* Allow FFmpegFrameGrabber to use accelerated decoders with videoCodecName and audioCodecName properties (pull #948)

Author: saudet

CHANGELOG.md

@@ -1,4 +1,5 @@
 
+ * Allow `FFmpegFrameGrabber` to use accelerated decoders with `videoCodecName` and `audioCodecName` properties ([pull #948](https://github.com/bytedeco/javacv/pull/948))
  * Add new `KazemiFacemarkExample` and `LBFFacemarkExampleWithVideo` samples ([pull #1030](https://github.com/bytedeco/javacv/pull/1030))
  * Expose `apiPreference` constructor argument of `VideoCapture` to `OpenCVFrameGrabber` ([pull #1025](https://github.com/bytedeco/javacv/pull/1025))
  * Add `LeptonicaFrameConverter` to easily but efficiently pass image data to Tesseract ([issue bytedeco/javacpp-presets#224](https://github.com/bytedeco/javacpp-presets/issues/224))

src/main/java/org/bytedeco/javacv/FFmpegFrameGrabber.java

@@ -792,7 +792,10 @@ void startUnsafe() throws Exception {
 
         if (video_st != null) {
             // Find the decoder for the video stream
-            AVCodec codec = avcodec_find_decoder(video_par.codec_id());
+            AVCodec codec = avcodec_find_decoder_by_name(videoCodecName);
+            if (codec == null) {
+                codec = avcodec_find_decoder(video_par.codec_id());
+            }
             if (codec == null) {
                 throw new Exception("avcodec_find_decoder() error: Unsupported video format or codec not found: " + video_par.codec_id() + ".");
             }
@@ -836,7 +839,10 @@ void startUnsafe() throws Exception {
 
         if (audio_st != null) {
             // Find the decoder for the audio stream
-            AVCodec codec = avcodec_find_decoder(audio_par.codec_id());
+            AVCodec codec = avcodec_find_decoder_by_name(audioCodecName);
+            if (codec == null) {
+                codec = avcodec_find_decoder(audio_par.codec_id());
+            }
             if (codec == null) {
                 throw new Exception("avcodec_find_decoder() error: Unsupported audio format or codec not found: " + audio_par.codec_id() + ".");
             }

src/main/java/org/bytedeco/javacv/FrameGrabber.java

@@ -178,7 +178,7 @@ public static enum SampleMode {
             SENSOR_PATTERN_BGGR = (1L << 32) | 1;
 
     protected int videoStream = -1, audioStream = -1;
-    protected String format = null;
+    protected String format = null, videoCodecName = null, audioCodecName = null;
     protected int imageWidth = 0, imageHeight = 0, audioChannels = 0;
     protected ImageMode imageMode = ImageMode.COLOR;
     protected long sensorPattern = -1L;
@@ -223,6 +223,20 @@ public void setFormat(String format) {
         this.format = format;
     }
 
+    public String getVideoCodecName() {
+        return videoCodecName;
+    }
+    public void setVideoCodecName(String videoCodecName) {
+        this.videoCodecName = videoCodecName;
+    }
+
+    public String getAudioCodecName() {
+        return audioCodecName;
+    }
+    public void setAudioCodecName(String audioCodecName) {
+        this.audioCodecName = audioCodecName;
+    }
+
     public int getImageWidth() {
         return imageWidth;
     }