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00022 #include "avcodec.h"
00023 #include "internal.h"
00024 #include "bytestream.h"
00025
00026 enum BMVFlags{
00027 BMV_NOP = 0,
00028 BMV_END,
00029 BMV_DELTA,
00030 BMV_INTRA,
00031
00032 BMV_SCROLL = 0x04,
00033 BMV_PALETTE = 0x08,
00034 BMV_COMMAND = 0x10,
00035 BMV_AUDIO = 0x20,
00036 BMV_EXT = 0x40,
00037 BMV_PRINT = 0x80
00038 };
00039
00040 #define SCREEN_WIDE 640
00041 #define SCREEN_HIGH 429
00042
00043 typedef struct BMVDecContext {
00044 AVCodecContext *avctx;
00045 AVFrame pic;
00046
00047 uint8_t *frame, frame_base[SCREEN_WIDE * (SCREEN_HIGH + 1)];
00048 uint32_t pal[256];
00049 const uint8_t *stream;
00050 } BMVDecContext;
00051
00052 #define NEXT_BYTE(v) v = forward ? v + 1 : v - 1;
00053
00054 static int decode_bmv_frame(const uint8_t *source, int src_len, uint8_t *frame, int frame_off)
00055 {
00056 int val, saved_val = 0;
00057 int tmplen = src_len;
00058 const uint8_t *src, *source_end = source + src_len;
00059 uint8_t *frame_end = frame + SCREEN_WIDE * SCREEN_HIGH;
00060 uint8_t *dst, *dst_end;
00061 int len, mask;
00062 int forward = (frame_off <= -SCREEN_WIDE) || (frame_off >= 0);
00063 int read_two_nibbles, flag;
00064 int advance_mode;
00065 int mode = 0;
00066 int i;
00067
00068 if (src_len <= 0)
00069 return -1;
00070
00071 if (forward) {
00072 src = source;
00073 dst = frame;
00074 dst_end = frame_end;
00075 } else {
00076 src = source + src_len - 1;
00077 dst = frame_end - 1;
00078 dst_end = frame - 1;
00079 }
00080 for (;;) {
00081 int shift = 0;
00082 flag = 0;
00083
00084
00085
00086
00087
00088
00089
00090
00091 if (!mode || (tmplen == 4)) {
00092 if (src < source || src >= source_end)
00093 return -1;
00094 val = *src;
00095 read_two_nibbles = 1;
00096 } else {
00097 val = saved_val;
00098 read_two_nibbles = 0;
00099 }
00100 if (!(val & 0xC)) {
00101 for (;;) {
00102 if (!read_two_nibbles) {
00103 if (src < source || src >= source_end)
00104 return -1;
00105 shift += 2;
00106 val |= *src << shift;
00107 if (*src & 0xC)
00108 break;
00109 }
00110
00111
00112 read_two_nibbles = 0;
00113 shift += 2;
00114 mask = (1 << shift) - 1;
00115 val = ((val >> 2) & ~mask) | (val & mask);
00116 NEXT_BYTE(src);
00117 if ((val & (0xC << shift))) {
00118 flag = 1;
00119 break;
00120 }
00121 }
00122 } else if (mode) {
00123 flag = tmplen != 4;
00124 }
00125 if (flag) {
00126 tmplen = 4;
00127 } else {
00128 saved_val = val >> (4 + shift);
00129 tmplen = 0;
00130 val &= (1 << (shift + 4)) - 1;
00131 NEXT_BYTE(src);
00132 }
00133 advance_mode = val & 1;
00134 len = (val >> 1) - 1;
00135 mode += 1 + advance_mode;
00136 if (mode >= 4)
00137 mode -= 3;
00138 if (len <= 0 || FFABS(dst_end - dst) < len)
00139 return -1;
00140 switch (mode) {
00141 case 1:
00142 if (forward) {
00143 if (dst - frame + SCREEN_WIDE < frame_off ||
00144 frame_end - dst < frame_off + len)
00145 return -1;
00146 for (i = 0; i < len; i++)
00147 dst[i] = dst[frame_off + i];
00148 dst += len;
00149 } else {
00150 dst -= len;
00151 if (dst - frame + SCREEN_WIDE < frame_off ||
00152 frame_end - dst < frame_off + len)
00153 return -1;
00154 for (i = len - 1; i >= 0; i--)
