Java tutorial
/** * Licensed to The Apereo Foundation under one or more contributor license * agreements. See the NOTICE file distributed with this work for additional * information regarding copyright ownership. * * * The Apereo Foundation licenses this file to you under the Educational * Community License, Version 2.0 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy of the License * at: * * http://opensource.org/licenses/ecl2.txt * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. * */ package org.opencastproject.silencedetection.ffmpeg; import com.google.common.io.LineReader; import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStreamReader; import java.text.DecimalFormat; import java.text.DecimalFormatSymbols; import java.util.LinkedList; import java.util.List; import java.util.Locale; import java.util.Properties; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.commons.lang.StringUtils; import org.opencastproject.mediapackage.MediaPackageException; import org.opencastproject.mediapackage.Track; import org.opencastproject.silencedetection.api.MediaSegment; import org.opencastproject.silencedetection.api.MediaSegments; import org.opencastproject.silencedetection.api.SilenceDetectionFailedException; import org.opencastproject.silencedetection.impl.SilenceDetectionProperties; import org.opencastproject.util.NotFoundException; import org.opencastproject.workspace.api.Workspace; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Find silent sequences in audio stream using Gstreamer. */ public class FFmpegSilenceDetector { private static final Logger logger = LoggerFactory.getLogger(FFmpegSilenceDetector.class); public static final String FFMPEG_BINARY_CONFIG = "org.opencastproject.composer.ffmpeg.path"; public static final String FFMPEG_BINARY_DEFAULT = "ffmpeg"; private static final String DEFAULT_SILENCE_MIN_LENGTH = "5000"; private static final String DEFAULT_SILENCE_PRE_LENGTH = "2000"; private static final String DEFAULT_THRESHOLD_DB = "-40dB"; private static final String DEFAULT_VOICE_MIN_LENGTH = "60000"; private String filePath; private String trackId; private List<MediaSegment> segments = null; /** * Create nonsilent sequences detection pipeline. * Parse audio stream and store all positions, where the volume level fall under the threshold. * * @param properties * @param track source track */ public FFmpegSilenceDetector(Properties properties, Track track, Workspace workspace) throws SilenceDetectionFailedException, MediaPackageException, IOException { long minSilenceLength = Long.parseLong( properties.getProperty(SilenceDetectionProperties.SILENCE_MIN_LENGTH, DEFAULT_SILENCE_MIN_LENGTH)); long minVoiceLength = Long.parseLong( properties.getProperty(SilenceDetectionProperties.VOICE_MIN_LENGTH, DEFAULT_VOICE_MIN_LENGTH)); long preSilenceLength = Long.parseLong( properties.getProperty(SilenceDetectionProperties.SILENCE_PRE_LENGTH, DEFAULT_SILENCE_PRE_LENGTH)); String thresholdDB = properties.getProperty(SilenceDetectionProperties.SILENCE_THRESHOLD_DB, DEFAULT_THRESHOLD_DB); String binary = properties.getProperty(FFMPEG_BINARY_CONFIG, FFMPEG_BINARY_DEFAULT); trackId = track.getIdentifier(); /* Make sure the element can be analyzed using this analysis implementation */ if (!track.hasAudio()) { logger.warn("Track {} has no audio stream to run a silece detection on", trackId); throw new SilenceDetectionFailedException("Element has no audio stream"); } /* Make sure we are not allowed to move the beginning of a segment into the last segment */ if (preSilenceLength > minSilenceLength) { logger.error("Pre silence length ({}) is configured to be greater than minimun silence length ({})", preSilenceLength, minSilenceLength); throw new SilenceDetectionFailedException("preSilenceLength > minSilenceLength"); } try { File mediaFile = workspace.get(track.getURI()); filePath = mediaFile.getAbsolutePath(); } catch (NotFoundException e) { throw new SilenceDetectionFailedException("Error finding the media file in