libavcodec/qtrleenc.c

   1 /*
   2  * Quicktime Animation (RLE) Video Encoder
   3  * Copyright (C) 2007 Clemens Fruhwirth
   4  * Copyright (C) 2007 Alexis Ballier
   5  *
   6  * This file is based on flashsvenc.c.
   7  *
   8  * This file is part of Libav.
   9  *
  10  * Libav is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * Libav is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with Libav; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 #include "libavutil/imgutils.h"
  26 #include "avcodec.h"
  27 #include "bytestream.h"
  28 #include "internal.h"
  29
  30 /** Maximum RLE code for bulk copy */
  31 #define MAX_RLE_BULK   127
  32 /** Maximum RLE code for repeat */
  33 #define MAX_RLE_REPEAT 128
  34 /** Maximum RLE code for skip */
  35 #define MAX_RLE_SKIP   254
  36
  37 typedef struct QtrleEncContext {
  38     AVCodecContext *avctx;
  39     int pixel_size;
  40     AVFrame *previous_frame;
  41     unsigned int max_buf_size;
  42     /**
  43      * This array will contain at ith position the value of the best RLE code
  44      * if the line started at pixel i
  45      * There can be 3 values :
  46      * skip (0)     : skip as much as possible pixels because they are equal to the
  47      *                previous frame ones
  48      * repeat (<-1) : repeat that pixel -rle_code times, still as much as
  49      *                possible
  50      * copy (>0)    : copy the raw next rle_code pixels */
  51     signed char *rlecode_table;
  52     /**
  53      * This array will contain the length of the best rle encoding of the line
  54      * starting at ith pixel */
  55     int *length_table;
  56     /**
  57      * Will contain at ith position the number of consecutive pixels equal to the previous
  58      * frame starting from pixel i */
  59     uint8_t* skip_table;
  60
  61     /** Encoded frame is a key frame */
  62     int key_frame;
  63 } QtrleEncContext;
  64
  65 static av_cold int qtrle_encode_end(AVCodecContext *avctx)
  66 {
  67     QtrleEncContext *s = avctx->priv_data;
  68
  69     av_frame_free(&s->previous_frame);
  70     av_free(s->rlecode_table);
  71     av_free(s->length_table);
  72     av_free(s->skip_table);
  73     return 0;
  74 }
  75
  76 static av_cold int qtrle_encode_init(AVCodecContext *avctx)
  77 {
  78     QtrleEncContext *s = avctx->priv_data;
  79
  80     if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
  81         return -1;
  82     }
  83     s->avctx=avctx;
  84
  85     switch (avctx->pix_fmt) {
  86     case AV_PIX_FMT_RGB555BE:
  87         s->pixel_size = 2;
  88         break;
  89     case AV_PIX_FMT_RGB24:
  90         s->pixel_size = 3;
  91         break;
  92     case AV_PIX_FMT_ARGB:
  93         s->pixel_size = 4;
  94         break;
  95     default:
  96         av_log(avctx, AV_LOG_ERROR, "Unsupported colorspace.\n");
  97         break;
  98     }
  99     avctx->bits_per_coded_sample = s->pixel_size*8;
 100
 101     s->rlecode_table = av_mallocz(s->avctx->width);
 102     s->skip_table    = av_mallocz(s->avctx->width);
 103     s->length_table  = av_mallocz((s->avctx->width + 1)*sizeof(int));
 104     if (!s->skip_table || !s->length_table || !s->rlecode_table) {
 105         av_log(avctx, AV_LOG_ERROR, "Error allocating memory.\n");
 106         return -1;
 107     }
 108     s->previous_frame = av_frame_alloc();
 109     if (!s->previous_frame) {
 110         av_log(avctx, AV_LOG_ERROR, "Error allocating picture\n");
 111         return -1;
 112     }
 113
 114     s->max_buf_size = s->avctx->width*s->avctx->height*s->pixel_size*2 /* image base material */
 115                       + 15                                           /* header + footer */
 116                       + s->avctx->height*2                           /* skip code+rle end */
 117                       + s->avctx->width/MAX_RLE_BULK + 1             /* rle codes */;
 118
 119     return 0;
 120 }
 121
 122 /**
 123  * Compute the best RLE sequence for a line
 124  */
 125 static void qtrle_encode_line(QtrleEncContext *s, const AVFrame *p, int line, uint8_t **buf)
 126 {
 127     int width=s->avctx->width;
 128     int i;
 129     signed char rlecode;
 130
 131     /* We will use it to compute the best bulk copy sequence */
 132     unsigned int bulkcount;
 133     /* This will be the number of pixels equal to the previous frame one's
 134      * starting from the ith pixel */
 135     unsigned int skipcount;
 136     /* This will be the number of consecutive equal pixels in the current
 137      * frame, starting from the ith one also */
 138     unsigned int repeatcount;
 139
 140     /* The cost of the three different possibilities */
 141     int total_bulk_cost;
 142     int total_skip_cost;
 143     int total_repeat_cost;
 144
 145     int temp_cost;
 146     int j;
 147
 148     uint8_t *this_line = p->               data[0] + line*p->               linesize[0] +
 149         (width - 1)*s->pixel_size;
 150     uint8_t *prev_line = s->previous_frame->data[0] + line * s->previous_frame->linesize[0] +
 151         (width - 1)*s->pixel_size;
 152
 153     s->length_table[width] = 0;
 154     skipcount = 0;
 155
 156     for (i = width - 1; i >= 0; i--) {
 157
