1/*
2 * Electronic Arts CMV Video Decoder
3 * Copyright (c) 2007-2008 Peter Ross
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
20 */
21
22/**
23 * @file
24 * Electronic Arts CMV Video Decoder
25 * by Peter Ross (pross@xvid.org)
26 *
27 * Technical details here:
28 * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_CMV
29 */
30
31#include "libavutil/intreadwrite.h"
32#include "libavutil/imgutils.h"
33#include "avcodec.h"
34
35typedef struct CmvContext {
36    AVCodecContext *avctx;
37    AVFrame frame;        ///< current
38    AVFrame last_frame;   ///< last
39    AVFrame last2_frame;  ///< second-last
40    int width, height;
41    unsigned int palette[AVPALETTE_COUNT];
42} CmvContext;
43
44static av_cold int cmv_decode_init(AVCodecContext *avctx){
45    CmvContext *s = avctx->priv_data;
46    s->avctx = avctx;
47    avctx->pix_fmt = PIX_FMT_PAL8;
48    return 0;
49}
50
51static void cmv_decode_intra(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
52    unsigned char *dst = s->frame.data[0];
53    int i;
54
55    for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {
56        memcpy(dst, buf, s->avctx->width);
57        dst += s->frame.linesize[0];
58        buf += s->avctx->width;
59    }
60}
61
62static void cmv_motcomp(unsigned char *dst, int dst_stride,
63                        const unsigned char *src, int src_stride,
64                        int x, int y,
65                        int xoffset, int yoffset,
66                        int width, int height){
67    int i,j;
68
69    for(j=y;j<y+4;j++)
70    for(i=x;i<x+4;i++)
71    {
72        if (i+xoffset>=0 && i+xoffset<width &&
73            j+yoffset>=0 && j+yoffset<height) {
74            dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
75        }else{
76            dst[j*dst_stride + i] = 0;
77        }
78    }
79}
80
81static void cmv_decode_inter(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
82    const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
83    int x,y,i;
84
85    i = 0;
86    for(y=0; y<s->avctx->height/4; y++)
87    for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {
88        if (buf[i]==0xFF) {
89            unsigned char *dst = s->frame.data[0] + (y*4)*s->frame.linesize[0] + x*4;
90            if (raw+16<buf_end && *raw==0xFF) { /* intra */
91                raw++;
92                memcpy(dst, raw, 4);
93                memcpy(dst+s->frame.linesize[0], raw+4, 4);
94                memcpy(dst+2*s->frame.linesize[0], raw+8, 4);
95                memcpy(dst+3*s->frame.linesize[0], raw+12, 4);
96                raw+=16;
97            }else if(raw<buf_end) {  /* inter using second-last frame as reference */
98                int xoffset = (*raw & 0xF) - 7;
99                int yoffset = ((*raw >> 4)) - 7;
100                if (s->last2_frame.data[0])
101                    cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
102                                s->last2_frame.data[0], s->last2_frame.linesize[0],
103                                x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
104                raw++;
105            }
106        }else{  /* inter using last frame as reference */
107            int xoffset = (buf[i] & 0xF) - 7;
108            int yoffset = ((buf[i] >> 4)) - 7;
109            cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
110                      s->last_frame.data[0], s->last_frame.linesize[0],
111                      x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
112        }
113        i++;
114    }
115}
116
117static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
118{
119    int pal_start, pal_count, i;
120
121    if(buf_end - buf < 16) {
122        av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
123        return;
124    }
125
126    s->width  = AV_RL16(&buf[4]);
127    s->height = AV_RL16(&buf[6]);
128    if (s->avctx->width!=s->width || s->avctx->height!=s->height)
129        avcodec_set_dimensions(s->avctx, s->width, s->height);
130
131    s->avctx->time_base.num = 1;
132    s->avctx->time_base.den = AV_RL16(&buf[10]);
133
134    pal_start = AV_RL16(&buf[12]);
135    pal_count = AV_RL16(&buf[14]);
136
137    buf += 16;
138    for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
139        s->palette[i] = AV_RB24(buf);
140        buf += 3;
141    }
142}
143
144#define EA_PREAMBLE_SIZE 8
145#define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
146
147static int cmv_decode_frame(AVCodecContext *avctx,
148                            void *data, int *data_size,
149                            AVPacket *avpkt)
150{
151    const uint8_t *buf = avpkt->data;
152    int buf_size = avpkt->size;
153    CmvContext *s = avctx->priv_data;
154    const uint8_t *buf_end = buf + buf_size;
155
156    if (buf_end - buf < EA_PREAMBLE_SIZE)
157        return AVERROR_INVALIDDATA;
158
159    if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
160        cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
161        return buf_size;
162    }
163
164    if (av_image_check_size(s->width, s->height, 0, s->avctx))
165        return -1;
166
167    /* shuffle */
168    if (s->last2_frame.data[0])
169        avctx->release_buffer(avctx, &s->last2_frame);
170    FFSWAP(AVFrame, s->last_frame, s->last2_frame);
171    FFSWAP(AVFrame, s->frame, s->last_frame);
172
173    s->frame.reference = 1;
174    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
175    if (avctx->get_buffer(avctx, &s->frame)<0) {
176        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
177        return -1;
178    }
179
180    memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
181
182    buf += EA_PREAMBLE_SIZE;
183    if ((buf[0]&1)) {  // subtype
184        cmv_decode_inter(s, buf+2, buf_end);
185        s->frame.key_frame = 0;
186        s->frame.pict_type = AV_PICTURE_TYPE_P;
187    }else{
188        s->frame.key_frame = 1;
189        s->frame.pict_type = AV_PICTURE_TYPE_I;
190        cmv_decode_intra(s, buf+2, buf_end);
191    }
192
193    *data_size = sizeof(AVFrame);
194    *(AVFrame*)data = s->frame;
195
196    return buf_size;
197}
198
199static av_cold int cmv_decode_end(AVCodecContext *avctx){
200    CmvContext *s = avctx->priv_data;
201    if (s->frame.data[0])
202        s->avctx->release_buffer(avctx, &s->frame);
203    if (s->last_frame.data[0])
204        s->avctx->release_buffer(avctx, &s->last_frame);
205    if (s->last2_frame.data[0])
206        s->avctx->release_buffer(avctx, &s->last2_frame);
207
208    return 0;
209}
210
211AVCodec ff_eacmv_decoder = {
212    .name           = "eacmv",
213    .type           = AVMEDIA_TYPE_VIDEO,
214    .id             = CODEC_ID_CMV,
215    .priv_data_size = sizeof(CmvContext),
216    .init           = cmv_decode_init,
217    .close          = cmv_decode_end,
218    .decode         = cmv_decode_frame,
219    .capabilities   = CODEC_CAP_DR1,
220    .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
221};
222