[nihav.git] / src / codecs / gremlinvideo.rs

use formats;
use super::*;
use io::byteio::*;

struct GremlinVideoDecoder {
    info:       Rc<NACodecInfo>,
    pal:        [u8; 768],
    frame:      Vec<u8>,
    scale_v:    bool,
    scale_h:    bool,
}

struct Bits8 {
    queue: u8,
    fill:  u8,
}

struct Bits32 {
    queue: u32,
    fill:  u8,
}

const PREAMBLE_SIZE: usize = 4096;

impl Bits8 {
    fn new() -> Self { Bits8 { queue: 0, fill: 0 } }
    fn read_2bits(&mut self, br: &mut ByteReader) -> ByteIOResult<u8> {
        if self.fill == 0 {
            self.queue  = br.read_byte()?;
            self.fill  += 8;
        }
        let res = self.queue >> 6;
        self.queue <<= 2;
        self.fill   -= 2;
        Ok(res)
    }
}

impl Bits32 {
    fn new() -> Self { Bits32 { queue: 0, fill: 0 } }
    fn fill(&mut self, br: &mut ByteReader) -> ByteIOResult<()> {
        self.queue = br.read_u32le()?;
        self.fill  = 32;
        Ok(())
    }
    fn read_bits(&mut self, br: &mut ByteReader, nbits: u8) -> ByteIOResult<u32> {
        let res = self.queue & ((1 << nbits) - 1);
        self.queue >>= nbits;
        self.fill   -= nbits;
        if self.fill <= 16 {
            self.queue |= (br.read_u16le()? as u32) << self.fill;
            self.fill  += 16;
        }
        Ok(res)
    }
}

impl GremlinVideoDecoder {
    fn new() -> Self {
        let dummy_info = Rc::new(DUMMY_CODEC_INFO);
        GremlinVideoDecoder {
            info: dummy_info, pal: [0; 768], frame: Vec::new(),
            scale_v: false, scale_h: false
        }
    }

    fn lz_copy(&mut self, idx: usize, offset: isize, len: usize) -> DecoderResult<()> {
        if idx + len > self.frame.len() { return Err(DecoderError::InvalidData); }
        if offset == -1 {
            let c = self.frame[idx - 1];
            for i in 0..len { self.frame[idx + i] = c; }
        } else if offset < 0 {
            let start = idx - (-offset as usize);
            for i in 0..len { self.frame[idx + i] = self.frame[start + i]; }
        } else {
            if idx + (offset as usize) + len > self.frame.len() { return Err(DecoderError::InvalidData); }
            let start = idx + (offset as usize);
            for i in 0..len { self.frame[idx + i] = self.frame[start + i]; }
        }
        Ok(())
    }

    fn rescale(&mut self, w: usize, h: usize, scale_v: bool, scale_h: bool) {
        if (self.scale_v == scale_v) && (self.scale_h == scale_h) { return; }

        if self.scale_h && self.scale_v {
            for j in 0..h {
                let y = h - j - 1;
                for i in 0..w {
                    let x = w - i - 1;
                    self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x/2 + (y/2) * (w/2)];
                }
            }
        } else if self.scale_h {
            for j in 0..h {
                let y = h - j - 1;
                for x in 0..w {
                    self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x + (y/2) * w];
                }
            }
        } else if self.scale_v {
            for j in 0..h {
                let y = h - j - 1;
                for i in 0..w {
                    let x = w - i - 1;
                    self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x/2 + y * (w/2)];
                }
            }
        }

        if scale_h && scale_v {
            for y in 0..h/2 {
                for x in 0..w/2 {
                    self.frame[PREAMBLE_SIZE + x + y * (w/2)] = self.frame[PREAMBLE_SIZE + x*2 + y*2 * w];
                }
            }
        } else if scale_h {
            for y in 0..h/2 {
                for x in 0..w {
                    self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x + y*2 * w];
                }
            }
        } else if scale_v {
            for y in 0..h {
                for x in 0..w/2 {
                    self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x*2 + y * w];
                }
            }
        }

        self.scale_v = scale_v;
        self.scale_h = scale_h;
    }

    fn output_frame(&mut self, bufinfo: &mut NABufferType, w: usize, h: usize) {
        let bufo = bufinfo.get_vbuf();
        let mut buf = bufo.unwrap();
        let paloff = buf.get_offset(1);
        let stride = buf.get_stride(0);
        let mut data = buf.get_data_mut();
        let dst = data.as_mut_slice();
        let mut sidx = PREAMBLE_SIZE;
        let mut didx = 0;

