yop.c File Reference

#include <string.h>
#include "libavutil/imgutils.h"
#include "libavutil/internal.h"
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "internal.h"

Go to the source code of this file.

Data Structures
struct	YopDecContext

Functions
static av_cold int	yop_decode_close (AVCodecContext *avctx)
static av_cold int	yop_decode_init (AVCodecContext *avctx)
static int	yop_paint_block (YopDecContext *s, int linesize, int tag)
	Paint a macroblock using the pattern in paint_lut. More...
static int	yop_copy_previous_block (YopDecContext *s, int linesize, int copy_tag)
	Copy a previously painted macroblock to the current_block. More...
static uint8_t	yop_get_next_nibble (YopDecContext *s)
	Return the next nibble in sequence, consuming a new byte on the input only if necessary. More...
static int	yop_decode_frame (AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)

Variables
static const uint8_t	paint_lut [15][4]
	Lookup table for painting macroblocks. More...
static const int8_t	motion_vector [16][2]
	Lookup table for copying macroblocks. More...
AVCodec	ff_yop_decoder

Function Documentation

yop_decode_close()

static av_cold int yop_decode_close ( AVCodecContext *  avctx )

static

Definition at line 84 of file yop.c.

yop_decode_init()

static av_cold int yop_decode_init ( AVCodecContext *  avctx )

static

Definition at line 93 of file yop.c.

yop_paint_block()

static int yop_paint_block ( YopDecContext *  s, int  linesize, int  tag  )

static

Paint a macroblock using the pattern in paint_lut.

Parameters

s	codec context
tag	the tag that was in the nibble

Definition at line 134 of file yop.c.

Referenced by yop_decode_frame().

yop_copy_previous_block()

static int yop_copy_previous_block ( YopDecContext *  s, int  linesize, int  copy_tag  )

static

Copy a previously painted macroblock to the current_block.

Parameters

copy_tag

the tag that was in the nibble

Definition at line 155 of file yop.c.

Referenced by yop_decode_frame().

yop_get_next_nibble()

static uint8_t yop_get_next_nibble ( YopDecContext *  s )

static

Return the next nibble in sequence, consuming a new byte on the input only if necessary.

Definition at line 179 of file yop.c.

Referenced by yop_decode_frame().

yop_decode_frame()

static int yop_decode_frame ( AVCodecContext *  avctx, void *  data, int *  got_frame, AVPacket *  avpkt  )

static

Definition at line 193 of file yop.c.

Variable Documentation

paint_lut

const uint8_t paint_lut[15][4]

static

Initial value:

=
    {{1, 2, 3, 4}, {1, 2, 0, 3},
     {1, 2, 1, 3}, {1, 2, 2, 3},
     {1, 0, 2, 3}, {1, 0, 0, 2},
     {1, 0, 1, 2}, {1, 1, 2, 3},
     {0, 1, 2, 3}, {0, 1, 0, 2},
     {1, 1, 0, 2}, {0, 1, 1, 2},
     {0, 0, 1, 2}, {0, 0, 0, 1},
     {1, 1, 1, 2},
    }

Lookup table for painting macroblocks.

Bytes 0-2 of each entry contain the macroblock positions to be painted (taken as (0, B0, B1, B2)). Byte 3 contains the number of bytes consumed on the input, equal to max(bytes 0-2) + 1.

Definition at line 58 of file yop.c.

Referenced by yop_paint_block().

motion_vector

const int8_t motion_vector[16][2]

static

Initial value:

=
    {{-4, -4}, {-2, -4},
     { 0, -4}, { 2, -4},
     {-4, -2}, {-4,  0},
     {-3, -3}, {-1, -3},
     { 1, -3}, { 3, -3},
     {-3, -1}, {-2, -2},
     { 0, -2}, { 2, -2},
     { 4, -2}, {-2,  0},
    }

Lookup table for copying macroblocks.

Each entry contains the respective x and y pixel offset for the copy source.

Definition at line 73 of file yop.c.

Referenced by yop_copy_previous_block().

ff_yop_decoder

AVCodec ff_yop_decoder

Initial value:

= {
    .name           = "yop",
    .long_name      = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_YOP,
    .priv_data_size = sizeof(YopDecContext),
    .init           = yop_decode_init,
    .close          = yop_decode_close,
    .decode         = yop_decode_frame,
}

Definition at line 268 of file yop.c.