VP7 decoder

[nihav.git] / nihav-duck / src / codecs / vpcommon.rs

diff --git a/nihav-duck/src/codecs/vpcommon.rs b/nihav-duck/src/codecs/vpcommon.rs
index 0392a383b5248a4647e3b734b43534668e07c4f2..562a9a2601dcbaf0c4d09983e4312b39390baf74 100644 (file)
--- a/nihav-duck/src/codecs/vpcommon.rs
+++ b/nihav-duck/src/codecs/vpcommon.rs
@@ -70,6 +70,16 @@ impl VPShuffler {
     }
 }
 
+pub const VP56_COEF_BASE: [i16; 6] = [ 5, 7, 11, 19, 35, 67 ];
+pub const VP56_COEF_ADD_PROBS: [[u8; 12]; 6] = [
+    [ 159, 128,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0 ],
+    [ 165, 145, 128,   0,   0,   0,   0,   0,   0,   0,   0,   0 ],
+    [ 173, 148, 140, 128,   0,   0,   0,   0,   0,   0,   0,   0 ],
+    [ 176, 155, 140, 135, 128,   0,   0,   0,   0,   0,   0,   0 ],
+    [ 180, 157, 141, 134, 130, 128,   0,   0,   0,   0,   0,   0 ],
+    [ 254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129, 128 ],
+];
+
 #[allow(dead_code)]
 pub struct BoolCoder<'a> {
     pub src:    &'a [u8],
@@ -110,6 +120,20 @@ impl<'a> BoolCoder<'a> {
         }
         val
     }
+    pub fn read_byte(&mut self) -> u8 {
+        let mut val = 0u8;
+        for _ in 0..8 {
+            val = (val << 1) | (self.read_prob(128) as u8);
+        }
+        val
+    }
+    pub fn read_sbits(&mut self, bits: u8) -> i32 {
+        let mut val = if self.read_prob(128) { -1i32 } else { 0i32 };
+        for _ in 1..bits {
+            val = (val << 1) | (self.read_prob(128) as i32);
+        }
+        val
+    }
     pub fn read_probability(&mut self) -> u8 {
         let val = self.read_bits(7) as u8;
         if val == 0 {