#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "bytestream.h"
#include "get_bits.h"
#include "libavutil/lzo.h"
Go to the source code of this file.
Data Structures | |
| struct | XanContext |
Defines | |
| #define | BITSTREAM_READER_LE |
| #define | RUNTIME_GAMMA 0 |
| #define | VGA__TAG MKTAG('V', 'G', 'A', ' ') |
| #define | PALT_TAG MKTAG('P', 'A', 'L', 'T') |
| #define | SHOT_TAG MKTAG('S', 'H', 'O', 'T') |
| #define | PALETTE_COUNT 256 |
| #define | PALETTE_SIZE (PALETTE_COUNT * 3) |
| #define | PALETTES_MAX 256 |
Functions | |
| static av_cold int | xan_decode_init (AVCodecContext *avctx) |
| static int | xan_huffman_decode (unsigned char *dest, int dest_len, const unsigned char *src, int src_len) |
| static void | xan_unpack (unsigned char *dest, int dest_len, const unsigned char *src, int src_len) |
| unpack simple compression | |
| static void | xan_wc3_output_pixel_run (XanContext *s, const unsigned char *pixel_buffer, int x, int y, int pixel_count) |
| static void | xan_wc3_copy_pixel_run (XanContext *s, int x, int y, int pixel_count, int motion_x, int motion_y) |
| static int | xan_wc3_decode_frame (XanContext *s) |
| static int | xan_decode_frame (AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) |
| static av_cold int | xan_decode_end (AVCodecContext *avctx) |
Variables | |
| static const uint8_t | gamma_lookup [256] |
| This is a gamma correction that xan3 applies to all palette entries. | |
| AVCodec | ff_xan_wc3_decoder |
The xan_wc3 decoder outputs PAL8 data.
Definition in file xan.c.
| #define PALETTE_SIZE (PALETTE_COUNT * 3) |
| #define PALETTES_MAX 256 |
| #define PALT_TAG MKTAG('P', 'A', 'L', 'T') |
| #define VGA__TAG MKTAG('V', 'G', 'A', ' ') |
| static av_cold int xan_decode_end | ( | AVCodecContext * | avctx | ) | [static] |
| static int xan_decode_frame | ( | AVCodecContext * | avctx, | |
| void * | data, | |||
| int * | data_size, | |||
| AVPacket * | avpkt | |||
| ) | [static] |
| static av_cold int xan_decode_init | ( | AVCodecContext * | avctx | ) | [static] |
| static void xan_unpack | ( | unsigned char * | dest, | |
| int | dest_len, | |||
| const unsigned char * | src, | |||
| int | src_len | |||
| ) | [static] |
unpack simple compression
| dest | destination buffer of dest_len, must be padded with at least 130 bytes |
Definition at line 138 of file xan.c.
Referenced by xan_decode_chroma(), xan_decode_frame_type0(), and xan_wc3_decode_frame().
| static int xan_wc3_decode_frame | ( | XanContext * | s | ) | [static] |
| static void xan_wc3_output_pixel_run | ( | XanContext * | s, | |
| const unsigned char * | pixel_buffer, | |||
| int | x, | |||
| int | y, | |||
| int | pixel_count | |||
| ) | [inline, static] |
Initial value:
{
.name = "xan_wc3",
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_XAN_WC3,
.priv_data_size = sizeof(XanContext),
.init = xan_decode_init,
.close = xan_decode_end,
.decode = xan_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Wing Commander III / Xan"),
}
const uint8_t gamma_lookup[256] [static] |
This is a gamma correction that xan3 applies to all palette entries.
There is a peculiarity, namely that the values are clamped to 253 - it seems likely that this table was calculated by a buggy fixed-point implementation, the one above under RUNTIME_GAMMA behaves like this for example. The exponent value of 0.8 can be explained by this as well, since 0.8 = 4/5 and thus pow(x, 0.8) is still easy to calculate. Also, the input values are first rotated to the left by 2.
1.5.8