tav player: seek and pause

assets/disk0/tvdos/bin/playtav.js

@@ -470,6 +470,75 @@ let decoderDbgInfo = {}
 
 let cueElements = []
 let currentCueIndex = -1  // Track current cue position
+let iframePositions = []  // Track I-frame positions for seeking: [{offset, frameNum}]
+
+// Function to find nearest I-frame before or at target frame
+function findNearestIframe(targetFrame) {
+    if (iframePositions.length === 0) return null
+
+    // Find the largest I-frame position <= targetFrame
+    let result = null
+    for (let i = iframePositions.length - 1; i >= 0; i--) {
+        if (iframePositions[i].frameNum <= targetFrame) {
+            result = iframePositions[i]
+            break
+        }
+    }
+
+    // If targetFrame is before first I-frame, return first I-frame
+    return result || iframePositions[0]
+}
+
+// Function to scan forward and find next I-frame at or after target frame
+function scanForwardToIframe(targetFrame, currentPos) {
+    // Save current position
+    let savedPos = seqread.getReadCount()
+
+    try {
+        let scanFrameCount = frameCount
+
+        // Scan forward through packets
+        while (seqread.getReadCount() < FILE_LENGTH) {
+            let packetPos = seqread.getReadCount()
+            let pType = seqread.readOneByte()
+
+            // Handle sync packets (increment frame counter)
+            if (pType === TAV_PACKET_SYNC || pType === TAV_PACKET_SYNC_NTSC) {
+                if (pType === TAV_PACKET_SYNC) {
+                    scanFrameCount++
+                }
+                continue
+            }
+
+            // Found I-frame at or after target?
+            if (pType === TAV_PACKET_IFRAME && scanFrameCount >= targetFrame) {
+                // Record this I-frame position for future use
+                iframePositions.push({offset: packetPos, frameNum: scanFrameCount})
+                return {offset: packetPos, frameNum: scanFrameCount}
+            }
+
+            // Skip over packet payload (all non-sync packets have uint32 size)
+            if (pType !== TAV_PACKET_SYNC && pType !== TAV_PACKET_SYNC_NTSC && pType !== TAV_FILE_HEADER_FIRST) {
+                let payloadSize = seqread.readInt()
+                seqread.skip(payloadSize)
+            } else if (pType === TAV_FILE_HEADER_FIRST) {
+                // Hit next file header, stop scanning
+                break
+            }
+        }
+
+        // Didn't find I-frame, restore position
+        return null
+
+    } catch (e) {
+        // Error or EOF during scan
+        serial.printerr(`Scan error: ${e}`)
+        return null
+    } finally {
+        // Restore original position
+        seqread.seek(savedPos)
+    }
+}
 
 // Function to try reading next TAV file header at current position
 function tryReadNextTAVHeader() {
@@ -624,6 +693,7 @@ function tryReadNextTAVHeader() {
 
