcher.group(1)) / 1000000f;
+            progress.setProgress(timeInMs / length);
+        }
+    }
+
+    private List<String> buildFilters(Float fps, Integer width, Integer height) {
+        List<String> command = new ArrayList<>();
+        command.add("-vf");
+
+        List<String> filters = new ArrayList<>();
+
+        if (fps != null) {
+            logger.info("Frame rate set to {}", fps);
+            filters.add("fps=" + fps);
+        }
+
+        if (!(width == null && height == null)) {
+            logger.info("Scaling video to width: {}, height: {}", width, height);
+            String w = (width != null) ? width.toString() : "-1";
+            String h = (height != null) ? height.toString() : "-1";
+            filters.add("scale=" + w + ":" + h);
+        }
+
+        logger.info("Adding video filters");
+        command.add(String.join(",", filters));
+        return command;
+    }
+
+    private List<String> buildBitrate(Float length, Float fileSize) {
+        List<String> command = new ArrayList<>();
+
+        float bitrate = ((fileSize * 8) / length) * BITRATE_MULTIPLIER;
+        float audioBitrate = bitrate * AUDIO_RATIO;
+        float videoBitrate;
+
+        if (audioBitrate > MAX_AUDIO_BITRATE) {
+            audioBitrate = MAX_AUDIO_BITRATE;
+            videoBitrate = bitrate - MAX_AUDIO_BITRATE;
+        } else {
+            videoBitrate = bitrate * (1 - AUDIO_RATIO);
+        }
+
+        command.add("-b:v");
+        command.add(videoBitrate + "k");
+        command.add("-b:a");
+        command.add(audioBitrate + "k");
+
+        return command;
+    }
+
+    private List<String> buildInputs(File inputFile, Float startPoint, Float length) {
+        List<String> command = new ArrayList<>();
+
+        command.add("-ss");
+        command.add(startPoint.toString());
+
+        command.add("-i");
+        command.add(inputFile.getAbsolutePath());
+
+        command.add("-t");
+        command.add(Float.toString(length));
+
+        return command;
+    }
+
+    private List<String> buildCommand(File inputFile, File outputFile, VideoMetadata videoMetadata) {
+        List<String> command = new ArrayList<>();
+        command.add("ffmpeg");
+        command.add("-progress");
+        command.add("pipe:1");
+        command.add("-y");
+
+        Float length = videoMetadata.getEndPoint() - videoMetadata.getStartPoint();
+        command.addAll(buildInputs(inputFile, videoMetadata.getStartPoint(), length));
+
+        if (videoMetadata.getFps() != null || videoMetadata.getWidth() != null || videoMetadata.getHeight() != null) {
+            command.addAll(buildFilters(videoMetadata.getFps(), videoMetadata.getWidth(), videoMetadata.getHeight()));
+        }
+
+        if (videoMetadata.getFileSize() != null) {
+            command.addAll(buildBitrate(length, videoMetadata.getFileSize()));
+        }
+
+        // Output file
+        command.add(outputFile.getAbsolutePath());
+        return command;
+    }
+}