h263+rv20: use modified dquant and chroma quant

4 files changed, 35 insertions, 12 deletions

diff --git a/src/codecs/h263/data.rs b/src/codecs/h263/data.rs
index 38fa6ca..b5d3cb1 100644
--- a/src/codecs/h263/data.rs
+++ b/src/codecs/h263/data.rs
@@ -96,6 +96,21 @@ pub const H263_CBPC_B: &[(u8, u8)] = &[
 
 pub const H263_DQUANT_TAB: &[i8] = &[-1, -2, 1, 2];
 
+pub const H263_MODIFIED_QUANT: [[u8; 32]; 2] = [
+  [
+     0,  3,  1,  2,  3,  4,  5,  6,  7,  8,  9,  9, 10, 11, 12, 13,
+    14, 15, 16, 17, 18, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28
+  ], [
+     0,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 13, 14, 15, 16, 17,
+    18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30, 31, 31, 31, 26
+  ]
+];
+
+pub const H263_CHROMA_QUANT: [u8; 32] = [
+     0,  1,  2,  3,  4,  5,  6,  6,  7,  8,  9,  9, 10, 10, 11, 11,
+    12, 12, 12, 13, 13, 13, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15
+];
+
 pub struct H263ShortCodeReader { tab: &'static [(u8, u8)] }
 
 impl H263ShortCodeReader {
diff --git a/src/codecs/h263/decoder.rs b/src/codecs/h263/decoder.rs
index f871bbd..08b4751 100644
--- a/src/codecs/h263/decoder.rs
+++ b/src/codecs/h263/decoder.rs
@@ -243,6 +243,7 @@ impl H263BaseDecoder {
             self.pred_coeffs.truncate(0);
             self.pred_coeffs.resize(self.mb_w * self.mb_h, ZERO_PRED_COEFFS);
         }
+        sstate.quant = slice.quant;
         for mb_y in 0..self.mb_h {
             for mb_x in 0..self.mb_w {
                 for i in 0..6 { for j in 0..64 { blk[i][j] = 0; } }
@@ -256,6 +257,7 @@ impl H263BaseDecoder {
                         }
                         cbpi.reset(self.mb_w);
                         sstate.reset_slice(mb_x, mb_y);
+                        sstate.quant = slice.quant;
                     }
                 }
 
@@ -263,6 +265,7 @@ impl H263BaseDecoder {
                 let cbp = binfo.get_cbp();
                 cbpi.set_cbp(mb_x, cbp);
                 cbpi.set_q(mb_x, binfo.get_q());
+                sstate.quant = binfo.get_q();
                 if binfo.is_intra() {
                     if save_b_data {
                         self.mv_data.push(BlockMVInfo::Intra);
diff --git a/src/codecs/h263/mod.rs b/src/codecs/h263/mod.rs
index 50eed7d..aa274e7 100644
--- a/src/codecs/h263/mod.rs
+++ b/src/codecs/h263/mod.rs
@@ -137,6 +137,7 @@ pub struct SliceState {
     pub first_mb:   bool,
     pub slice_mb_x: usize,
     pub slice_mb_y: usize,
+    pub quant:      u8,
 }
 
 const SLICE_NO_END: usize = 99999999;
@@ -160,7 +161,7 @@ impl SliceState {
     pub fn new(is_iframe: bool) -> Self {
         SliceState {
             is_iframe: is_iframe, mb_x: 0, mb_y: 0, first_line: true, first_mb: true,
-            slice_mb_x: 0, slice_mb_y: 0
+            slice_mb_x: 0, slice_mb_y: 0, quant: 0
         }
     }
     pub fn next_mb(&mut self) {
diff --git a/src/codecs/h263/rv20.rs b/src/codecs/h263/rv20.rs
index 9e62875..3b9fa1b 100644
--- a/src/codecs/h263/rv20.rs
+++ b/src/codecs/h263/rv20.rs
@@ -129,7 +129,7 @@ impl<'a> RealVideo20BR<'a> {
 
