REFACTOR clipService and ADD ffmpegService

src/main/java/com/ddf/vodsystem/services/FfmpegService.java

@@ -0,0 +1,91 @@
+package com.ddf.vodsystem.services;
+
+import com.ddf.vodsystem.entities.VideoMetadata;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Service;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+@Service
+public class FfmpegService {
+    private static final Logger logger = LoggerFactory.getLogger(FfmpegService.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 void buildFilters(ArrayList<String> command, Float fps, Integer width, Integer height) {
+        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);
+        }
+
+        if (!filters.isEmpty()) {
+            logger.info("Adding video filters");
+            command.add("-vf");
+            command.add(String.join(",", filters));
+        }
+    }
+
+    private void buildBitrate(ArrayList<String> command, Float length, Float fileSize) {
+        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");
+    }
+
+    private void buildInputs(ArrayList<String> command, File inputFile, Float startPoint, Float length) {
+        command.add("-ss");
+        command.add(startPoint.toString());
+
+        command.add("-i");
+        command.add(inputFile.getAbsolutePath());
+
+        command.add("-t");
+        command.add(Float.toString(length));
+    }
+
+    public ProcessBuilder buildCommand(File inputFile, File outputFile, VideoMetadata videoMetadata) {
+        ArrayList<String> command = new ArrayList<>();
+        command.add("ffmpeg");
+        command.add("-progress");
+        command.add("pipe:1");
+        command.add("-y");
+
+        Float length = videoMetadata.getEndPoint() - videoMetadata.getStartPoint();
+        buildInputs(command, inputFile, videoMetadata.getStartPoint(), length);
+        buildFilters(command, videoMetadata.getFps(), videoMetadata.getWidth(), videoMetadata.getHeight());
+
+        if (videoMetadata.getFileSize() != null) {
+            buildBitrate(command, length, videoMetadata.getFileSize());
+        }
+
+        // Output file
+        command.add(outputFile.getAbsolutePath());
+        return new ProcessBuilder(command);
+    }
+}