        for i in 0..768 { dst[paloff + i] = self.pal[i]; }
        if !self.scale_v && !self.scale_h {
            for _ in 0..h {
                for x in 0..w { dst[didx + x] = self.frame[sidx + x]; }
                sidx += w;
                didx += stride;
            }
        } else {
            for y in 0..h {
                if !self.scale_v {
                    for x in 0..w { dst[didx + x] = self.frame[sidx + x]; }
                } else {
                    for x in 0..w { dst[didx + x] = self.frame[sidx + x/2]; }
                }
                if !self.scale_h || ((y & 1) == 1) {
                    sidx += if !self.scale_v { w } else { w/2 };
                }
                didx += stride;
            }
        }
    }

    fn decode_method2(&mut self, br: &mut ByteReader) -> DecoderResult<()> {
        let mut bits = Bits8::new();

        let mut size = self.info.get_properties().get_video_info().unwrap().get_width() *
                        self.info.get_properties().get_video_info().unwrap().get_height();
        let mut idx = PREAMBLE_SIZE;
        if self.frame[8] != 0 {
            for c in 0..256 {
                for i in 0..16 { self.frame[c * 16 + i] = c as u8; }
            }
        }
        while size > 0 {
            let tag = bits.read_2bits(br)?;
            if tag == 0 {
                self.frame[idx] = br.read_byte()?;
                size -= 1;
                idx  += 1;
            } else if tag == 1 {
                let b = br.read_byte()?;
                let len = ((b & 0xF) as usize) + 3;
                let bot = (b >> 4) as isize;
                let off = ((br.read_byte()? as isize) << 4) + bot - 4096;
                validate!(len <= size);
                size -= len;
                self.lz_copy(idx, off, len)?;
                idx += len;
            } else if tag == 2 {
                let len = (br.read_byte()? as usize) + 2;
                validate!(len <= size);
                size -= len;
                idx += len;
            } else {
                break;
            }
        }
        Ok(())
    }

    fn decode_method5(&mut self, br: &mut ByteReader, skip: usize) -> DecoderResult<()> {
        let mut bits = Bits8::new();

        let mut size = self.info.get_properties().get_video_info().unwrap().get_width() *
                        self.info.get_properties().get_video_info().unwrap().get_height();
        let mut idx = PREAMBLE_SIZE;
        validate!(size >= skip);
        size -= skip;
        idx  += skip;
        while size > 0 {
            let tag = bits.read_2bits(br)?;
            if tag == 0 {
                self.frame[idx] = br.read_byte()?;
                size -= 1;
                idx  += 1;
            } else if tag == 1 {
                let b = br.read_byte()?;
                let len = ((b & 0xF) as usize) + 3;
                let bot = (b >> 4) as isize;
                let off = ((br.read_byte()? as isize) << 4) + bot - 4096;
                validate!(len <= size);
                size -= len;
                self.lz_copy(idx, off, len)?;
                idx += len;
            } else if tag == 2 {
                let b = br.read_byte()?;
                if b == 0 { break; }
                let len: usize = (if b != 0xFF { b as usize } else { br.read_u16le()? as usize }) + 1;
                validate!(len <= size);
                size -= len;
                idx += len;
            } else {
                let b = br.read_byte()?;
                let len = ((b & 0x3) as usize) + 2;
                let off = -((b >> 2) as isize) - 1;
                validate!(len <= size);
                size -= len;
                self.lz_copy(idx, off, len)?; 
                idx += len;
            }
        }
        Ok(())
    }

    fn decode_method68(&mut self, br: &mut ByteReader,
                       skip: usize, use8: bool) -> DecoderResult<()> {
        let mut bits = Bits32::new();

        let mut size = self.info.get_properties().get_video_info().unwrap().get_width() *
                        self.info.get_properties().get_video_info().unwrap().get_height();
        let mut idx = PREAMBLE_SIZE;
        validate!(size >= skip);
        size -= skip;
        idx  += skip;
        bits.fill(br)?;
        while size > 0 {
            let tag = bits.read_bits(br, 2)?;
            if tag == 0 { //draw
                let b = bits.read_bits(br, 1)?;
                if b == 0 {
                    self.frame[idx] = br.read_byte()?;
                    size -= 1;
                    idx  += 1;
                } else {
                    let mut len: usize = 2;
                    let mut lbits = 0;
                    loop {
                        lbits += 1;
                        let val = bits.read_bits(br, lbits)?;
                        len += val as usize;
                        if val != ((1 << lbits) - 1) { break; }
                        validate!(lbits < 16);
                    }
                    validate!(len <= size);
                    for i in 0..len { self.frame[idx + i] = br.read_byte()?; }
                    size -= len;
                    idx  += len;
                }
            } else if tag == 1 { //skip
                let b = bits.read_bits(br, 1)?;
                let len: usize;
                if b == 0 {
                    len = (bits.read_bits(br, 4)? as usize) + 2;
                } else {
                    let bb = br.read_byte()?;
                    if (bb & 0x80) == 0 {
                        len = (bb as usize) + 18;
                    } else {
                        let top = ((bb & 0x7F) as usize) << 8;
                        len = top + (br.read_byte()? as usize) + 146;
                    }
                }
                validate!(len <= size);
                size -= len;
                idx  += len;
            } else if tag == 2 {
                let subtag = bits.read_bits(br, 2)? as usize;
                if subtag != 3 {
                    let top = (bits.read_bits(br, 4)? as usize) << 8;
                    let offs = top + (br.read_byte()? as usize);
                    if (subtag != 0) || (offs <= 0xF80) {
                        let len = (subtag as usize) + 3;
                        self.lz_copy(idx, (offs as isize) - 4096, len)?;
                        idx += len;
                    } else {
                        if offs == 0xFFF { return Ok(()); }
                        let real_off = ((offs >> 4) & 0x7) + 1;
                        let len = ((offs & 0xF) + 2) * 2;
                        validate!(len <= size);
                        size -= len;
                        let c1 = self.frame[idx - real_off];
                        let c2 = self.frame[idx - real_off + 1];
                        for i in 0..len/2 {
                            self.frame[idx + i*2 + 0] = c1;
                            self.frame[idx + i*2 + 1] = c2;
                        }
                        idx += len;
                    }
                } else {
                    let b = br.read_byte()?;
                    let off = ((b & 0x7F) as usize) + 1;
                    let len = if (b & 0x80) == 0 { 2 } else { 3 };
                    validate!(len <= size);
                    size -= len;
                    self.lz_copy(idx, -(off as isize), len)?; 
                    idx += len;
                }
            } else {
                let len: usize;
                let off: isize;
                if use8 {
                    let b = br.read_byte()?;
                    if (b & 0xC0) == 0xC0 {
                        len = ((b & 0x3F) as usize) + 8;
                        let q = bits.read_bits(br, 4)? as isize;
                        off = (q << 8) + (br.read_byte()? as isize) + 1;
                    } else {
                        let ofs1: isize;
                        if (b & 0x80) == 0 {
                            len = ((b >> 4) as usize) + 6;
                            ofs1 = (b & 0xF) as isize;
                        } else {
                            len = ((b & 0x3F) as usize) + 14;
                            ofs1 = bits.read_bits(br, 4)? as isize;
                        }
                        off = (ofs1 << 8) + (br.read_byte()? as isize) - 4096;
                    }
                } else {
                    let b = br.read_byte()?;
                    if (b >> 4) == 0xF {
                        len = (br.read_byte()? as usize) + 21;
                    } else {
                        len = ((b >> 4) as usize) + 6;
                    }
                    let ofs1 = (b & 0xF) as isize;
                    off = (ofs1 << 8) + (br.read_byte()? as isize) - 4096;
                }
                validate!(len <= size);
                size -= len;
                self.lz_copy(idx, off, len)?; 
                idx += len;
            }
        }
        Ok(())
    }
}

impl NADecoder for GremlinVideoDecoder {
    fn init(&mut self, info: Rc<NACodecInfo>) -> DecoderResult<()> {
        if let NACodecTypeInfo::Video(vinfo) = info.get_properties() {
            let w = vinfo.get_width();
            let h = vinfo.get_height();
            if !vinfo.get_format().is_paletted() { return Err(DecoderError::NotImplemented); }
            let fmt = formats::PAL8_FORMAT;
            let myinfo = NACodecTypeInfo::Video(NAVideoInfo::new(w, h, false, fmt));
            self.info = Rc::new(NACodecInfo::new_ref(info.get_name(), myinfo, info.get_extradata()));

            self.frame.resize(PREAMBLE_SIZE + w * h, 0);
            for i in 0..2 {
                for j in 0..256 {
                    for k in 0..8 {
                        self.frame[i * 2048 + j * 8 + k] = j as u8;
                    }
                }
            }
            let edata = info.get_extradata().unwrap();
            validate!(edata.len() == 768);
            for c in 0..256 {
                for i in 0..3 {
                    let cc = edata[c * 3 + i];
                    self.pal[c * 3 + (2 - i)] = (cc << 2) | (cc >> 4);
                }
            }
            Ok(())
        } else {
            Err(DecoderError::InvalidData)
        }
    }
    fn decode(&mut self, pkt: &NAPacket) -> DecoderResult<NAFrameRef> {
        let src = pkt.get_buffer();
        let mut mr = MemoryReader::new_read(&src);
        let mut br = ByteReader::new(&mut mr);
        let flags = br.read_u32le()?;
        let w = self.info.get_properties().get_video_info().unwrap().get_width();
        let h = self.info.get_properties().get_video_info().unwrap().get_height();

        let cmethod = flags & 0xF;
        let is_intra = (flags & 0x40) != 0;
        let scale_v = (flags & 0x10) != 0;
        let scale_h = (flags & 0x20) != 0;

        self.rescale(w, h, scale_v, scale_h);

        if (cmethod == 0) || (cmethod == 1) {
            for c in 0..256 {
                for i in 0..3 {
                    let b = br.read_byte()?;
                    self.pal[c * 3 + (2 - i)] = (b << 2) | (b >> 4);
                }
            }
            if cmethod == 1 {
                for i in PREAMBLE_SIZE..self.frame.len() { self.frame[i] = 0x00; }
            }
            let mut frm = NAFrame::new_from_pkt(pkt, self.info.clone(), NABufferType::None);
            frm.set_keyframe(false);
            frm.set_frame_type(FrameType::Skip);
            return Ok(Rc::new(RefCell::new(frm)))
        } else if cmethod == 3 {
            let mut frm = NAFrame::new_from_pkt(pkt, self.info.clone(), NABufferType::None);
            frm.set_keyframe(false);
            frm.set_frame_type(FrameType::Skip);
            return Ok(Rc::new(RefCell::new(frm)))
        } else if cmethod == 2 {
            self.decode_method2(&mut br)?;
        } else if cmethod == 5 {
            self.decode_method5(&mut br, (flags >> 8) as usize)?;
        } else if cmethod == 6 {
            self.decode_method68(&mut br, (flags >> 8) as usize, false)?;
        } else if cmethod == 8 {
            self.decode_method68(&mut br, (flags >> 8) as usize, true)?;
        } else {
            return Err(DecoderError::NotImplemented);
        }

        let bufret = alloc_video_buffer(self.info.get_properties().get_video_info().unwrap(), 0);
        if let Err(_) = bufret { return Err(DecoderError::InvalidData); }
        let mut bufinfo = bufret.unwrap();

        self.output_frame(&mut bufinfo, w, h);

        let mut frm = NAFrame::new_from_pkt(pkt, self.info.clone(), bufinfo);
        frm.set_keyframe(is_intra);
        frm.set_frame_type(if is_intra { FrameType::I } else { FrameType::P });
        Ok(Rc::new(RefCell::new(frm)))
    }
}

pub fn get_decoder() -> Box<NADecoder> {
    Box::new(GremlinVideoDecoder::new())
}

