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terranmon.txt update
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minjaesong
@@ -759,10 +759,10 @@ note: metadata packets must precede any non-metadata packets
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int16[64] DCT Coefficients Cg (subsampled by two, aggressively quantised)
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For SKIP and MOTION mode, DCT coefficients are filled with zero
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## DCT Quantization and Rate Control
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TEV uses 5 quality levels (0=lowest, 4=highest) with progressive quantization
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## DCT Quantisation and Rate Control
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TEV uses 5 quality levels (0=lowest, 4=highest) with progressive quantisation
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tables optimized for perceptual quality. DC coefficients are encoded losslessly,
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while AC coefficients are quantized according to quality tables.
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while AC coefficients are quantised according to quality tables.
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### Rate Control Factor
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Each block includes a Rate Control Factor that modifies quality level for that specific block.
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@@ -940,17 +940,19 @@ transmission capability, and region-of-interest coding.
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## Packet Types
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0x10: I-frame (intra-coded frame)
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0x11: P-frame (delta-coded frame)
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0x12/13: Video channel 2 I/P-frame
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0x14/15: Video channel 3 I/P-frame
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0x16/17: Video channel 4 I/P-frame
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0x18/19: Video channel 5 I/P-frame
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0x1A/1B: Video channel 6 I/P-frame
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0x1C/1D: Video channel 7 I/P-frame
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0x1E: Video channel 8 I-frame
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0x1F: (prohibited)
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0x20: MP2 audio packet
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0x30: Subtitle in "Simple" format
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0x31: Subtitle in "Karaoke" format
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<multiplexed video>
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0x70/71: Video channel 2 I/P-frame
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0x72/73: Video channel 3 I/P-frame
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0x74/75: Video channel 4 I/P-frame
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0x76/77: Video channel 5 I/P-frame
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0x78/79: Video channel 6 I/P-frame
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0x7A/7B: Video channel 7 I/P-frame
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0x7C/7D: Video channel 8 I/P-frame
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0x7E/7F: Video channel 9 I/P-frame
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<Standard metadata payloads>
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(it's called "standard" because you're expected to just copy-paste the metadata bytes verbatim)
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0xE0: EXIF packet
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@@ -964,6 +966,22 @@ transmission capability, and region-of-interest coding.
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0xFE: NTSC sync packet (used by player to calculate exact framerate-wise performance)
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0xFF: Sync packet
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### Packet Precedence
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Before the first frame group:
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1. Standard metadata payloads
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Frame group:
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1. File packet (0x1F)
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2. Audio packets
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3. Subtitle packets
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4. Main video packets (0x10-0x1E)
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5. Multiplexed video packets (0x70-7F)
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6. Loop point packets
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After a frame group:
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1. Sync packet
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## Standard metadata payload packet structure
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uint8 0xE0/0xE1/0xE2/.../0xEF (see Packet Types section)
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uint32 Length of the payload
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@@ -982,10 +1000,9 @@ transmission capability, and region-of-interest coding.
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## Block Data (per frame)
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uint8 Mode: encoding mode
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0x00 = SKIP (copy from previous frame)
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0x01 = INTRA (DWT-coded)
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0x02 = DELTA (DWT delta)
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uint8 Quantiser override Y (uses exponential numeric system; stored with index bias of 1 (127->252, 255->4032); use 0 to disable overriding; shared with A channel)
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uint8 Quantiser override Y (uses exponential numeric system; stored with index bias of 1 (127->252, 255->4032); use 0 to disable overriding)
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uint8 Quantiser override Co (uses exponential numeric system; stored with index bias of 1 (127->252, 255->4032); use 0 to disable overriding)
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uint8 Quantiser override Cg (uses exponential numeric system; stored with index bias of 1 (127->252, 255->4032); use 0 to disable overriding)
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- note: quantiser overrides are always present regardless of the channel layout
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@@ -1014,23 +1031,10 @@ transmission capability, and region-of-interest coding.