         let rl_cb = if sstate.is_iframe { &self.tables.aic_rl_cb } else { &self.tables.rl_cb };
         let q_add = if quant == 0 || sstate.is_iframe { 0i16 } else { ((quant - 1) | 1) as i16 };
-        let q = (quant * 2) as i16;
+        let q = if plane_no == 0 { (quant * 2) as i16 } else { H263_CHROMA_QUANT[quant as usize] as i16 };
         while idx < 64 {
             let code = br.read_cb(rl_cb)?;
             let run;
@@ -181,6 +181,14 @@ fn decode_mv(br: &mut BitReader, mv_cb: &Codebook<u8>) -> DecoderResult<MV> {
     Ok(MV::new(xval, yval))
 }
 
+fn read_dquant(br: &mut BitReader, q: u8) -> DecoderResult<u8> {
+    if br.read_bool()? {
+        Ok(H263_MODIFIED_QUANT[br.read(1)? as usize][q as usize])
+    } else {
+        Ok(br.read(5)? as u8)
+    }
+}
+
 impl<'a> BlockDecoder for RealVideo20BR<'a> {
 
 #[allow(unused_variables)]
@@ -222,9 +230,9 @@ impl<'a> BlockDecoder for RealVideo20BR<'a> {
         Ok(ret)
     }
 
-    fn decode_block_header(&mut self, info: &PicInfo, slice: &SliceInfo, _sstate: &SliceState) -> DecoderResult<BlockInfo> {
+    fn decode_block_header(&mut self, info: &PicInfo, _slice: &SliceInfo, sstate: &SliceState) -> DecoderResult<BlockInfo> {
         let br = &mut self.br;
-        let mut q = slice.get_quant();
+        let mut q = sstate.quant;
         match info.get_mode() {
             Type::I => {
                     let mut cbpc = br.read_cb(&self.tables.intra_mcbpc_cb)?;
@@ -243,8 +251,7 @@ impl<'a> BlockDecoder for RealVideo20BR<'a> {
                     let cbp = (cbpy << 2) | (cbpc & 3);
                     let dquant = (cbpc & 4) != 0;
                     if dquant {
-                        let idx = br.read(2)? as usize;
-                        q = ((q as i16) + (H263_DQUANT_TAB[idx] as i16)) as u8;
+                        q = read_dquant(br, q)?;
                     }
                     let mut binfo = BlockInfo::new(Type::I, cbp, q);
                     binfo.set_acpred(acpred);
@@ -263,8 +270,7 @@ impl<'a> BlockDecoder for RealVideo20BR<'a> {
                         let cbpy = br.read_cb(&self.tables.cbpy_cb)?;
                         let cbp = (cbpy << 2) | (cbpc & 3);
                         if dquant {
-                            let idx = br.read(2)? as usize;
-                            q = ((q as i16) + (H263_DQUANT_TAB[idx] as i16)) as u8;
+                            q = read_dquant(br, q)?;
                         }
                         let binfo = BlockInfo::new(Type::I, cbp, q);
                         return Ok(binfo);
@@ -276,8 +282,7 @@ impl<'a> BlockDecoder for RealVideo20BR<'a> {
 //                    }
                     let cbp = (cbpy << 2) | (cbpc & 3);
                     if dquant {
-                        let idx = br.read(2)? as usize;
-                        q = ((q as i16) + (H263_DQUANT_TAB[idx] as i16)) as u8;
+                        q = read_dquant(br, q)?;
                     }
                     let mut binfo = BlockInfo::new(Type::P, cbp, q);
                     if !is_4x4 {
@@ -312,8 +317,7 @@ impl<'a> BlockDecoder for RealVideo20BR<'a> {
                         } else { 0 };
 
                     if dquant {
-                        let idx = br.read(2)? as usize;
-                        q = ((q as i16) + (H263_DQUANT_TAB[idx] as i16)) as u8;
+                        q = read_dquant(br, q)?;
                     }
 
                     if is_intra {