workspace", e); } catch (IOException e) { throw new SilenceDetectionFailedException("Error reading media file in workspace", e); } if (track.getDuration() == null) { throw new MediaPackageException("Track " + trackId + " does not have a duration"); } logger.info("Track {} loaded, duration is {} s", filePath, track.getDuration() / 1000); logger.info("Starting silence detection of {}", filePath); String mediaPath = filePath.replaceAll(" ", "\\ "); DecimalFormat decimalFmt = new DecimalFormat("0.000", new DecimalFormatSymbols(Locale.US)); String minSilenceLengthInSeconds = decimalFmt.format((double) minSilenceLength / 1000.0); String filter = "silencedetect=noise=" + thresholdDB + ":duration=" + minSilenceLengthInSeconds; String[] command = new String[] { binary, "-nostats", "-i", mediaPath, "-filter:a", filter, "-f", "null", "-" }; String commandline = StringUtils.join(command, " "); logger.info("Running {}", commandline); ProcessBuilder pbuilder = new ProcessBuilder(command); List<String> segmentsStrings = new LinkedList<String>(); Process process = pbuilder.start(); BufferedReader reader = new BufferedReader(new InputStreamReader(process.getErrorStream())); try { LineReader lr = new LineReader(reader); String line = lr.readLine(); while (null != line) { /* We want only lines from the silence detection filter */ logger.debug("FFmpeg output: {}", line); if (line.startsWith("[silencedetect ")) { segmentsStrings.add(line); } line = lr.readLine(); } } catch (IOException e) { logger.error("Error executing ffmpeg: {}", e.getMessage()); } finally { reader.close(); } /** * Example output: * [silencedetect @ 0x2968e40] silence_start: 466.486 * [silencedetect @ 0x2968e40] silence_end: 469.322 | silence_duration: 2.83592 */ LinkedList<MediaSegment> segmentsTmp = new LinkedList<MediaSegment>(); if (segmentsStrings.size() == 0) { /* No silence found -> Add one segment for the whole track */ logger.info("No silence found. Adding one large segment."); segmentsTmp.add(new MediaSegment(0, track.getDuration())); } else { long lastSilenceEnd = 0; long lastSilenceStart = 0; Pattern patternStart = Pattern.compile("silence_start\\:\\ \\d+\\.\\d+"); Pattern patternEnd = Pattern.compile("silence_end\\:\\ \\d+\\.\\d+"); for (String seginfo : segmentsStrings) { /* Match silence ends */ Matcher matcher = patternEnd.matcher(seginfo); String time = ""; while (matcher.find()) { time = matcher.group().substring(13); } if (!"".equals(time)) { long silenceEnd = (long) (Double.parseDouble(time) * 1000); if (silenceEnd > lastSilenceEnd) { logger.debug("Found silence end at {}", silenceEnd); lastSilenceEnd = silenceEnd; } continue; } /* Match silence start -> End of segments */ matcher = patternStart.matcher(seginfo); time = ""; while (matcher.find()) { time = matcher.group().substring(15); } if (!"".equals(time)) { lastSilenceStart = (long) (Double.parseDouble(time) * 1000); logger.debug("Found silence start at {}", lastSilenceStart); if (lastSilenceStart - lastSilenceEnd > minVoiceLength) { /* Found a valid segment */ long segmentStart = java.lang.Math.max(0, lastSilenceEnd - preSilenceLength); logger.info("Adding segment from {} to {}", segmentStart, lastSilenceStart); segmentsTmp.add(new MediaSegment(segmentStart, lastSilenceStart)); } } } /* Add last segment if it is no silence and the segment is long enough */ if (lastSilenceStart < lastSilenceEnd && track.getDuration() - lastSilenceEnd > minVoiceLength) { long segmentStart = java.lang.Math.max(0, lastSilenceEnd - preSilenceLength); logger.info("Adding final segment from {} to {}", segmentStart, track.getDuration()); segmentsTmp.add(new MediaSegment(segmentStart, track.getDuration())); } } logger.info("Segmentation of track {} yielded {} segments", trackId, segmentsTmp.size()); segments = segmentsTmp; } /** * Returns found media segments. * @return nonsilent media segments */ public MediaSegments getMediaSegments() { if (segments == null) return null; return new MediaSegments(trackId, filePath, segments); } }