#[cfg(test)]
mod test {
    use test::dec_video::test_file_decoding;
    #[test]
    fn test_gdv() {
         test_file_decoding("gdv", "assets/intro1.gdv", Some(10), true, false, None);
    }
}
Commit	Line	Data
	1	use formats;
	2	use super::*;
	3	use io::byteio::*;
	4
	5	struct GremlinVideoDecoder {
	6	info: Rc<NACodecInfo>,
	7	pal: [u8; 768],
	8	frame: Vec<u8>,
	9	scale_v: bool,
	10	scale_h: bool,
	11	}
	12
	13	struct Bits8 {
	14	queue: u8,
	15	fill: u8,
	16	}
	17
	18	struct Bits32 {
	19	queue: u32,
	20	fill: u8,
	21	}
	22
	23	const PREAMBLE_SIZE: usize = 4096;
	24
	25	impl Bits8 {
	26	fn new() -> Self { Bits8 { queue: 0, fill: 0 } }
	27	fn read_2bits(&mut self, br: &mut ByteReader) -> ByteIOResult<u8> {
	28	if self.fill == 0 {
	29	self.queue = br.read_byte()?;
	30	self.fill += 8;
	31	}
	32	let res = self.queue >> 6;
	33	self.queue <<= 2;
	34	self.fill -= 2;
	35	Ok(res)
	36	}
	37	}
	38
	39	impl Bits32 {
	40	fn new() -> Self { Bits32 { queue: 0, fill: 0 } }
	41	fn fill(&mut self, br: &mut ByteReader) -> ByteIOResult<()> {
	42	self.queue = br.read_u32le()?;
	43	self.fill = 32;
	44	Ok(())
	45	}
	46	fn read_bits(&mut self, br: &mut ByteReader, nbits: u8) -> ByteIOResult<u32> {
	47	let res = self.queue & ((1 << nbits) - 1);
	48	self.queue >>= nbits;
	49	self.fill -= nbits;
	50	if self.fill <= 16 {
	51	self.queue \|= (br.read_u16le()? as u32) << self.fill;
	52	self.fill += 16;
	53	}
	54	Ok(res)
	55	}
	56	}
	57
	58	impl GremlinVideoDecoder {
	59	fn new() -> Self {
	60	let dummy_info = Rc::new(DUMMY_CODEC_INFO);
	61	GremlinVideoDecoder {
	62	info: dummy_info, pal: [0; 768], frame: Vec::new(),
	63	scale_v: false, scale_h: false
	64	}
	65	}
	66
	67	fn lz_copy(&mut self, idx: usize, offset: isize, len: usize) -> DecoderResult<()> {
	68	if idx + len > self.frame.len() { return Err(DecoderError::InvalidData); }
	69	if offset == -1 {
	70	let c = self.frame[idx - 1];
	71	for i in 0..len { self.frame[idx + i] = c; }
	72	} else if offset < 0 {
	73	let start = idx - (-offset as usize);
	74	for i in 0..len { self.frame[idx + i] = self.frame[start + i]; }
	75	} else {
	76	if idx + (offset as usize) + len > self.frame.len() { return Err(DecoderError::InvalidData); }
	77	let start = idx + (offset as usize);
	78	for i in 0..len { self.frame[idx + i] = self.frame[start + i]; }
	79	}
	80	Ok(())
	81	}
	82
	83	fn rescale(&mut self, w: usize, h: usize, scale_v: bool, scale_h: bool) {
	84	if (self.scale_v == scale_v) && (self.scale_h == scale_h) { return; }
	85
	86	if self.scale_h && self.scale_v {
	87	for j in 0..h {
	88	let y = h - j - 1;
	89	for i in 0..w {
	90	let x = w - i - 1;
	91	self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x/2 + (y/2) * (w/2)];
	92	}
	93	}
	94	} else if self.scale_h {
	95	for j in 0..h {
	96	let y = h - j - 1;
	97	for x in 0..w {
	98	self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x + (y/2) * w];
	99	}
	100	}
	101	} else if self.scale_v {
	102	for j in 0..h {
	103	let y = h - j - 1;
	104	for i in 0..w {
	105	let x = w - i - 1;
	106	self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x/2 + y * (w/2)];
	107	}
	108	}
	109	}
	110
	111	if scale_h && scale_v {
	112	for y in 0..h/2 {
	113	for x in 0..w/2 {
	114	self.frame[PREAMBLE_SIZE + x + y * (w/2)] = self.frame[PREAMBLE_SIZE + x2 + y2 * w];
	115	}
	116	}
	117	} else if scale_h {
	118	for y in 0..h/2 {
	119	for x in 0..w {
	120	self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x + y2 w];
	121	}
	122	}
	123	} else if scale_v {
	124	for y in 0..h {
	125	for x in 0..w/2 {
	126	self.frame[PREAMBLE_SIZE + x + y * w] = self.frame[PREAMBLE_SIZE + x2 + y w];
	127	}
	128	}
	129	}
	130
	131	self.scale_v = scale_v;
	132	self.scale_h = scale_h;
	133	}
	134
	135	fn output_frame(&mut self, bufinfo: &mut NABufferType, w: usize, h: usize) {
	136	let bufo = bufinfo.get_vbuf();
	137	let mut buf = bufo.unwrap();
	138	let paloff = buf.get_offset(1);
	139	let stride = buf.get_stride(0);
	140	let mut data = buf.get_data_mut();
	141	let dst = data.as_mut_slice();
	142	let mut sidx = PREAMBLE_SIZE;
	143	let mut didx = 0;
	144
	145	for i in 0..768 { dst[paloff + i] = self.pal[i]; }
	146	if !self.scale_v && !self.scale_h {
	147	for _ in 0..h {
	148	for x in 0..w { dst[didx + x] = self.frame[sidx + x]; }
	149	sidx += w;
	150	didx += stride;
	151	}
	152	} else {
	153	for y in 0..h {
	154	if !self.scale_v {
	155	for x in 0..w { dst[didx + x] = self.frame[sidx + x]; }
	156	} else {
	157	for x in 0..w { dst[didx + x] = self.frame[sidx + x/2]; }
	158	}
	159	if !self.scale_h \|\| ((y & 1) == 1) {
	160	sidx += if !self.scale_v { w } else { w/2 };
	161	}
	162	didx += stride;
	163	}
	164	}
	165	}
	166
	167	fn decode_method2(&mut self, br: &mut ByteReader) -> DecoderResult<()> {
	168	let mut bits = Bits8::new();
	169
	170	let mut size = self.info.get_properties().get_video_info().unwrap().get_width() *
	171	self.info.get_properties().get_video_info().unwrap().get_height();
	172	let mut idx = PREAMBLE_SIZE;
	173	if self.frame[8] != 0 {
	174	for c in 0..256 {
	175	for i in 0..16 { self.frame[c * 16 + i] = c as u8; }
	176	}
	177	}
	178	while size > 0 {
	179	let tag = bits.read_2bits(br)?;
	180	if tag == 0 {
	181	self.frame[idx] = br.read_byte()?;
	182	size -= 1;
	183	idx += 1;
	184	} else if tag == 1 {
	185	let b = br.read_byte()?;
	186	let len = ((b & 0xF) as usize) + 3;
	187	let bot = (b >> 4) as isize;
	188	let off = ((br.read_byte()? as isize) << 4) + bot - 4096;
	189	validate!(len <= size);
	190	size -= len;
	191	self.lz_copy(idx, off, len)?;
	192	idx += len;
	193	} else if tag == 2 {
	194	let len = (br.read_byte()? as usize) + 2;
	195	validate!(len <= size);
	196	size -= len;
	197	idx += len;
	198	} else {
	199	break;
	200	}
	201	}
	202	Ok(())
	203	}
	204
	205	fn decode_method5(&mut self, br: &mut ByteReader, skip: usize) -> DecoderResult<()> {
	206	let mut bits = Bits8::new();
	207
	208	let mut size = self.info.get_properties().get_video_info().unwrap().get_width() *
	209	self.info.get_properties().get_video_info().unwrap().get_height();
	210	let mut idx = PREAMBLE_SIZE;
	211	validate!(size >= skip);
	212	size -= skip;
	213	idx += skip;
	214	while size > 0 {
	215	let tag = bits.read_2bits(br)?;
	216	if tag == 0 {
	217	self.frame[idx] = br.read_byte()?;
	218	size -= 1;
	219	idx += 1;
	220	} else if tag == 1 {
	221	let b = br.read_byte()?;
	222	let len = ((b & 0xF) as usize) + 3;
	223	let bot = (b >> 4) as isize;
	224	let off = ((br.read_byte()? as isize) << 4) + bot - 4096;
	225	validate!(len <= size);
	226	size -= len;
	227	self.lz_copy(idx, off, len)?;
	228	idx += len;
	229	} else if tag == 2 {
	230	let b = br.read_byte()?;
	231	if b == 0 { break; }
	232	let len: usize = (if b != 0xFF { b as usize } else { br.read_u16le()? as usize }) + 1;
	233	validate!(len <= size);
	234	size -= len;
	235	idx += len;
	236	} else {
	237	let b = br.read_byte()?;
	238	let len = ((b & 0x3) as usize) + 2;
	239	let off = -((b >> 2) as isize) - 1;
	240	validate!(len <= size);
	241	size -= len;
	242	self.lz_copy(idx, off, len)?;
	243	idx += len;
	244	}
	245	}
	246	Ok(())
	247	}
	248
	249	fn decode_method68(&mut self, br: &mut ByteReader,
	250	skip: usize, use8: bool) -> DecoderResult<()> {
	251	let mut bits = Bits32::new();
	252
	253	let mut size = self.info.get_properties().get_video_info().unwrap().get_width() *
	254	self.info.get_properties().get_video_info().unwrap().get_height();
	255	let mut idx = PREAMBLE_SIZE;
	256	validate!(size >= skip);
	257	size -= skip;
	258	idx += skip;
	259	bits.fill(br)?;
	260	while size > 0 {
	261	let tag = bits.read_bits(br, 2)?;
	262	if tag == 0 { //draw
	263	let b = bits.read_bits(br, 1)?;
	264	if b == 0 {
	265	self.frame[idx] = br.read_byte()?;
	266	size -= 1;
	267	idx += 1;
	268	} else {
	269	let mut len: usize = 2;
	270	let mut lbits = 0;
	271	loop {
	272	lbits += 1;
	273	let val = bits.read_bits(br, lbits)?;
	274	len += val as usize;
	275	if val != ((1 << lbits) - 1) { break; }
	276	validate!(lbits < 16);
	277	}
	278	validate!(len <= size);
	279	for i in 0..len { self.frame[idx + i] = br.read_byte()?; }
	280	size -= len;
	281	idx += len;
	282	}
	283	} else if tag == 1 { //skip
	284	let b = bits.read_bits(br, 1)?;
	285	let len: usize;
	286	if b == 0 {
	287	len = (bits.read_bits(br, 4)? as usize) + 2;
	288	} else {
	289	let bb = br.read_byte()?;
	290	if (bb & 0x80) == 0 {
	291	len = (bb as usize) + 18;
	292	} else {
	293	let top = ((bb & 0x7F) as usize) << 8;
	294	len = top + (br.read_byte()? as usize) + 146;
	295	}
	296	}
	297	validate!(len <= size);
	298	size -= len;
	299	idx += len;
	300	} else if tag == 2 {
	301	let subtag = bits.read_bits(br, 2)? as usize;
	302	if subtag != 3 {
	303	let top = (bits.read_bits(br, 4)? as usize) << 8;
	304	let offs = top + (br.read_byte()? as usize);
	305	if (subtag != 0) \|\| (offs <= 0xF80) {
	306	let len = (subtag as usize) + 3;
	307	self.lz_copy(idx, (offs as isize) - 4096, len)?;
	308	idx += len;
	309	} else {
	310	if offs == 0xFFF { return Ok(()); }
	311	let real_off = ((offs >> 4) & 0x7) + 1;
	312	let len = ((offs & 0xF) + 2) * 2;
	313	validate!(len <= size);
	314	size -= len;
	315	let c1 = self.frame[idx - real_off];
	316	let c2 = self.frame[idx - real_off + 1];
	317	for i in 0..len/2 {
	318	self.frame[idx + i*2 + 0] = c1;
	319	self.frame[idx + i*2 + 1] = c2;
	320	}
	321	idx += len;
	322	}
	323	} else {
	324	let b = br.read_byte()?;
	325	let off = ((b & 0x7F) as usize) + 1;
	326	let len = if (b & 0x80) == 0 { 2 } else { 3 };
	327	validate!(len <= size);
	328	size -= len;
	329	self.lz_copy(idx, -(off as isize), len)?;
	330	idx += len;
	331	}
	332	} else {
	333	let len: usize;
	334	let off: isize;
	335	if use8 {
	336	let b = br.read_byte()?;
	337	if (b & 0xC0) == 0xC0 {
	338	len = ((b & 0x3F) as usize) + 8;
	339	let q = bits.read_bits(br, 4)? as isize;
	340	off = (q << 8) + (br.read_byte()? as isize) + 1;
	341	} else {
	342	let ofs1: isize;
	343	if (b & 0x80) == 0 {
	344	len = ((b >> 4) as usize) + 6;
	345	ofs1 = (b & 0xF) as isize;
	346	} else {
	347	len = ((b & 0x3F) as usize) + 14;
	348	ofs1 = bits.read_bits(br, 4)? as isize;
	349	}
	350	off = (ofs1 << 8) + (br.read_byte()? as isize) - 4096;
	351	}
	352	} else {
	353	let b = br.read_byte()?;
	354	if (b >> 4) == 0xF {
	355	len = (br.read_byte()? as usize) + 21;
	356	} else {
	357	len = ((b >> 4) as usize) + 6;
	358	}
	359	let ofs1 = (b & 0xF) as isize;
	360	off = (ofs1 << 8) + (br.read_byte()? as isize) - 4096;
	361	}
	362	validate!(len <= size);
	363	size -= len;
	364	self.lz_copy(idx, off, len)?;
	365	idx += len;
	366	}
	367	}
	368	Ok(())
	369	}
	370	}
	371
	372	impl NADecoder for GremlinVideoDecoder {
	373	fn init(&mut self, info: Rc<NACodecInfo>) -> DecoderResult<()> {
	374	if let NACodecTypeInfo::Video(vinfo) = info.get_properties() {
	375	let w = vinfo.get_width();
	376	let h = vinfo.get_height();
	377	if !vinfo.get_format().is_paletted() { return Err(DecoderError::NotImplemented); }
	378	let fmt = formats::PAL8_FORMAT;
	379	let myinfo = NACodecTypeInfo::Video(NAVideoInfo::new(w, h, false, fmt));
	380	self.info = Rc::new(NACodecInfo::new_ref(info.get_name(), myinfo, info.get_extradata()));
	381
	382	self.frame.resize(PREAMBLE_SIZE + w * h, 0);
	383	for i in 0..2 {
	384	for j in 0..256 {
	385	for k in 0..8 {
	386	self.frame[i * 2048 + j * 8 + k] = j as u8;
	387	}
	388	}
	389	}
	390	let edata = info.get_extradata().unwrap();
	391	validate!(edata.len() == 768);
	392	for c in 0..256 {
	393	for i in 0..3 {
	394	let cc = edata[c * 3 + i];
	395	self.pal[c * 3 + (2 - i)] = (cc << 2) \| (cc >> 4);
	396	}
	397	}
	398	Ok(())
	399	} else {
	400	Err(DecoderError::InvalidData)
	401	}
	402	}
	403	fn decode(&mut self, pkt: &NAPacket) -> DecoderResult<NAFrameRef> {
	404	let src = pkt.get_buffer();
	405	let mut mr = MemoryReader::new_read(&src);
	406	let mut br = ByteReader::new(&mut mr);
	407	let flags = br.read_u32le()?;
	408	let w = self.info.get_properties().get_video_info().unwrap().get_width();
	409	let h = self.info.get_properties().get_video_info().unwrap().get_height();
	410
	411	let cmethod = flags & 0xF;
	412	let is_intra = (flags & 0x40) != 0;
	413	let scale_v = (flags & 0x10) != 0;
	414	let scale_h = (flags & 0x20) != 0;
	415
	416	self.rescale(w, h, scale_v, scale_h);
	417
	418	if (cmethod == 0) \|\| (cmethod == 1) {
	419	for c in 0..256 {
	420	for i in 0..3 {
	421	let b = br.read_byte()?;
	422	self.pal[c * 3 + (2 - i)] = (b << 2) \| (b >> 4);
	423	}
	424	}
	425	if cmethod == 1 {
	426	for i in PREAMBLE_SIZE..self.frame.len() { self.frame[i] = 0x00; }
	427	}
	428	let mut frm = NAFrame::new_from_pkt(pkt, self.info.clone(), NABufferType::None);
	429	frm.set_keyframe(false);
	430	frm.set_frame_type(FrameType::Skip);
	431	return Ok(Rc::new(RefCell::new(frm)))
	432	} else if cmethod == 3 {
	433	let mut frm = NAFrame::new_from_pkt(pkt, self.info.clone(), NABufferType::None);
	434	frm.set_keyframe(false);
	435	frm.set_frame_type(FrameType::Skip);
	436	return Ok(Rc::new(RefCell::new(frm)))
	437	} else if cmethod == 2 {
	438	self.decode_method2(&mut br)?;
	439	} else if cmethod == 5 {
	440	self.decode_method5(&mut br, (flags >> 8) as usize)?;
	441	} else if cmethod == 6 {
	442	self.decode_method68(&mut br, (flags >> 8) as usize, false)?;
	443	} else if cmethod == 8 {
	444	self.decode_method68(&mut br, (flags >> 8) as usize, true)?;
	445	} else {
	446	return Err(DecoderError::NotImplemented);
	447	}
	448
	449	let bufret = alloc_video_buffer(self.info.get_properties().get_video_info().unwrap(), 0);
	450	if let Err(_) = bufret { return Err(DecoderError::InvalidData); }
	451	let mut bufinfo = bufret.unwrap();
	452
	453	self.output_frame(&mut bufinfo, w, h);
	454
	455	let mut frm = NAFrame::new_from_pkt(pkt, self.info.clone(), bufinfo);
	456	frm.set_keyframe(is_intra);
	457	frm.set_frame_type(if is_intra { FrameType::I } else { FrameType::P });
	458	Ok(Rc::new(RefCell::new(frm)))
	459	}
	460	}
	461
	462	pub fn get_decoder() -> Box<NADecoder> {
	463	Box::new(GremlinVideoDecoder::new())
	464	}
	465
	466	#[cfg(test)]
	467	mod test {
	468	use test::dec_video::test_file_decoding;
	469	#[test]
	470	fn test_gdv() {
	471	test_file_decoding("gdv", "assets/intro1.gdv", Some(10), true, false, None);
	472	}
	473	}