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TAV: revised psychovisual model

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minjaesong
2025-10-01 12:21:04 +09:00
parent 3e40b048a7
commit b9f38dfa08
2 changed files with 17 additions and 12 deletions
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13
tsvm_core/src/net/torvald/tsvm/GraphicsJSR223Delegate.kt
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@@ -4148,12 +4148,15 @@ class GraphicsJSR223Delegate(private val vm: VM) {
private fun perceptual_model3_LH(quality: Int, level: Float): Float { private fun perceptual_model3_LH(quality: Int, level: Float): Float {
val H4 = 1.2f val H4 = 1.2f
val Lx = H4 - ((quality + 1f) / 15f) * (level - 4f) val Q = 2f // using fixed value for fixed curve; quantiser will scale it up anyway
val Ld = (quality + 1f) / -15f val Q12 = Q * 12f
val C = H4 - 4f * Ld - ((-16f * (quality - 5f)) / (15f)) val x = level
val Gx = (Ld * level) - (((quality - 5f) * (level - 8f) * level) / (15f)) + C
return if (level >= 4) Lx else Gx val Lx = H4 - ((Q + 1f) / 15f) * (x - 4f)
val C3 = -1f / 45f * (Q12 + 92)
val G3x = (-x / 180f) * (Q12 + 5 * x * x - 60 * x + 252) - C3 + H4
return if (level >= 4) Lx else G3x
} }
private fun perceptual_model3_HL(quality: Int, LH: Float): Float { private fun perceptual_model3_HL(quality: Int, LH: Float): Float {

16
video_encoder/encoder_tav.c
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@@ -1386,15 +1386,17 @@ static void quantise_dwt_coefficients(float *coeffs, int16_t *quantised, int siz
} }
// https://www.desmos.com/calculator/mjlpwqm8ge // https://www.desmos.com/calculator/mjlpwqm8ge
// where Q=quality, x=level
static float perceptual_model3_LH(int quality, float level) { static float perceptual_model3_LH(int quality, float level) {
float H4 = 1.2f; float H4 = 1.2f;
float Lx = H4 - ((quality + 1.f) / 15.f) * (level - 4.f); float Q = 2.f; // using fixed value for fixed curve; quantiser will scale it up anyway
float Ld = (quality + 1.f) / -15.f; float Q12 = Q * 12.f;
float C = H4 - 4.f * Ld - ((-16.f*(quality - 5.f))/(15.f)); float x = level;
float Gx = (Ld * level) - (((quality - 5.f)*(level - 8.f)*level)/(15.f)) + C;
return (level >= 4) ? Lx : Gx; float Lx = H4 - ((Q + 1.f) / 15.f) * (x - 4.f);
float C3 = -1.f / 45.f * (Q12 + 92);
float G3x = (-x / 180.f) * (Q12 + 5*x*x - 60*x + 252) - C3 + H4;
return (level >= 4) ? Lx : G3x;
} }
static float perceptual_model3_HL(int quality, float LH) { static float perceptual_model3_HL(int quality, float LH) {
@@ -1406,7 +1408,7 @@ static float lerp(float x, float y, float a) {
} }
static float perceptual_model3_HH(float LH, float HL, float level) { static float perceptual_model3_HH(float LH, float HL, float level) {
float Kx = (sqrtf(level) - 1.f) * 0.5f + 0.5f; float Kx = fmaf((sqrtf(level) - 1.f), 0.5f, 0.5f);
return lerp(LH, HL, Kx); return lerp(LH, HL, Kx);
} }