00155 dst[i] = dst[frame_off + i];
00156 }
00157 break;
00158 case 2:
00159 if (forward) {
00160 if (source + src_len - src < len)
00161 return -1;
00162 memcpy(dst, src, len);
00163 dst += len;
00164 src += len;
00165 } else {
00166 if (src - source < len)
00167 return -1;
00168 dst -= len;
00169 src -= len;
00170 memcpy(dst, src, len);
00171 }
00172 break;
00173 case 3:
00174 val = forward ? dst[-1] : dst[1];
00175 if (forward) {
00176 memset(dst, val, len);
00177 dst += len;
00178 } else {
00179 dst -= len;
00180 memset(dst, val, len);
00181 }
00182 break;
00183 default:
00184 break;
00185 }
00186 if (dst == dst_end)
00187 return 0;
00188 }
00189 return 0;
00190 }
00191
00192 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *pkt)
00193 {
00194 BMVDecContext * const c = avctx->priv_data;
00195 int type, scr_off;
00196 int i;
00197 uint8_t *srcptr, *outptr;
00198
00199 c->stream = pkt->data;
00200 type = bytestream_get_byte(&c->stream);
00201 if (type & BMV_AUDIO) {
00202 int blobs = bytestream_get_byte(&c->stream);
00203 if (pkt->size < blobs * 65 + 2) {
00204 av_log(avctx, AV_LOG_ERROR, "Audio data doesn't fit in frame\n");
00205 return AVERROR_INVALIDDATA;
00206 }
00207 c->stream += blobs * 65;
00208 }
00209 if (type & BMV_COMMAND) {
00210 int command_size = (type & BMV_PRINT) ? 8 : 10;
00211 if (c->stream - pkt->data + command_size > pkt->size) {
00212 av_log(avctx, AV_LOG_ERROR, "Command data doesn't fit in frame\n");
00213 return AVERROR_INVALIDDATA;
00214 }
00215 c->stream += command_size;
00216 }
00217 if (type & BMV_PALETTE) {
00218 if (c->stream - pkt->data > pkt->size - 768) {
00219 av_log(avctx, AV_LOG_ERROR, "Palette data doesn't fit in frame\n");
00220 return AVERROR_INVALIDDATA;
00221 }
00222 for (i = 0; i < 256; i++)
00223 c->pal[i] = bytestream_get_be24(&c->stream);
00224 }
00225 if (type & BMV_SCROLL) {
00226 if (c->stream - pkt->data > pkt->size - 2) {
00227 av_log(avctx, AV_LOG_ERROR, "Screen offset data doesn't fit in frame\n");
00228 return AVERROR_INVALIDDATA;
00229 }
00230 scr_off = (int16_t)bytestream_get_le16(&c->stream);
00231 } else if ((type & BMV_INTRA) == BMV_INTRA) {
00232 scr_off = -640;
00233 } else {
00234 scr_off = 0;
00235 }
00236
00237 if (decode_bmv_frame(c->stream, pkt->size - (c->stream - pkt->data), c->frame, scr_off)) {
00238 av_log(avctx, AV_LOG_ERROR, "Error decoding frame data\n");
00239 return AVERROR_INVALIDDATA;
00240 }
00241
00242 memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
00243 c->pic.palette_has_changed = type & BMV_PALETTE;
00244
00245 outptr = c->pic.data[0];
00246 srcptr = c->frame;
00247
00248 for (i = 0; i < avctx->height; i++) {
00249 memcpy(outptr, srcptr, avctx->width);
00250 srcptr += avctx->width;
00251 outptr += c->pic.linesize[0];
00252 }
00253
00254 *data_size = sizeof(AVFrame);
00255 *(AVFrame*)data = c->pic;
00256
00257
00258 return pkt->size;
00259 }
00260
00261 static av_cold int decode_init(AVCodecContext *avctx)
00262 {
00263 BMVDecContext * const c = avctx->priv_data;
00264
00265 c->avctx = avctx;
00266 avctx->pix_fmt = PIX_FMT_PAL8;
00267
00268 c->pic.reference = 1;
00269 if (ff_get_buffer(avctx, &c->pic) < 0) {
