FFmpeg: libavcodec/qpeg.c Source File

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libavcodec

qpeg.c

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1 /*

2 * QPEG codec

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 Street, Fifth Floor, Boston, MA 02110-1301 USA

20 */

22 /**

23 * @file

24 * QPEG codec.

25 */

27 #include "avcodec.h"

28 #include "bytestream.h"

29 #include "internal.h"

31 typedef struct QpegContext{

32 AVCodecContext *avctx;

33 AVFrame pic, ref;

34 uint32_t pal[256];

35 GetByteContext buffer;

36 } QpegContext;

38 static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,

39 int stride, int width, int height)

40 {

41 int i;

42 int code;

43 int c0, c1;

44 int run, copy;

45 int filled = 0;

46 int rows_to_go;

48 rows_to_go = height;

49 height--;

50 dst = dst + height * stride;

52 while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (rows_to_go > 0)) {

53 code = bytestream2_get_byte(&qctx->buffer);

54 run = copy = 0;

55 if(code == 0xFC) /* end-of-picture code */

56 break;

57 if(code >= 0xF8) { /* very long run */

58 c0 = bytestream2_get_byte(&qctx->buffer);

59 c1 = bytestream2_get_byte(&qctx->buffer);

60 run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;

61 } else if (code >= 0xF0) { /* long run */

62 c0 = bytestream2_get_byte(&qctx->buffer);

63 run = ((code & 0xF) << 8) + c0 + 2;

64 } else if (code >= 0xE0) { /* short run */

65 run = (code & 0x1F) + 2;

66 } else if (code >= 0xC0) { /* very long copy */

67 c0 = bytestream2_get_byte(&qctx->buffer);

68 c1 = bytestream2_get_byte(&qctx->buffer);

69 copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;

70 } else if (code >= 0x80) { /* long copy */

71 c0 = bytestream2_get_byte(&qctx->buffer);

72 copy = ((code & 0x7F) << 8) + c0 + 1;

73 } else { /* short copy */

74 copy = code + 1;

75 }

77 /* perform actual run or copy */

78 if(run) {

79 int p;

81 p = bytestream2_get_byte(&qctx->buffer);

82 for(i = 0; i < run; i++) {

83 dst[filled++] = p;

84 if (filled >= width) {

85 filled = 0;

86 dst -= stride;

87 rows_to_go--;

88 if(rows_to_go <= 0)

89 break;

90 }

91 }

92 } else {

93 for(i = 0; i < copy; i++) {

94 dst[filled++] = bytestream2_get_byte(&qctx->buffer);

95 if (filled >= width) {

96 filled = 0;

97 dst -= stride;

98 rows_to_go--;

99 if(rows_to_go <= 0)

100 break;

101 }

102 }

103 }

104 }

105 }

106

107 static const int qpeg_table_h[16] =

108 { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};

109 static const int qpeg_table_w[16] =

110 { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};

111

112 /* Decodes delta frames */

113 static void qpeg_decode_inter(QpegContext *qctx, uint8_t *dst,

114 int stride, int width, int height,

115 int delta, const uint8_t *ctable,

116 uint8_t *refdata)

117 {

118 int i, j;

119 int code;

120 int filled = 0;

121 int orig_height;

122

123 if(!refdata)

124 refdata= dst;

125

126 /* copy prev frame */

127 for(i = 0; i < height; i++)

128 memcpy(dst + (i * stride), refdata + (i * stride), width);

129

130 orig_height = height;

131 height--;

132 dst = dst + height * stride;

133

134 while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (height >= 0)) {

135 code = bytestream2_get_byte(&qctx->buffer);

136

137 if(delta) {

138 /* motion compensation */

139 while(bytestream2_get_bytes_left(&qctx->buffer) > 0 && (code & 0xF0) == 0xF0) {

140 if(delta == 1) {

141 int me_idx;

142 int me_w, me_h, me_x, me_y;

143 uint8_t *me_plane;

144 int corr, val;

145

146 /* get block size by index */

147 me_idx = code & 0xF;

148 me_w = qpeg_table_w[me_idx];

149 me_h = qpeg_table_h[me_idx];

150

151 /* extract motion vector */

152 corr = bytestream2_get_byte(&qctx->buffer);

153

154 val = corr >> 4;

155 if(val > 7)

156 val -= 16;

157 me_x = val;

158

159 val = corr & 0xF;

160 if(val > 7)

161 val -= 16;

162 me_y = val;

163

164 /* check motion vector */

165 if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||

166 (height - me_y - me_h < 0) || (height - me_y > orig_height) ||

167 (filled + me_w > width) || (height - me_h < 0))

168 av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",

169 me_x, me_y, me_w, me_h, filled, height);

170 else {

171 /* do motion compensation */

172 me_plane = refdata + (filled + me_x) + (height - me_y) * stride;

173 for(j = 0; j < me_h; j++) {

174 for(i = 0; i < me_w; i++)

175 dst[filled + i - (j * stride)] = me_plane[i - (j * stride)];

176 }

177 }

178 }

179 code = bytestream2_get_byte(&qctx->buffer);

180 }

181 }

182

183 if(code == 0xE0) /* end-of-picture code */

184 break;

185 if(code > 0xE0) { /* run code: 0xE1..0xFF */

186 int p;

187

188 code &= 0x1F;

189 p = bytestream2_get_byte(&qctx->buffer);

