Modification of SPS VUI params for low-latency

alexeyvasilyev · Nov 14, 2024 · c8b16c2 · c8b16c2
1 parent 41b30be
commit c8b16c2
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Showing 3 changed files with 28 additions and 11 deletions.
diff --git a/app/build.gradle b/app/build.gradle
@@ -46,7 +46,7 @@ dependencies {
     implementation 'androidx.constraintlayout:constraintlayout:2.2.0'
     implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
 
-    def androidx_navigation_version = '2.8.3'
+    def androidx_navigation_version = '2.8.4'
     implementation "androidx.navigation:navigation-fragment-ktx:$androidx_navigation_version"
     implementation "androidx.navigation:navigation-ui-ktx:$androidx_navigation_version"
     implementation "androidx.navigation:navigation-fragment-ktx:$androidx_navigation_version"

diff --git a/build.gradle b/build.gradle
@@ -4,8 +4,8 @@ buildscript {
   ext.compile_sdk_version = 35
   ext.min_sdk_version = 24
   ext.target_sdk_version = 35
-  ext.project_version_code = 520
-  ext.project_version_name = '5.2.0'
+  ext.project_version_code = 521
+  ext.project_version_name = '5.2.1'
 
   repositories {
     google()

diff --git a/library-client-rtsp/src/main/java/com/alexvas/rtsp/widget/RtspProcessor.kt b/library-client-rtsp/src/main/java/com/alexvas/rtsp/widget/RtspProcessor.kt
@@ -21,6 +21,7 @@ import com.alexvas.rtsp.codec.VideoFrameQueue
 import com.alexvas.utils.NetUtils
 import com.alexvas.utils.VideoCodecUtils
 import org.jcodec.codecs.h264.io.model.SeqParameterSet
+import org.jcodec.codecs.h264.io.model.VUIParameters
 import java.net.Socket
 import java.nio.ByteBuffer
 import java.util.concurrent.atomic.AtomicBoolean
@@ -494,14 +495,30 @@ class RtspProcessor(
             // Read SPS frame
             val spsSet = SeqParameterSet.read(spsBufferReadFrame)
 
-            // SPS frame already has num_ref_frames set to 0. Return original frame.
-            if (spsSet.numRefFrames == 0)
-                return frame
-
-            // Change SPS frame
-            if (debug)
-                Log.d(TAG, "Changed SPS num_ref_frames ${spsSet.numRefFrames} -> 0")
-            spsSet.numRefFrames = 0
+            // adding VUI might decrease latency for some streams, if max_dec_frame_buffering is set properly
+            // https://community.intel.com/t5/Media-Intel-oneAPI-Video/h-264-decoder-gives-two-frames-latency-while-decoding-a-stream/td-p/1099694
+            // https://github.com/Consti10/LiveVideo10ms/blob/master/VideoCore/src/main/cpp/NALU/H26X.hpp
+            fun modifyVui() {
+//                spsSet.vuiParams = VUIParameters()
+                spsSet.vuiParams.apply {
+//                    videoSignalTypePresentFlag = true
+//                    videoFormat = 5
+//                    colourDescriptionPresentFlag = true
+//                    matrixCoefficients = 5
+//                    timingInfoPresentFlag = true
+//                    numUnitsInTick = 1
+//                    timeScale = 120
+//                    fixedFrameRateFlag = true
+                    bitstreamRestriction = VUIParameters.BitstreamRestriction().apply {
+//                        motionVectorsOverPicBoundariesFlag = true
+//                        log2MaxMvLengthHorizontal = 16
+//                        log2MaxMvLengthVertical = 16
+                        maxDecFrameBuffering = 1
+                        numReorderFrames = 0
+                    }
+                }
+            }
+            modifyVui()
 
             // Write SPS frame
             spsBufferWriteFrame.rewind()