rate control not quite working but committing anyway due to format change

assets/disk0/tvdos/bin/playtev.js

@@ -201,8 +201,20 @@ try {
                 sys.memcpy(CURRENT_RGB_ADDR, PREV_RGB_ADDR, FRAME_PIXELS * 3)
 
             } else if (packetType == TEV_PACKET_IFRAME || packetType == TEV_PACKET_PFRAME) {
-                // Video frame packet
+                // Video frame packet (always includes rate control factor)
                 let payloadLen = seqread.readInt()
+                
+                // Always read rate control factor (4 bytes, little-endian float)
+                let rateFactorBytes = seqread.readBytes(4)
+                let view = new DataView(new ArrayBuffer(4))
+                for (let i = 0; i < 4; i++) {
+                    view.setUint8(i, sys.peek(rateFactorBytes + i))
+                }
+                let rateControlFactor = view.getFloat32(0, true) // true = little-endian
+                //serial.println(`rateControlFactor = ${rateControlFactor}`)
+                sys.free(rateFactorBytes)
+                payloadLen -= 4 // Subtract rate factor size from payload
+                
                 let compressedPtr = seqread.readBytes(payloadLen)
                 updateDataRateBin(payloadLen)
 
@@ -232,9 +244,9 @@ try {
                     continue
                 }
 
-                // Hardware-accelerated TEV YCoCg-R decoding to RGB buffers
+                // Hardware-accelerated TEV YCoCg-R decoding to RGB buffers (with rate control factor)
                 try {
-                    graphics.tevDecode(blockDataPtr, CURRENT_RGB_ADDR, PREV_RGB_ADDR, width, height, quality, debugMotionVectors)
+                    graphics.tevDecode(blockDataPtr, CURRENT_RGB_ADDR, PREV_RGB_ADDR, width, height, quality, debugMotionVectors, rateControlFactor)
 
                     // Upload RGB buffer to display framebuffer with dithering
                     graphics.uploadRGBToFramebuffer(CURRENT_RGB_ADDR, DISPLAY_RG_ADDR, DISPLAY_BA_ADDR,

terranmon.txt

@@ -678,6 +678,12 @@ Created by Claude on 2025-08-17
 TEV is a modern video codec optimized for TSVM's 4096-color hardware, featuring
 DCT-based compression, motion compensation, and efficient temporal coding.
 
+## Version History
+- Version 2.0: YCoCg-R 4:2:0 with 16x16/8x8 DCT blocks
+- Version 2.1: Added Rate Control Factor to all video packets (breaking change)
+  * Enables bitrate-constrained encoding alongside quality modes
+  * All video frames now include 4-byte rate control factor after payload size
+
 # File Structure
 \x1F T S V M T E V
 [HEADER]
@@ -694,7 +700,7 @@ DCT-based compression, motion compensation, and efficient temporal coding.
     uint16 Height: video height in pixels  
     uint16 FPS: frames per second
     uint32 Total Frames: number of video frames
-    uint8  Quality: quantization quality (0-7, higher = better)
+    uint8  Quality: quantization quality (0-4, higher = better)
     byte[5] Reserved
 
 ## Packet Types
@@ -705,7 +711,8 @@ DCT-based compression, motion compensation, and efficient temporal coding.
 
 ## Video Packet Structure
     uint8  Packet Type
-    uint32 Compressed Size
+    uint32 Compressed Size (includes rate control factor size)
+    float  Rate Control Factor (4 bytes, little-endian)
     *      Gzip-compressed Block Data
 
 ## Block Data (per 16x16 block)
@@ -722,11 +729,19 @@ DCT-based compression, motion compensation, and efficient temporal coding.
     int16[64]  DCT Coefficients Cg (subsampled by two, aggressively quantised)
         For SKIP and MOTION mode, DCT coefficients are filled with zero
 
-## DCT Quantization
+## DCT Quantization and Rate Control
 TEV uses 8 quality levels (0=lowest, 7=highest) with progressive quantization
 tables optimized for perceptual quality. DC coefficients use fixed quantizer
 of 8, while AC coefficients are quantized according to quality tables.
 
+### Rate Control Factor
+Each video frame includes a Rate Control Factor that modifies quantization:
+- Quality mode: Factor = 1.0 (fixed quantization based on quality level)
+- Bitrate mode: Factor varies per frame based on content complexity and target bitrate
+- Encoder: quantized_coeff = dct_coeff / (base_quant * rate_factor)  
+- Decoder: dequantized_coeff = quantized_coeff * (base_quant / rate_factor)
+- Optimization: When factor ≈ 1.0 (0.999-1.001), decoder uses original tables
+
 ## Motion Compensation
 - Search range: ±8 pixels
 - Sub-pixel precision: 1/4 pixel (again, integer precision for now)

tsvm_core/src/net/torvald/tsvm/GraphicsJSR223Delegate.kt

@@ -1567,7 +1567,8 @@ class GraphicsJSR223Delegate(private val vm: VM) {
      * @param frameCounter Frame counter for temporal patterns
      */
     fun tevDecode(blockDataPtr: Long, currentRGBAddr: Long, prevRGBAddr: Long,
-                  width: Int, height: Int, quality: Int, debugMotionVectors: Boolean = false) {
+                  width: Int, height: Int, quality: Int, debugMotionVectors: Boolean = false, 
+                  rateControlFactor: Float = 1.0f) {
 
         val blocksX = (width + 15) / 16  // 16x16 blocks now
         val blocksY = (height + 15) / 16
@@ -1576,9 +1577,22 @@ class GraphicsJSR223Delegate(private val vm: VM) {
         val quantCOmult = QUANT_MULT_CO[quality]
         val quantCGmult = QUANT_MULT_CG[quality]
 
-        val quantTableY = QUANT_TABLE_Y.map { it * quantYmult }.toIntArray()
-        val quantTableCo = QUANT_TABLE_C.map { it * quantCOmult }.toIntArray()
-        val quantTableCg = QUANT_TABLE_C.map { it * quantCGmult }.toIntArray()
+        // Apply rate control factor to quantization tables (if not ~1.0, skip optimization)
+        val quantTableY = if (rateControlFactor in 0.999f..1.001f) {
+            QUANT_TABLE_Y.map { it * quantYmult }.toIntArray()
+        } else {
+            QUANT_TABLE_Y.map { (it * quantYmult * rateControlFactor).toInt() }.toIntArray()
+        }
+        val quantTableCo = if (rateControlFactor in 0.999f..1.001f) {
+            QUANT_TABLE_C.map { it * quantCOmult }.toIntArray()
+        } else {
+            QUANT_TABLE_C.map { (it * quantCOmult * rateControlFactor).toInt() }.toIntArray()
+        }
+        val quantTableCg = if (rateControlFactor in 0.999f..1.001f) {
+            QUANT_TABLE_C.map { it * quantCGmult }.toIntArray()
+        } else {
+            QUANT_TABLE_C.map { (it * quantCGmult * rateControlFactor).toInt() }.toIntArray()
+        }
         
         var readPtr = blockDataPtr