Indeo 3 encoder

[nihav.git] / nihav-indeo / src / codecs / indeo3enc / ratectl.rs

diff --git a/nihav-indeo/src/codecs/indeo3enc/ratectl.rs b/nihav-indeo/src/codecs/indeo3enc/ratectl.rs
new file mode 100644 (file)
index 0000000..4bb74c0
--- /dev/null
+++ b/nihav-indeo/src/codecs/indeo3enc/ratectl.rs
@@ -0,0 +1,77 @@
+#[derive(Default)]
+pub struct RateControl {
+    bitrate:    u32,
+    br_pool:    u32,
+    f_pos:      u32,
+    fracs:      u32,
+    key_int:    u32,
+    tb_num:     u32,
+    tb_den:     u32,
+    quality:    Option<u8>,
+}
+
+impl RateControl {
+    pub fn new() -> Self { Self{ key_int: 10, ..Default::default() } }
+    pub fn set_quality(&mut self, quality: u8) {
+        if quality > 0 {
+            self.quality = Some((quality - 1).min(15));
+        } else {
+            self.quality = None;
+        }
+    }
+    pub fn set_bitrate(&mut self, br: u32, tb_num: u32, tb_den: u32) {
+        if tb_num > 0 && tb_den > 0 {
+            self.bitrate = br / 8;
+            self.tb_num  = tb_num;
+            self.tb_den  = tb_den;
+        } else {
+            self.bitrate = 0;
+            self.tb_num  = 0;
+            self.tb_den  = 0;
+        }
+        self.quality = Some(0);
+        self.reset();
+    }
+    pub fn set_key_int(&mut self, key_int: u32) {
+        self.key_int = key_int;
+        self.reset();
+    }
+    pub fn reset(&mut self) {
+        self.br_pool = self.bitrate;
+        self.f_pos   = 0;
+        self.fracs   = self.tb_den;
+    }
+    pub fn get_key_int(&self) -> u32 { self.key_int }
+    pub fn get_quant(&self, frameno: u32) -> (bool, Option<u8>) {
+        let is_intra = self.key_int == 0 || (frameno % self.key_int) == 0;
+        (is_intra, self.quality)
+    }
+    pub fn advance(&mut self, size: u32) {
+        if self.bitrate != 0 {
+            let expected = self.get_expected_size();
+            let cur_quant = self.quality.unwrap_or(0);
+            if (size > expected + expected / 10) && (cur_quant < 7) {
+                self.quality = Some(cur_quant + 1);
+            } else if (size < expected - expected / 10) && (cur_quant > 0) {
+                self.quality = Some(cur_quant - 1);
+            }
+
+            self.f_pos += self.tb_num;
+            while self.f_pos >= self.tb_den {
+                self.f_pos   -= self.tb_den;
+                self.br_pool += self.bitrate;
+                self.fracs   += self.tb_den;
+            }
+            self.fracs -= self.tb_num;
+
+            self.br_pool = self.br_pool.saturating_sub(size).min(self.bitrate * 3);
+        }
+    }
+    pub fn get_expected_size(&self) -> u32 {
+        if self.bitrate != 0 {
+            self.br_pool * self.tb_num / self.fracs
+        } else {
+            0
+        }
+    }
+}