FFmpeg: libavcodec/mdec.c Source File

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libavcodec

mdec.c

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1 /*

2 * Sony PlayStation MDEC (Motion DECoder)

4 *

5 * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>

6 *

7 * This file is part of FFmpeg.

8 *

9 * FFmpeg is free software; you can redistribute it and/or

10 * modify it under the terms of the GNU Lesser General Public

11 * License as published by the Free Software Foundation; either

12 * version 2.1 of the License, or (at your option) any later version.

13 *

14 * FFmpeg is distributed in the hope that it will be useful,

15 * but WITHOUT ANY WARRANTY; without even the implied warranty of

16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

17 * Lesser General Public License for more details.

18 *

19 * You should have received a copy of the GNU Lesser General Public

20 * License along with FFmpeg; if not, write to the Free Software

21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

22 */

24 /**

25 * @file

26 * Sony PlayStation MDEC (Motion DECoder)

27 * This is very similar to intra-only MPEG-1.

28 */

30 #include "avcodec.h"

31 #include "mpegvideo.h"

32 #include "mpeg12.h"

33 #include "thread.h"

35 typedef struct MDECContext {

36 AVCodecContext *avctx;

37 DSPContext dsp;

38 ThreadFrame frame;

39 GetBitContext gb;

40 ScanTable scantable;

41 int version;

42 int qscale;

43 int last_dc[3];

44 int mb_width;

45 int mb_height;

46 int mb_x, mb_y;

47 DECLARE_ALIGNED(16, int16_t, block)[6][64];

48 uint8_t *bitstream_buffer;

49 unsigned int bitstream_buffer_size;

50 int block_last_index[6];

51 } MDECContext;

53 //very similar to MPEG-1

54 static inline int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n)

55 {

56 int level, diff, i, j, run;

57 int component;

58 RLTable *rl = &ff_rl_mpeg1;

59 uint8_t * const scantable = a->scantable.permutated;

60 const uint16_t *quant_matrix = ff_mpeg1_default_intra_matrix;

61 const int qscale = a->qscale;

63 /* DC coefficient */

64 if (a->version == 2) {

65 block[0] = 2 * get_sbits(&a->gb, 10) + 1024;

66 } else {

67 component = (n <= 3 ? 0 : n - 4 + 1);

68 diff = decode_dc(&a->gb, component);

69 if (diff >= 0xffff)

70 return AVERROR_INVALIDDATA;

71 a->last_dc[component] += diff;

72 block[0] = a->last_dc[component] << 3;

73 }

75 i = 0;

76 {

77 OPEN_READER(re, &a->gb);

78 /* now quantify & encode AC coefficients */

79 for (;;) {

80 UPDATE_CACHE(re, &a->gb);

81 GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

83 if (level == 127) {

84 break;

85 } else if (level != 0) {

86 i += run;

87 j = scantable[i];

88 level = (level * qscale * quant_matrix[j]) >> 3;

89 level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);

90 LAST_SKIP_BITS(re, &a->gb, 1);

91 } else {

92 /* escape */

93 run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);

94 UPDATE_CACHE(re, &a->gb);

95 level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);

96 i += run;

97 j = scantable[i];

98 if (level < 0) {

99 level = -level;

100 level = (level * qscale * quant_matrix[j]) >> 3;

101 level = (level - 1) | 1;

102 level = -level;

103 } else {

104 level = (level * qscale * quant_matrix[j]) >> 3;

105 level = (level - 1) | 1;

106 }

107 }

108 if (i > 63) {

109 av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);

110 return AVERROR_INVALIDDATA;

111 }

112

113 block[j] = level;

114 }

115 CLOSE_READER(re, &a->gb);

116 }

117 a->block_last_index[n] = i;

118 return 0;

119 }

120

121 static inline int decode_mb(MDECContext *a, int16_t block[6][64])

122 {

123 int i, ret;

124 static const int block_index[6] = { 5, 4, 0, 1, 2, 3 };

125

126 a->dsp.clear_blocks(block[0]);

127

128 for (i = 0; i < 6; i++) {

129 if ((ret = mdec_decode_block_intra(a, block[block_index[i]],

130 block_index[i])) < 0)

131 return ret;

132 if (get_bits_left(&a->gb) < 0)

133 return AVERROR_INVALIDDATA;

134 }

135 return 0;

136 }

137

138 static inline void idct_put(MDECContext *a, AVFrame *frame, int mb_x, int mb_y)

139 {

140 int16_t (*block)[64] = a->block;