 let lastKey = 0
 let skipped = false
+let paused = false
 
 // Playback loop - properly adapted from TEV with multi-file support
 try {
@@ -642,6 +712,16 @@ try {
                     stopPlay = true
                     break
                 }
+                else if (keyCode == 62) { // SPACE - pause/resume
+                    paused = !paused
+                    if (paused) {
+                        audio.stop(0)
+                        serial.println(`Paused at frame ${frameCount}`)
+                    } else {
+                        audio.play(0)
+                        serial.println(`Resumed`)
+                    }
+                }
                 else if (keyCode == 19 && cueElements.length > 0) { // Up arrow - previous cue
                     currentCueIndex = (currentCueIndex <= 0) ? cueElements.length - 1 : currentCueIndex - 1
                     let cue = cueElements[currentCueIndex]
@@ -653,6 +733,10 @@ try {
                         akku = FRAME_TIME
                         akku2 = 0.0
                         audio.purgeQueue(0)
+                        if (paused) {
+                            audio.play(0)
+                            audio.stop(0)
+                        }
                         skipped = true
                     }
                 }
@@ -667,17 +751,70 @@ try {
                         akku = FRAME_TIME
                         akku2 = 0.0
                         audio.purgeQueue(0)
+                        if (paused) {
+                            audio.play(0)
+                            audio.stop(0)
+                        }
                         skipped = true
                     }
                 }
+                else if (keyCode == 21) { // Left arrow - seek back 5.5s
+                    let targetFrame = Math.max(0, frameCount - Math.floor(header.fps * 5.5))
+                    let seekTarget = findNearestIframe(targetFrame)
+
+                    if (seekTarget) {
+                        serial.println(`Seeking back to frame ${seekTarget.frameNum} (offset ${seekTarget.offset})`)
+                        seqread.seek(seekTarget.offset)
+                        frameCount = seekTarget.frameNum
+                        akku = FRAME_TIME
+                        akku2 -= 5.5
+                        audio.purgeQueue(0)
+                        if (paused) {
+                            audio.play(0)
+                            audio.stop(0)
+                        }
+                        skipped = true
+                    }
+                }
+                else if (keyCode == 22) { // Right arrow - seek forward 5s
+                    let targetFrame = Math.min(header.totalFrames - 1, frameCount + Math.floor(header.fps * 5.0))
+
+                    // Try to find in already-decoded I-frames first
+                    let seekTarget = findNearestIframe(targetFrame)
+
+                    // If not found or behind current position, scan forward
+                    if (!seekTarget || seekTarget.frameNum <= frameCount) {
+                        serial.println(`Scanning forward for I-frame near frame ${targetFrame}...`)
+                        seekTarget = scanForwardToIframe(targetFrame, seqread.getReadCount())
+                    }
+
+                    if (seekTarget && seekTarget.frameNum > frameCount) {
+                        serial.println(`Seeking forward to frame ${seekTarget.frameNum} (offset ${seekTarget.offset})`)
+                        seqread.seek(seekTarget.offset)
+                        frameCount = seekTarget.frameNum
+                        akku = FRAME_TIME
+                        akku2 += 5.0
+                        audio.purgeQueue(0)
+                        if (paused) {
+                            audio.play(0)
+                            audio.stop(0)
+                        }
+                        skipped = true
+                    } else if (!seekTarget) {
+                        serial.println(`No I-frame found ahead`)
+                    }
+                }
             }
 
             lastKey = keyCode
         }
 
         if (akku >= FRAME_TIME) {
-            // Read packet header
+            // When paused, just reset accumulator and skip frame processing
-            var packetType = seqread.readOneByte()
+            if (!paused) {
+                // Read packet header (record position before reading for I-frame tracking)
+                let packetOffset = seqread.getReadCount()
+                var packetType = seqread.readOneByte()
 
 //            serial.println(`Packet ${packetType} at offset ${seqread.getReadCount() - 1}`)
 
@@ -733,6 +870,11 @@ try {
 
             }
             else if (packetType === TAV_PACKET_IFRAME || packetType === TAV_PACKET_PFRAME) {
+                // Record I-frame position for seeking
+                if (packetType === TAV_PACKET_IFRAME) {
+                    iframePositions.push({offset: packetOffset, frameNum: frameCount})
+                }
+
                 // Video packet
                 const compressedSize = seqread.readInt()
 
@@ -870,11 +1012,14 @@ try {
                 println(`Unknown packet type: 0x${packetType.toString(16)}`)
                 break
             }
+            } // end of !paused block
         }
 
         let t2 = sys.nanoTime()
-        akku += (t2 - t1) / 1000000000.0
+        if (!paused) {
-        akku2 += (t2 - t1) / 1000000000.0
+            akku += (t2 - t1) / 1000000000.0
+            akku2 += (t2 - t1) / 1000000000.0
+        }
 
         // Simple progress display
         if (interactive) {
@@ -899,7 +1044,7 @@ try {
                 fileOrd: (cueElements.length > 0) ? currentCueIndex+1 : currentFileIndex,
                 resolution: `${header.width}x${header.height}${(isInterlaced) ? 'i' : ''}`,
                 colourSpace: header.version % 2 == 0 ? "ICtCp" : "YCoCg",
-                currentStatus: 1
+                currentStatus: paused ? 2 : 1  // 2 = paused, 1 = playing
             }
             gui.printBottomBar(guiStatus)
             gui.printTopBar(guiStatus, 1)

assets/disk0/tvdos/bin/playtev.js

@@ -659,7 +659,7 @@ try {
                             // For interlaced: decode current frame into currentFieldAddr
                             // For display: use prevFieldAddr as current, currentFieldAddr as next
                             graphics.tevDecode(blockDataPtr, nextFieldAddr, currentFieldAddr, width, decodingHeight, qualityY, qualityCo, qualityCg, trueFrameCount, debugMotionVectors, version, enableDeblocking, enableBoundaryAwareDecoding)
-                            graphics.tevDeinterlace(trueFrameCount, width, decodingHeight, prevFieldAddr, currentFieldAddr, nextFieldAddr, CURRENT_RGB_ADDR, deinterlaceAlgorithm)
+                            graphics.tevDeinterlace(trueFrameCount + 1, width, decodingHeight, prevFieldAddr, currentFieldAddr, nextFieldAddr, CURRENT_RGB_ADDR, deinterlaceAlgorithm)
 
