FFmpeg: libavcodec/eacmv.c Source File

FFmpeg

[フレーム]

libavcodec

eacmv.c

Go to the documentation of this file.

1 /*

2 * Electronic Arts CMV Video Decoder

4 *

5 * This file is part of FFmpeg.

6 *

7 * FFmpeg 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 * FFmpeg 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 FFmpeg; if not, write to the Free Software

19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

20 */

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 */

31 #include "libavutil/common.h"

32 #include "libavutil/intreadwrite.h"

33 #include "libavutil/imgutils.h"

34 #include "avcodec.h"

35 #include "internal.h"

37 typedef struct CmvContext {

38 AVCodecContext *avctx;

39 AVFrame *last_frame; ///< last

40 AVFrame *last2_frame; ///< second-last

41 int width, height;

42 unsigned int palette[AVPALETTE_COUNT];

43 } CmvContext;

45 static av_cold int cmv_decode_init(AVCodecContext *avctx){

46 CmvContext *s = avctx->priv_data;

48 s->avctx = avctx;

49 avctx->pix_fmt = AV_PIX_FMT_PAL8;

51 s->last_frame = av_frame_alloc();

52 s->last2_frame = av_frame_alloc();

53 if (!s->last_frame || !s->last2_frame) {

54 av_frame_free(&s->last_frame);

55 av_frame_free(&s->last2_frame);

56 return AVERROR(ENOMEM);

57 }

59 return 0;

60 }

62 static void cmv_decode_intra(CmvContext * s, AVFrame *frame,

63 const uint8_t *buf, const uint8_t *buf_end)

64 {

65 unsigned char *dst = frame->data[0];

66 int i;

68 for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {

69 memcpy(dst, buf, s->avctx->width);

70 dst += frame->linesize[0];

71 buf += s->avctx->width;

72 }

73 }

75 static void cmv_motcomp(unsigned char *dst, int dst_stride,

76 const unsigned char *src, int src_stride,

77 int x, int y,

78 int xoffset, int yoffset,

79 int width, int height){

80 int i,j;

82 for(j=y;j<y+4;j++)

83 for(i=x;i<x+4;i++)

84 {

85 if (i+xoffset>=0 && i+xoffset<width &&

86 j+yoffset>=0 && j+yoffset<height) {

87 dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];

88 }else{

89 dst[j*dst_stride + i] = 0;

90 }

91 }

92 }

94 static void cmv_decode_inter(CmvContext *s, AVFrame *frame, const uint8_t *buf,

95 const uint8_t *buf_end)

96 {

97 const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);

98 int x,y,i;

100 i = 0;

101 for(y=0; y<s->avctx->height/4; y++)

102 for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {

103 if (buf[i]==0xFF) {

104 unsigned char *dst = frame->data[0] + (y*4)*frame->linesize[0] + x*4;

105 if (raw+16<buf_end && *raw==0xFF) { /* intra */

106 raw++;

107 memcpy(dst, raw, 4);

108 memcpy(dst + frame->linesize[0], raw+4, 4);

109 memcpy(dst + 2 * frame->linesize[0], raw+8, 4);

110 memcpy(dst + 3 * frame->linesize[0], raw+12, 4);

111 raw+=16;

112 }else if(raw<buf_end) { /* inter using second-last frame as reference */

113 int xoffset = (*raw & 0xF) - 7;

114 int yoffset = ((*raw >> 4)) - 7;

115 if (s->last2_frame->data[0])

116 cmv_motcomp(frame->data[0], frame->linesize[0],

117 s->last2_frame->data[0], s->last2_frame->linesize[0],

118 x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);

119 raw++;

120 }

121 }else{ /* inter using last frame as reference */

122 int xoffset = (buf[i] & 0xF) - 7;

123 int yoffset = ((buf[i] >> 4)) - 7;

124 if (s->last_frame->data[0])