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- Bit = 0: coefficient is zero
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#### Compression Benefits
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- **Sparsity exploitation**: Typically 85-95% zeros in quantized DWT coefficients
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- **Sparsity exploitation**: Typically 85-95% zeros in quantised DWT coefficients
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- **Cross-channel patterns**: Concatenated maps allow Zstd to find patterns across similar significance maps
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- **Overall improvement**: 16-18% compression improvement before Zstd compression
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### DWT Coefficient Structure (per tile)
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For each decomposition level L (from highest to lowest):
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uint16 LL_size: size of LL subband coefficients
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uint16 LH_size: size of LH subband coefficients
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uint16 HL_size: size of HL subband coefficients
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uint16 HH_size: size of HH subband coefficients
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int16[] LL_coeffs: quantized LL subband (low-low frequencies)
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int16[] LH_coeffs: quantized LH subband (low-high frequencies)
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int16[] HL_coeffs: quantized HL subband (high-low frequencies)
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int16[] HH_coeffs: quantized HH subband (high-high frequencies)
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## DWT Implementation Details
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### Wavelet Filters
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@@ -1039,16 +1043,16 @@ transmission capability, and region-of-interest coding.
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* Synthesis: Low-pass [1/4, 1/2, 1/4], High-pass [-1/16, -1/8, 3/8, -1/8, -1/16]
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- 9/7 Irreversible Filter (higher compression):
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* Analysis: Daubechies 9/7 coefficients optimized for image compression
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* Analysis: CDF 9/7 coefficients optimized for image compression
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* Provides better energy compaction than 5/3 but lossy reconstruction
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### Quantization Strategy
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### Quantisation Strategy
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#### Uniform Quantization (Versions 3-4)
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Traditional approach using same quantization factor for all DWT subbands within each channel.
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#### Uniform Quantisation (Versions 3-4)
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Traditional approach using same quantisation factor for all DWT subbands within each channel.
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#### Perceptual Quantization (Versions 5-6, Default)
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TAV versions 5 and 6 implement Human Visual System (HVS) optimized quantization with
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#### Perceptual Quantisation (Versions 5-6, Default)
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TAV versions 5 and 6 implement Human Visual System (HVS) optimized quantisation with
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frequency-aware subband weighting for superior visual quality:
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Anisotropic quantisation is applied for both Luma and Chroma channels to preserve horizontal details.
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@@ -1056,7 +1060,7 @@ The anisotropic quantisation is the innovative upgrade to the traditional field-
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chroma subsampling.
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This perceptual approach allocates more bits to visually important low-frequency
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details while aggressively quantizing high-frequency noise, resulting in superior
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details while aggressively quantising high-frequency noise, resulting in superior
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visual quality at equivalent bitrates.
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## Colour Space
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@@ -1072,8 +1076,8 @@ TAV supports two colour spaces:
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- Ct: Chroma tritanopia
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- Cp: Chroma protanopia
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Perceptual versions (5-6) apply HVS-optimized quantization weights per channel,
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while uniform versions (3-4) use consistent quantization across all subbands.
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Perceptual versions (5-6) apply HVS-optimized quantisation weights per channel,
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while uniform versions (3-4) use consistent quantisation across all subbands.
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The encoder expects linear alpha.
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@@ -1083,20 +1087,11 @@ The encoder expects linear alpha.
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- Better frequency localization than DCT
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- Reduced blocking artifacts due to overlapping basis functions
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## Performance Comparison
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Expected improvements over TEV:
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- 20-30% better compression efficiency
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- Reduced blocking artifacts
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- Scalable quality/resolution decoding
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- Better performance on natural images vs artificial content
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- **Perceptual versions (5-6)**: Superior visual quality through HVS-optimized bit allocation
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- **Uniform versions (3-4)**: Backward compatibility with traditional quantization
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## Hardware Acceleration Functions
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TAV decoder requires new GraphicsJSR223Delegate functions:
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- tavDecode(): Main DWT decoding function
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- tavDWT2D(): 2D DWT/IDWT transforms
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- tavQuantize(): Multi-band quantization
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- tavQuantise(): Multi-band quantisation
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## Audio Support
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Reuses existing MP2 audio infrastructure from TEV/MOV formats for compatibility.
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