                             // Rotate field buffers for next frame: NEXT -> CURRENT -> PREV
                             rotateFieldBuffers()

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

@@ -4683,8 +4683,8 @@ class GraphicsJSR223Delegate(private val vm: VM) {
                 val random = java.util.Random()
                 for (i in 0 until coeffCount) {
                     yTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
-                    coTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
+//                    coTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
-                    cgTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
+//                    cgTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
                 }
             }
 
@@ -4749,8 +4749,8 @@ class GraphicsJSR223Delegate(private val vm: VM) {
                 val random = java.util.Random()
                 for (i in 0 until coeffCount) {
                     yTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
-                    coTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
+//                    coTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
-                    cgTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
+//                    cgTile[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
                 }
             }
 
@@ -5331,8 +5331,8 @@ class GraphicsJSR223Delegate(private val vm: VM) {
             val random = java.util.Random()
             for (i in 0 until coeffCount) {
                 currentY[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
-                currentCo[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
+//                currentCo[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
-                currentCg[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
+//                currentCg[i] += (random.nextInt(filmGrainLevel * 2 + 1) - filmGrainLevel).toFloat()
             }
         }
 

video_encoder/encoder_tav.c

@@ -3433,6 +3433,83 @@ static int detect_still_frame(tav_encoder_t *enc) {
     return (changed_pixels == 0);
 }
 
