Fix recorded video rotation

app/proguard-rules.pro

@@ -25,3 +25,7 @@
 -keepclassmembers class sushi.hardcore.droidfs.explorers.ExplorerElement {
     static sushi.hardcore.droidfs.explorers.ExplorerElement new(...);
 }
+-keepclassmembers class sushi.hardcore.droidfs.video_recording.MediaMuxer {
+    void writePacket(byte[]);
+    void seek(long);
+}

app/src/main/java/sushi/hardcore/droidfs/video_recording/MediaMuxer.kt

@@ -6,7 +6,7 @@ import java.nio.ByteBuffer
 
 class MediaMuxer(val writer: SeekableWriter) {
     external fun allocContext(): Long
-    external fun addVideoTrack(formatContext: Long, bitrate: Int, width: Int, height: Int): Int
+    external fun addVideoTrack(formatContext: Long, bitrate: Int, width: Int, height: Int, orientationHint: Int): Int
     external fun addAudioTrack(formatContext: Long, bitrate: Int, sampleRate: Int, channelCount: Int): Int
     external fun writeHeaders(formatContext: Long): Int
     external fun writePacket(formatContext: Long, buffer: ByteArray, pts: Long, streamIndex: Int, isKeyFrame: Boolean)
@@ -20,6 +20,7 @@ class MediaMuxer(val writer: SeekableWriter) {
 
     var formatContext: Long?
 
+    var orientationHint = 0
     var realVideoTrackIndex: Int? = null
     var audioFrameSize: Int? = null
     var firstPts: Long? = null
@@ -63,7 +64,8 @@ class MediaMuxer(val writer: SeekableWriter) {
                 formatContext!!,
                 bitrate,
                 format.getInteger("width"),
-                format.getInteger("height")
+                format.getInteger("height"),
+                orientationHint
             )
             VIDEO_TRACK_INDEX
         }

app/src/main/java/sushi/hardcore/droidfs/video_recording/VideoCapture.java

@@ -464,6 +464,7 @@ public final class VideoCapture extends UseCase {
 
         synchronized (mMuxerLock) {
             mMuxer = new MediaMuxer(outputFileOptions.mWriter);
+            mMuxer.setOrientationHint(getRelativeRotation(attachedCamera));
         }
 
         mEndOfVideoStreamSignal.set(false);

app/src/main/native/libmux.c

@@ -1,6 +1,7 @@
 #include <libavformat/avformat.h>
 #include <libavcodec/avcodec.h>
 #include <libavutil/channel_layout.h>
+#include <libavutil/display.h>
 #include <jni.h>
 
 const size_t BUFF_SIZE = 4096;
@@ -68,14 +69,19 @@ Java_sushi_hardcore_droidfs_video_1recording_MediaMuxer_addAudioTrack(JNIEnv *en
 }
 
 JNIEXPORT jint JNICALL
-Java_sushi_hardcore_droidfs_video_1recording_MediaMuxer_addVideoTrack(JNIEnv *env, jobject thiz, jlong format_context, jint bitrate, jint width,
-                                                     jint height) {
+Java_sushi_hardcore_droidfs_video_1recording_MediaMuxer_addVideoTrack(JNIEnv *env, jobject thiz,
+                                                                      jlong format_context,
+                                                                      jint bitrate, jint width,
+                                                                      jint height,
+                                                                      jint orientation_hint) {
     AVStream* stream = avformat_new_stream((AVFormatContext *) format_context, NULL);
     stream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
     stream->codecpar->codec_id = AV_CODEC_ID_H264;
     stream->codecpar->bit_rate = bitrate;
     stream->codecpar->width = width;
     stream->codecpar->height = height;
+    uint8_t* matrix = av_stream_new_side_data(stream, AV_PKT_DATA_DISPLAYMATRIX, sizeof(int32_t) * 9);
+    av_display_rotation_set((int32_t *) matrix, orientation_hint);
     return stream->index;
 }
 

build.gradle

@@ -6,7 +6,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.0.2'
+        classpath 'com.android.tools.build:gradle:7.0.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }