aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/cyuv.c
blob: b64e1a58bf732ef357f5813346c960d02dda7f9e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
/*
 *
 * Copyright (C) 2003 the ffmpeg project
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Creative YUV (CYUV) Video Decoder
 *   by Mike Melanson (melanson@pcisys.net)
 * based on "Creative YUV (CYUV) stream format for AVI":
 *   http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
 *
 */

/**
 * @file cyuv.c
 * Creative YUV (CYUV) Video Decoder.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "common.h"
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"


typedef struct CyuvDecodeContext {
    AVCodecContext *avctx;
    int width, height;
    AVFrame frame;
} CyuvDecodeContext;

static int cyuv_decode_init(AVCodecContext *avctx)
{
    CyuvDecodeContext *s = avctx->priv_data;

    s->avctx = avctx;
    s->width = avctx->width;
    /* width needs to be divisible by 4 for this codec to work */
    if (s->width & 0x3)
        return -1;
    s->height = avctx->height;
    avctx->pix_fmt = PIX_FMT_YUV411P;
    avctx->has_b_frames = 0;

    return 0;
}

static int cyuv_decode_frame(AVCodecContext *avctx,
                             void *data, int *data_size,
                             uint8_t *buf, int buf_size)
{
    CyuvDecodeContext *s=avctx->priv_data;

    unsigned char *y_plane;
    unsigned char *u_plane;
    unsigned char *v_plane;
    int y_ptr;
    int u_ptr;
    int v_ptr;

    /* prediction error tables (make it clear that they are signed values) */
    signed char *y_table = buf +  0;
    signed char *u_table = buf + 16;
    signed char *v_table = buf + 32;

    unsigned char y_pred, u_pred, v_pred;
    int stream_ptr;
    unsigned char cur_byte;
    int pixel_groups;

    /* sanity check the buffer size: A buffer has 3x16-bytes tables
     * followed by (height) lines each with 3 bytes to represent groups
     * of 4 pixels. Thus, the total size of the buffer ought to be:
     *    (3 * 16) + height * (width * 3 / 4) */
    if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
      av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
        buf_size,
        48 + s->height * (s->width * 3 / 4));
      return -1;
    }

    /* pixel data starts 48 bytes in, after 3x16-byte tables */
    stream_ptr = 48;

    if(s->frame.data[0])
        avctx->release_buffer(avctx, &s->frame);

    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
    s->frame.reference = 0;
    if(avctx->get_buffer(avctx, &s->frame) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }

    y_plane = s->frame.data[0];
    u_plane = s->frame.data[1];
    v_plane = s->frame.data[2];

    /* iterate through each line in the height */
    for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
         y_ptr < (s->height * s->frame.linesize[0]);
         y_ptr += s->frame.linesize[0] - s->width,
         u_ptr += s->frame.linesize[1] - s->width / 4,
         v_ptr += s->frame.linesize[2] - s->width / 4) {

        /* reset predictors */
        cur_byte = buf[stream_ptr++];
        u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
        y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;

        cur_byte = buf[stream_ptr++];
        v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
        y_pred += y_table[cur_byte & 0x0F];
        y_plane[y_ptr++] = y_pred;

        cur_byte = buf[stream_ptr++];
        y_pred += y_table[cur_byte & 0x0F];
        y_plane[y_ptr++] = y_pred;
        y_pred += y_table[(cur_byte & 0xF0) >> 4];
        y_plane[y_ptr++] = y_pred;

        /* iterate through the remaining pixel groups (4 pixels/group) */
        pixel_groups = s->width / 4 - 1;
        while (pixel_groups--) {

            cur_byte = buf[stream_ptr++];
            u_pred += u_table[(cur_byte & 0xF0) >> 4];
            u_plane[u_ptr++] = u_pred;
            y_pred += y_table[cur_byte & 0x0F];
            y_plane[y_ptr++] = y_pred;

            cur_byte = buf[stream_ptr++];
            v_pred += v_table[(cur_byte & 0xF0) >> 4];
            v_plane[v_ptr++] = v_pred;
            y_pred += y_table[cur_byte & 0x0F];
            y_plane[y_ptr++] = y_pred;

            cur_byte = buf[stream_ptr++];
            y_pred += y_table[cur_byte & 0x0F];
            y_plane[y_ptr++] = y_pred;
            y_pred += y_table[(cur_byte & 0xF0) >> 4];
            y_plane[y_ptr++] = y_pred;

        }
    }

    *data_size=sizeof(AVFrame);
    *(AVFrame*)data= s->frame;

    return buf_size;
}

static int cyuv_decode_end(AVCodecContext *avctx)
{
/*    CyuvDecodeContext *s = avctx->priv_data;*/

    return 0;
}

AVCodec cyuv_decoder = {
    "cyuv",
    CODEC_TYPE_VIDEO,
    CODEC_ID_CYUV,
    sizeof(CyuvDecodeContext),
    cyuv_decode_init,
    NULL,
    cyuv_decode_end,
    cyuv_decode_frame,
    CODEC_CAP_DR1,
    NULL
};