+// Detect still frames by comparing quantised DWT coefficients
+// Returns 1 if quantised coefficients are identical (frame is truly still), 0 otherwise
+// Benefits: quality-aware (lower quality = more SKIP frames), pure integer math
+// DISABLED - should work in theory, not actually
+static int detect_still_frame_dwt(tav_encoder_t *enc) {
+    if (!enc->previous_coeffs_allocated || enc->intra_only) {
+        return 0; // No previous coefficients to compare or intra-only mode
+    }
+
+    // Only compare against I-frames to avoid DELTA quantization drift
+    // previous_coeffs are updated by DELTA frames with reconstructed values that accumulate error
+    if (enc->last_frame_packet_type != TAV_PACKET_IFRAME) {
+        return 0; // Must compare against clean I-frame, not DELTA reconstruction
+    }
+
+    // Get current quantisers (use adjusted quantiser from bitrate control if applicable)
+    int qY = enc->bitrate_mode ? quantiser_float_to_int_dithered(enc) : enc->quantiser_y;
+    int this_frame_qY = QLUT[qY];
+    int this_frame_qCo = QLUT[enc->quantiser_co];
+    int this_frame_qCg = QLUT[enc->quantiser_cg];
+
+    // Coefficient count (monoblock mode)
+    const int coeff_count = enc->width * enc->height;
+
+    // Quantise current DWT coefficients
+    int16_t *quantised_y = enc->reusable_quantised_y;
+    int16_t *quantised_co = enc->reusable_quantised_co;
+    int16_t *quantised_cg = enc->reusable_quantised_cg;
+
+    if (enc->perceptual_tuning) {
+        quantise_dwt_coefficients_perceptual_per_coeff(enc, enc->current_dwt_y, quantised_y, coeff_count, this_frame_qY, enc->width, enc->height, enc->decomp_levels, 0, enc->frame_count);
+        quantise_dwt_coefficients_perceptual_per_coeff(enc, enc->current_dwt_co, quantised_co, coeff_count, this_frame_qCo, enc->width, enc->height, enc->decomp_levels, 1, enc->frame_count);
+        quantise_dwt_coefficients_perceptual_per_coeff(enc, enc->current_dwt_cg, quantised_cg, coeff_count, this_frame_qCg, enc->width, enc->height, enc->decomp_levels, 1, enc->frame_count);
+    } else {
+        quantise_dwt_coefficients(enc->current_dwt_y, quantised_y, coeff_count, this_frame_qY, enc->dead_zone_threshold, enc->width, enc->height, enc->decomp_levels, 0);
+        quantise_dwt_coefficients(enc->current_dwt_co, quantised_co, coeff_count, this_frame_qCo, enc->dead_zone_threshold, enc->width, enc->height, enc->decomp_levels, 1);
+        quantise_dwt_coefficients(enc->current_dwt_cg, quantised_cg, coeff_count, this_frame_qCg, enc->dead_zone_threshold, enc->width, enc->height, enc->decomp_levels, 1);
+    }
+
+    // Quantise previous DWT coefficients (stored from last I-frame)
+    int16_t *prev_quantised_y = malloc(coeff_count * sizeof(int16_t));
+    int16_t *prev_quantised_co = malloc(coeff_count * sizeof(int16_t));
+    int16_t *prev_quantised_cg = malloc(coeff_count * sizeof(int16_t));
+
+    if (enc->perceptual_tuning) {
+        quantise_dwt_coefficients_perceptual_per_coeff(enc, enc->previous_coeffs_y, prev_quantised_y, coeff_count, this_frame_qY, enc->width, enc->height, enc->decomp_levels, 0, enc->frame_count);
+        quantise_dwt_coefficients_perceptual_per_coeff(enc, enc->previous_coeffs_co, prev_quantised_co, coeff_count, this_frame_qCo, enc->width, enc->height, enc->decomp_levels, 1, enc->frame_count);
+        quantise_dwt_coefficients_perceptual_per_coeff(enc, enc->previous_coeffs_cg, prev_quantised_cg, coeff_count, this_frame_qCg, enc->width, enc->height, enc->decomp_levels, 1, enc->frame_count);
+    } else {
+        quantise_dwt_coefficients(enc->previous_coeffs_y, prev_quantised_y, coeff_count, this_frame_qY, enc->dead_zone_threshold, enc->width, enc->height, enc->decomp_levels, 0);
+        quantise_dwt_coefficients(enc->previous_coeffs_co, prev_quantised_co, coeff_count, this_frame_qCo, enc->dead_zone_threshold, enc->width, enc->height, enc->decomp_levels, 1);
+        quantise_dwt_coefficients(enc->previous_coeffs_cg, prev_quantised_cg, coeff_count, this_frame_qCg, enc->dead_zone_threshold, enc->width, enc->height, enc->decomp_levels, 1);
+    }
+
+    // Compare quantised coefficients - pure integer math
+    int diff_count = 0;
+    for (int i = 0; i < coeff_count; i++) {
+        if (quantised_y[i] != prev_quantised_y[i] ||
+            quantised_co[i] != prev_quantised_co[i] ||
+            quantised_cg[i] != prev_quantised_cg[i]) {
+            diff_count++;
+        }
+    }
+
+    free(prev_quantised_y);
+    free(prev_quantised_co);
+    free(prev_quantised_cg);
+
+    if (enc->verbose) {
+        printf("Still frame detection (DWT): %d/%d coeffs differ\n", diff_count, coeff_count);
+    }
+
+    // If all quantised coefficients match, frames are identical after compression
+    return (diff_count == 0);
+}
+
+
 // Main function
 int main(int argc, char *argv[]) {
     generate_random_filename(TEMP_AUDIO_FILE);
@@ -3892,18 +3969,14 @@ int main(int argc, char *argv[]) {
         int is_scene_change = detect_scene_change(enc);
         int is_time_keyframe = (frame_count % KEYFRAME_INTERVAL) == 0;
 
-        // Check if we can use SKIP mode
+        // Check if we can use SKIP mode (DWT coefficient-based detection)
         int is_still = detect_still_frame(enc);
         enc->is_still_frame_cached = is_still;  // Cache for use in compress_and_write_frame
 
-        // SKIP mode can be used if:
+        // SKIP mode can be used if frame is still (detect_still_frame_dwt already checks against I-frame)
-        // 1. Frame is still AND
+        // SKIP runs can continue as long as frames remain identical to the reference I-frame
-        // 2. Previous coeffs allocated AND
-        // 3. (Last frame was I-frame OR we're continuing a SKIP run)
         int in_skip_run = enc->used_skip_mode_last_frame;
-        int can_use_skip = is_still &&
+        int can_use_skip = is_still && enc->previous_coeffs_allocated;
-                          enc->previous_coeffs_allocated &&
-                          (enc->last_frame_packet_type == TAV_PACKET_IFRAME || in_skip_run);
 
         // During a SKIP run, suppress keyframe timer unless content changes enough to un-skip
         // Un-skip threshold is the negation of SKIP threshold: content must change to break the run