125 cmv_motcomp(frame->data[0], frame->linesize[0],

126 s->last_frame->data[0], s->last_frame->linesize[0],

127 x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);

128 }

129 i++;

130 }

131 }

132

133 static int cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)

134 {

135 int pal_start, pal_count, i, ret, fps;

136

137 if(buf_end - buf < 16) {

138 av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");

139 return AVERROR_INVALIDDATA;

140 }

141

142 s->width = AV_RL16(&buf[4]);

143 s->height = AV_RL16(&buf[6]);

144

145 if (s->width != s->avctx->width ||

146 s->height != s->avctx->height) {

147 av_frame_unref(s->last_frame);

148 av_frame_unref(s->last2_frame);

149 }

150

151 ret = ff_set_dimensions(s->avctx, s->width, s->height);

152 if (ret < 0)

153 return ret;

154

155 fps = AV_RL16(&buf[10]);

156 if (fps > 0)

157 s->avctx->time_base = (AVRational){ 1, fps };

158

159 pal_start = AV_RL16(&buf[12]);

160 pal_count = AV_RL16(&buf[14]);

161

162 buf += 16;

163 for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {

164 s->palette[i] = 0xFFU << 24 | AV_RB24(buf);

165 buf += 3;

166 }

167

168 return 0;

169 }

170

171 #define EA_PREAMBLE_SIZE 8

172 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')

173

174 static int cmv_decode_frame(AVCodecContext *avctx,

175 void *data, int *got_frame,

176 AVPacket *avpkt)

177 {

178 const uint8_t *buf = avpkt->data;

179 int buf_size = avpkt->size;

180 CmvContext *s = avctx->priv_data;

181 const uint8_t *buf_end = buf + buf_size;

182 AVFrame *frame = data;

183 int ret;

184

185 if (buf_end - buf < EA_PREAMBLE_SIZE)

186 return AVERROR_INVALIDDATA;

187

188 if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {

189 unsigned size = AV_RL32(buf + 4);

190 ret = cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);

191 if (ret < 0)

192 return ret;

193 if (size > buf_end - buf - EA_PREAMBLE_SIZE)

194 return -1;

195 buf += size;

196 }

197

198 if (av_image_check_size(s->width, s->height, 0, s->avctx))

199 return -1;

200

201 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)

202 return ret;

203

204 memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);

205

206 buf += EA_PREAMBLE_SIZE;

207 if ((buf[0]&1)) { // subtype

208 cmv_decode_inter(s, frame, buf+2, buf_end);

209 frame->key_frame = 0;

210 frame->pict_type = AV_PICTURE_TYPE_P;

211 }else{

212 frame->key_frame = 1;

213 frame->pict_type = AV_PICTURE_TYPE_I;

214 cmv_decode_intra(s, frame, buf+2, buf_end);

215 }

216

217 av_frame_unref(s->last2_frame);

218 av_frame_move_ref(s->last2_frame, s->last_frame);

219 if ((ret = av_frame_ref(s->last_frame, frame)) < 0)

220 return ret;

221

222 *got_frame = 1;

223

224 return buf_size;

225 }

226

227 static av_cold int cmv_decode_end(AVCodecContext *avctx){

228 CmvContext *s = avctx->priv_data;

229

230 av_frame_free(&s->last_frame);

231 av_frame_free(&s->last2_frame);

232

233 return 0;

234 }

235

236 AVCodec ff_eacmv_decoder = {

237 .name = "eacmv",

238 .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),

239 .type = AVMEDIA_TYPE_VIDEO,

240 .id = AV_CODEC_ID_CMV,

241 .priv_data_size = sizeof(CmvContext),

242 .init = cmv_decode_init,

243 .close = cmv_decode_end,

244 .decode = cmv_decode_frame,

245 .capabilities = CODEC_CAP_DR1,

246 };

Generated on Sun Sep 14 2014 18:55:54 for FFmpeg by doxygen 1.8.2