190 for(i = 0; i <= code; i++) {

191 dst[filled++] = p;

192 if(filled >= width) {

193 filled = 0;

194 dst -= stride;

195 height--;

196 if(height < 0)

197 break;

198 }

199 }

200 } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */

201 code &= 0x1F;

202

203 if(code + 1 > bytestream2_get_bytes_left(&qctx->buffer))

204 break;

205

206 for(i = 0; i <= code; i++) {

207 dst[filled++] = bytestream2_get_byte(&qctx->buffer);

208 if(filled >= width) {

209 filled = 0;

210 dst -= stride;

211 height--;

212 if(height < 0)

213 break;

214 }

215 }

216 } else if(code >= 0x80) { /* skip code: 0x80..0xBF */

217 int skip;

218

219 code &= 0x3F;

220 /* codes 0x80 and 0x81 are actually escape codes,

221 skip value minus constant is in the next byte */

222 if(!code)

223 skip = bytestream2_get_byte(&qctx->buffer) + 64;

224 else if(code == 1)

225 skip = bytestream2_get_byte(&qctx->buffer) + 320;

226 else

227 skip = code;

228 filled += skip;

229 while( filled >= width) {

230 filled -= width;

231 dst -= stride;

232 height--;

233 if(height < 0)

234 break;

235 }

236 } else {

237 /* zero code treated as one-pixel skip */

238 if(code) {

239 dst[filled++] = ctable[code & 0x7F];

240 }

241 else

242 filled++;

243 if(filled >= width) {

244 filled = 0;

245 dst -= stride;

246 height--;

247 }

248 }

249 }

250 }

251

252 static int decode_frame(AVCodecContext *avctx,

253 void *data, int *got_frame,

254 AVPacket *avpkt)

255 {

256 uint8_t ctable[128];

257 QpegContext * const a = avctx->priv_data;

258 AVFrame * p = &a->pic;

259 AVFrame * ref= &a->ref;

260 uint8_t* outdata;

261 int delta, ret;

262 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);

263

264 if (avpkt->size < 0x86) {

265 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

266 return AVERROR_INVALIDDATA;

267 }

268

269 bytestream2_init(&a->buffer, avpkt->data, avpkt->size);

270

271 av_frame_unref(ref);

272 av_frame_move_ref(ref, p);

273

274 if ((ret = ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF)) < 0)

275 return ret;

276 outdata = a->pic.data[0];

277 bytestream2_skip(&a->buffer, 4);

278 bytestream2_get_buffer(&a->buffer, ctable, 128);

279 bytestream2_skip(&a->buffer, 1);

280

281 delta = bytestream2_get_byte(&a->buffer);

282 if(delta == 0x10) {

283 qpeg_decode_intra(a, outdata, a->pic.linesize[0], avctx->width, avctx->height);

284 } else {

285 qpeg_decode_inter(a, outdata, a->pic.linesize[0], avctx->width, avctx->height, delta, ctable, a->ref.data[0]);

286 }

287

288 /* make the palette available on the way out */

289 if (pal) {

290 a->pic.palette_has_changed = 1;

291 memcpy(a->pal, pal, AVPALETTE_SIZE);

292 }

293 memcpy(a->pic.data[1], a->pal, AVPALETTE_SIZE);

294

295 if ((ret = av_frame_ref(data, &a->pic)) < 0)

296 return ret;

297

298 *got_frame = 1;

299

300 return avpkt->size;

301 }

302

303 static void decode_flush(AVCodecContext *avctx){

304 QpegContext * const a = avctx->priv_data;

305 int i, pal_size;

306 const uint8_t *pal_src;

307

308 pal_size = FFMIN(1024U, avctx->extradata_size);

309 pal_src = avctx->extradata + avctx->extradata_size - pal_size;

310

311 for (i=0; i<pal_size/4; i++)

312 a->pal[i] = 0xFFU<<24 | AV_RL32(pal_src+4*i);

313 }

314

315 static av_cold int decode_init(AVCodecContext *avctx){

316 QpegContext * const a = avctx->priv_data;

317

318 avcodec_get_frame_defaults(&a->pic);

319 avcodec_get_frame_defaults(&a->ref);

320 a->avctx = avctx;

321 avctx->pix_fmt= AV_PIX_FMT_PAL8;

322

323 decode_flush(avctx);

324

325 avcodec_get_frame_defaults(&a->pic);

326

327 return 0;

328 }

329

330 static av_cold int decode_end(AVCodecContext *avctx){

331 QpegContext * const a = avctx->priv_data;

332 AVFrame * const p = &a->pic;

333 AVFrame * const ref= &a->ref;

334

335 av_frame_unref(p);

336 av_frame_unref(ref);

337

338 return 0;

339 }

340

341 AVCodec ff_qpeg_decoder = {

342 .name = "qpeg",

343 .type = AVMEDIA_TYPE_VIDEO,

344 .id = AV_CODEC_ID_QPEG,

345 .priv_data_size = sizeof(QpegContext),

346 .init = decode_init,

347 .close = decode_end,

348 .decode = decode_frame,

349 .flush = decode_flush,

350 .capabilities = CODEC_CAP_DR1,

351 .long_name = NULL_IF_CONFIG_SMALL("Q-team QPEG"),

352 };

Generated on Wed Jul 10 2013 23:48:04 for FFmpeg by doxygen 1.8.2