From 07f1e4fd9895491229f22480aa1b23634d9d0ab4 Mon Sep 17 00:00:00 2001
From: Samuel Audet <samuel.audet@gmail.com>
Date: Wed, 29 Apr 2015 15:02:03 +0900
Subject: [PATCH]  * Add the ability to specify from which video and audio
 streams `FFmpegFrameGrabber` should grab from (issue #135)

---
 CHANGELOG.md                                      |  1 +
 .../org/bytedeco/javacv/FFmpegFrameGrabber.java   |  9 +++++----
 .../java/org/bytedeco/javacv/FrameGrabber.java    | 15 +++++++++++++++
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58a0db4c..3032b6f7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 
+ * Add the ability to specify from which video and audio streams `FFmpegFrameGrabber` should grab from ([issue #135](https://github.com/bytedeco/javacv/issues/135))
  * Fix `Java2DFrameConverter` when used with `BufferedImage.TYPE_INT_RGB` or other types based on `int`
  * Add new `WebcamAndMicrophoneCapture` sample ([pull #131](https://github.com/bytedeco/javacv/pull/131))
  * Add `aspectRatio` property to `FrameGrabber` and `FrameRecorder`, to be able to use pixel aspect ratios other than 1.0 ([issue #90](https://github.com/bytedeco/javacv/issues/90))
diff --git a/src/main/java/org/bytedeco/javacv/FFmpegFrameGrabber.java b/src/main/java/org/bytedeco/javacv/FFmpegFrameGrabber.java
index f72a5806..f47269e7 100644
--- a/src/main/java/org/bytedeco/javacv/FFmpegFrameGrabber.java
+++ b/src/main/java/org/bytedeco/javacv/FFmpegFrameGrabber.java
@@ -413,23 +413,24 @@ public void startUnsafe() throws Exception {
         // Dump information about file onto standard error
         av_dump_format(oc, 0, filename, 0);
 
-        // Find the first video and audio stream
+        // Find the first video and audio stream, unless the user specified otherwise
         video_st = audio_st = null;
         int nb_streams = oc.nb_streams();
         for (int i = 0; i < nb_streams; i++) {
             AVStream st = oc.streams(i);
             // Get a pointer to the codec context for the video or audio stream
             AVCodecContext c = st.codec();
-            if (video_st == null && c.codec_type() == AVMEDIA_TYPE_VIDEO) {
+            if (video_st == null && c.codec_type() == AVMEDIA_TYPE_VIDEO && (videoStream < 0 || videoStream == i)) {
                 video_st = st;
                 video_c = c;
-            } else if (audio_st == null && c.codec_type() == AVMEDIA_TYPE_AUDIO) {
+            } else if (audio_st == null && c.codec_type() == AVMEDIA_TYPE_AUDIO && (audioStream < 0 || audioStream == i)) {
                 audio_st = st;
                 audio_c = c;
             }
         }
         if (video_st == null && audio_st == null) {
-            throw new Exception("Did not find a video or audio stream inside \"" + filename + "\".");
+            throw new Exception("Did not find a video or audio stream inside \"" + filename
+                    + "\" for videoStream == " + videoStream + " and audioStream == " + audioStream + ".");
         }
 
         if (video_st != null) {
diff --git a/src/main/java/org/bytedeco/javacv/FrameGrabber.java b/src/main/java/org/bytedeco/javacv/FrameGrabber.java
index af1e37c2..6aea5a58 100644
--- a/src/main/java/org/bytedeco/javacv/FrameGrabber.java
+++ b/src/main/java/org/bytedeco/javacv/FrameGrabber.java
@@ -164,6 +164,7 @@ public static enum ImageMode {
             SENSOR_PATTERN_GRBG = 1,
             SENSOR_PATTERN_BGGR = (1L << 32) | 1;
 
+    protected int videoStream = -1, audioStream = -1;
     protected String format = null;
     protected int imageWidth = 0, imageHeight = 0, audioChannels = 0;
     protected ImageMode imageMode = ImageMode.COLOR;
@@ -181,6 +182,20 @@ public static enum ImageMode {
     protected int frameNumber = 0;
     protected long timestamp = 0;
 
+    public int getVideoStream() {
+        return videoStream;
+    }
+    public void setVideoStream(int videoStream) {
+        this.videoStream = videoStream;
+    }
+
+    public int getAudioStream() {
+        return audioStream;
+    }
+    public void setAudioStream(int audioStream) {
+        this.audioStream = audioStream;
+    }
+
     public String getFormat() {
         return format;
     }