141 int linesize = frame->linesize[0];

142

143 uint8_t *dest_y = frame->data[0] + (mb_y * 16* linesize ) + mb_x * 16;

144 uint8_t *dest_cb = frame->data[1] + (mb_y * 8 * frame->linesize[1]) + mb_x * 8;

145 uint8_t *dest_cr = frame->data[2] + (mb_y * 8 * frame->linesize[2]) + mb_x * 8;

146

147 a->dsp.idct_put(dest_y, linesize, block[0]);

148 a->dsp.idct_put(dest_y + 8, linesize, block[1]);

149 a->dsp.idct_put(dest_y + 8 * linesize, linesize, block[2]);

150 a->dsp.idct_put(dest_y + 8 * linesize + 8, linesize, block[3]);

151

152 if (!(a->avctx->flags & CODEC_FLAG_GRAY)) {

153 a->dsp.idct_put(dest_cb, frame->linesize[1], block[4]);

154 a->dsp.idct_put(dest_cr, frame->linesize[2], block[5]);

155 }

156 }

157

158 static int decode_frame(AVCodecContext *avctx,

159 void *data, int *got_frame,

160 AVPacket *avpkt)

161 {

162 MDECContext * const a = avctx->priv_data;

163 const uint8_t *buf = avpkt->data;

164 int buf_size = avpkt->size;

165 ThreadFrame frame = { .f = data };

166 int i, ret;

167

168 if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)

169 return ret;

170 frame.f->pict_type = AV_PICTURE_TYPE_I;

171 frame.f->key_frame = 1;

172

173 av_fast_malloc(&a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);

174 if (!a->bitstream_buffer)

175 return AVERROR(ENOMEM);

176 for (i = 0; i < buf_size; i += 2) {

177 a->bitstream_buffer[i] = buf[i + 1];

178 a->bitstream_buffer[i + 1] = buf[i];

179 }

180 if ((ret = init_get_bits8(&a->gb, a->bitstream_buffer, buf_size)) < 0)

181 return ret;

182

183 /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */

184 skip_bits(&a->gb, 32);

185

186 a->qscale = get_bits(&a->gb, 16);

187 a->version = get_bits(&a->gb, 16);

188

189 a->last_dc[0] = a->last_dc[1] = a->last_dc[2] = 128;

190

191 for (a->mb_x = 0; a->mb_x < a->mb_width; a->mb_x++) {

192 for (a->mb_y = 0; a->mb_y < a->mb_height; a->mb_y++) {

193 if ((ret = decode_mb(a, a->block)) < 0)

194 return ret;

195

196 idct_put(a, frame.f, a->mb_x, a->mb_y);

197 }

198 }

199

200 *got_frame = 1;

201

202 return (get_bits_count(&a->gb) + 31) / 32 * 4;

203 }

204

205 static av_cold int decode_init(AVCodecContext *avctx)

206 {

207 MDECContext * const a = avctx->priv_data;

208

209 a->mb_width = (avctx->coded_width + 15) / 16;

210 a->mb_height = (avctx->coded_height + 15) / 16;

211

212 a->avctx = avctx;

213

214 ff_dsputil_init(&a->dsp, avctx);

215 ff_mpeg12_init_vlcs();

216 ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);

217

218 if (avctx->idct_algo == FF_IDCT_AUTO)

219 avctx->idct_algo = FF_IDCT_SIMPLE;

220 avctx->pix_fmt = AV_PIX_FMT_YUVJ420P;

221

222 return 0;

223 }

224

225 static av_cold int decode_init_thread_copy(AVCodecContext *avctx)

226 {

227 MDECContext * const a = avctx->priv_data;

228

229 a->avctx = avctx;

230

231 return 0;

232 }

233

234 static av_cold int decode_end(AVCodecContext *avctx)

235 {

236 MDECContext * const a = avctx->priv_data;

237

238 av_freep(&a->bitstream_buffer);

239 a->bitstream_buffer_size = 0;

240

241 return 0;

242 }

243

244 AVCodec ff_mdec_decoder = {

245 .name = "mdec",

246 .long_name = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),

247 .type = AVMEDIA_TYPE_VIDEO,

248 .id = AV_CODEC_ID_MDEC,

249 .priv_data_size = sizeof(MDECContext),

250 .init = decode_init,

251 .close = decode_end,

252 .decode = decode_frame,

253 .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,

254 .init_thread_copy = ONLY_IF_THREADS_ENABLED(decode_init_thread_copy)

255 };

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