00270 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00271 return -1;
00272 }
00273
00274 c->frame = c->frame_base + 640;
00275
00276 return 0;
00277 }
00278
00279 static av_cold int decode_end(AVCodecContext *avctx)
00280 {
00281 BMVDecContext *c = avctx->priv_data;
00282
00283 if (c->pic.data[0])
00284 avctx->release_buffer(avctx, &c->pic);
00285
00286 return 0;
00287 }
00288
00289 typedef struct BMVAudioDecContext {
00290 AVFrame frame;
00291 } BMVAudioDecContext;
00292
00293 static const int bmv_aud_mults[16] = {
00294 16512, 8256, 4128, 2064, 1032, 516, 258, 192, 129, 88, 64, 56, 48, 40, 36, 32
00295 };
00296
00297 static av_cold int bmv_aud_decode_init(AVCodecContext *avctx)
00298 {
00299 BMVAudioDecContext *c = avctx->priv_data;
00300
00301 if (avctx->channels != 2) {
00302 av_log(avctx, AV_LOG_INFO, "invalid number of channels\n");
00303 return AVERROR(EINVAL);
00304 }
00305
00306 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
00307
00308 avcodec_get_frame_defaults(&c->frame);
00309 avctx->coded_frame = &c->frame;
00310
00311 return 0;
00312 }
00313
00314 static int bmv_aud_decode_frame(AVCodecContext *avctx, void *data,
00315 int *got_frame_ptr, AVPacket *avpkt)
00316 {
00317 BMVAudioDecContext *c = avctx->priv_data;
00318 const uint8_t *buf = avpkt->data;
00319 int buf_size = avpkt->size;
00320 int blocks = 0, total_blocks, i;
00321 int ret;
00322 int16_t *output_samples;
00323 int scale[2];
00324
00325 total_blocks = *buf++;
00326 if (buf_size < total_blocks * 65 + 1) {
00327 av_log(avctx, AV_LOG_ERROR, "expected %d bytes, got %d\n",
00328 total_blocks * 65 + 1, buf_size);
00329 return AVERROR_INVALIDDATA;
00330 }
00331
00332
00333 c->frame.nb_samples = total_blocks * 32;
00334 if ((ret = ff_get_buffer(avctx, &c->frame)) < 0) {
00335 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00336 return ret;
00337 }
00338 output_samples = (int16_t *)c->frame.data[0];
00339
00340 for (blocks = 0; blocks < total_blocks; blocks++) {
00341 uint8_t code = *buf++;
00342 code = (code >> 1) | (code << 7);
00343 scale[0] = bmv_aud_mults[code & 0xF];
00344 scale[1] = bmv_aud_mults[code >> 4];
00345 for (i = 0; i < 32; i++) {
00346 *output_samples++ = av_clip_int16((scale[0] * (int8_t)*buf++) >> 5);
00347 *output_samples++ = av_clip_int16((scale[1] * (int8_t)*buf++) >> 5);
00348 }
00349 }
00350
00351 *got_frame_ptr = 1;
00352 *(AVFrame *)data = c->frame;
00353
00354 return buf_size;
00355 }
00356
00357 AVCodec ff_bmv_video_decoder = {
00358 .name = "bmv_video",
00359 .type = AVMEDIA_TYPE_VIDEO,
00360 .id = CODEC_ID_BMV_VIDEO,
00361 .priv_data_size = sizeof(BMVDecContext),
00362 .init = decode_init,
00363 .close = decode_end,
00364 .decode = decode_frame,
00365 .long_name = NULL_IF_CONFIG_SMALL("Discworld II BMV video"),
00366 };
00367
00368 AVCodec ff_bmv_audio_decoder = {
00369 .name = "bmv_audio",
00370 .type = AVMEDIA_TYPE_AUDIO,
00371 .id = CODEC_ID_BMV_AUDIO,
00372 .priv_data_size = sizeof(BMVAudioDecContext),
00373 .init = bmv_aud_decode_init,
00374 .decode = bmv_aud_decode_frame,
00375 .capabilities = CODEC_CAP_DR1,
00376 .long_name = NULL_IF_CONFIG_SMALL("Discworld II BMV audio"),
00377 };