id Quake II Cin Video Decoder by Dr. More...
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Data Structures | |
struct | hnode |
struct | IdcinContext |
Macros | |
#define | HUFFMAN_TABLE_SIZE 64 * 1024 |
#define | HUF_TOKENS 256 |
#define | PALETTE_COUNT 256 |
Typedefs | |
typedef struct IdcinContext | IdcinContext |
Functions | |
static int | huff_smallest_node (hnode *hnodes, int num_hnodes) |
static av_cold void | huff_build_tree (IdcinContext *s, int prev) |
static av_cold int | idcin_decode_init (AVCodecContext *avctx) |
static void | idcin_decode_vlcs (IdcinContext *s) |
static int | idcin_decode_frame (AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) |
static av_cold int | idcin_decode_end (AVCodecContext *avctx) |
Variables | |
AVCodec | ff_idcin_decoder |
id Quake II Cin Video Decoder by Dr.
Tim Ferguson For more information about the id CIN format, visit: http://www.csse.monash.edu.au/~timf/
This video decoder outputs PAL8 colorspace data. Interacting with this decoder is a little involved. During initialization, the demuxer must transmit the 65536-byte Huffman table(s) to the decoder via extradata. Then, whenever a palette change is encountered while demuxing the file, the demuxer must use the same extradata space to transmit an AVPaletteControl structure.
id CIN video is purely Huffman-coded, intraframe-only codec. It achieves a little more compression by exploiting the fact that adjacent pixels tend to be similar.
Note that this decoder could use libavcodec's optimized VLC facilities rather than naive, tree-based Huffman decoding. However, there are 256 Huffman tables. Plus, the VLC bit coding order is right -> left instead or left -> right, so all of the bits would have to be reversed. Further, the original Quake II implementation likely used a similar naive decoding algorithm and it worked fine on much lower spec machines.
Definition in file idcinvideo.c.
#define HUF_TOKENS 256 |
Definition at line 54 of file idcinvideo.c.
Referenced by huff_build_tree(), idcin_decode_init(), and idcin_decode_vlcs().
#define HUFFMAN_TABLE_SIZE 64 * 1024 |
Definition at line 53 of file idcinvideo.c.
Referenced by idcin_decode_init().
#define PALETTE_COUNT 256 |
Definition at line 55 of file idcinvideo.c.
typedef struct IdcinContext IdcinContext |
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Definition at line 116 of file idcinvideo.c.
Referenced by idcin_decode_init().
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Definition at line 84 of file idcinvideo.c.
Referenced by huff_build_tree().
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Definition at line 246 of file idcinvideo.c.
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Definition at line 210 of file idcinvideo.c.
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Definition at line 146 of file idcinvideo.c.
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Definition at line 174 of file idcinvideo.c.
Referenced by idcin_decode_frame().
AVCodec ff_idcin_decoder |
Definition at line 256 of file idcinvideo.c.