 158         if (!s->key_frame && !memcmp(this_line, prev_line, s->pixel_size))
 159             skipcount = FFMIN(skipcount + 1, MAX_RLE_SKIP);
 160         else
 161             skipcount = 0;
 162
 163         total_skip_cost  = s->length_table[i + skipcount] + 2;
 164         s->skip_table[i] = skipcount;
 165
 166
 167         if (i < width - 1 && !memcmp(this_line, this_line + s->pixel_size, s->pixel_size))
 168             repeatcount = FFMIN(repeatcount + 1, MAX_RLE_REPEAT);
 169         else
 170             repeatcount = 1;
 171
 172         total_repeat_cost = s->length_table[i + repeatcount] + 1 + s->pixel_size;
 173
 174         /* skip code is free for the first pixel, it costs one byte for repeat and bulk copy
 175          * so let's make it aware */
 176         if (i == 0) {
 177             total_skip_cost--;
 178             total_repeat_cost++;
 179         }
 180
 181         if (repeatcount > 1 && (skipcount == 0 || total_repeat_cost < total_skip_cost)) {
 182             /* repeat is the best */
 183             s->length_table[i]  = total_repeat_cost;
 184             s->rlecode_table[i] = -repeatcount;
 185         }
 186         else if (skipcount > 0) {
 187             /* skip is the best choice here */
 188             s->length_table[i]  = total_skip_cost;
 189             s->rlecode_table[i] = 0;
 190         }
 191         else {
 192             /* We cannot do neither skip nor repeat
 193              * thus we search for the best bulk copy to do */
 194
 195             int limit = FFMIN(width - i, MAX_RLE_BULK);
 196
 197             temp_cost = 1 + s->pixel_size + !i;
 198             total_bulk_cost = INT_MAX;
 199
 200             for (j = 1; j <= limit; j++) {
 201                 if (s->length_table[i + j] + temp_cost < total_bulk_cost) {
 202                     /* We have found a better bulk copy ... */
 203                     total_bulk_cost = s->length_table[i + j] + temp_cost;
 204                     bulkcount = j;
 205                 }
 206                 temp_cost += s->pixel_size;
 207             }
 208
 209             s->length_table[i]  = total_bulk_cost;
 210             s->rlecode_table[i] = bulkcount;
 211         }
 212
 213         this_line -= s->pixel_size;
 214         prev_line -= s->pixel_size;
 215     }
 216
 217     /* Good! Now we have the best sequence for this line, let's output it. */
 218
 219     /* We do a special case for the first pixel so that we avoid testing it in
 220      * the whole loop */
 221
 222     i=0;
 223     this_line = p->               data[0] + line*p->linesize[0];
 224
 225     if (s->rlecode_table[0] == 0) {
 226         bytestream_put_byte(buf, s->skip_table[0] + 1);
 227         i += s->skip_table[0];
 228     }
 229     else bytestream_put_byte(buf, 1);
 230
 231
 232     while (i < width) {
 233         rlecode = s->rlecode_table[i];
 234         bytestream_put_byte(buf, rlecode);
 235         if (rlecode == 0) {
 236             /* Write a skip sequence */
 237             bytestream_put_byte(buf, s->skip_table[i] + 1);
 238             i += s->skip_table[i];
 239         }
 240         else if (rlecode > 0) {
 241             /* bulk copy */
 242             bytestream_put_buffer(buf, this_line + i*s->pixel_size, rlecode*s->pixel_size);
 243             i += rlecode;
 244         }
 245         else {
 246             /* repeat the bits */
 247             bytestream_put_buffer(buf, this_line + i*s->pixel_size, s->pixel_size);
 248             i -= rlecode;
 249         }
 250     }
 251     bytestream_put_byte(buf, -1); // end RLE line
 252 }
 253
 254 /** Encode frame including header */
 255 static int encode_frame(QtrleEncContext *s, const AVFrame *p, uint8_t *buf)
 256 {
 257     int i;
 258     int start_line = 0;
 259     int end_line = s->avctx->height;
 260     uint8_t *orig_buf = buf;
 261
 262     if (!s->key_frame) {
 263         unsigned line_size = s->avctx->width * s->pixel_size;
 264         for (start_line = 0; start_line < s->avctx->height; start_line++)
 265             if (memcmp(p->data[0] + start_line*p->linesize[0],
 266                        s->previous_frame->data[0] + start_line * s->previous_frame->linesize[0],
 267                        line_size))
 268                 break;
 269
 270         for (end_line=s->avctx->height; end_line > start_line; end_line--)
 271             if (memcmp(p->data[0] + (end_line - 1)*p->linesize[0],
 272                        s->previous_frame->data[0] + (end_line - 1) * s->previous_frame->linesize[0],
 273                        line_size))
 274                 break;
 275     }
 276
 277     bytestream_put_be32(&buf, 0);                         // CHUNK SIZE, patched later
 278
 279     if ((start_line == 0 && end_line == s->avctx->height) || start_line == s->avctx->height)
 280         bytestream_put_be16(&buf, 0);                     // header
 281     else {
 282         bytestream_put_be16(&buf, 8);                     // header
 283         bytestream_put_be16(&buf, start_line);            // starting line
 284         bytestream_put_be16(&buf, 0);                     // unknown
 285         bytestream_put_be16(&buf, end_line - start_line); // lines to update
 286         bytestream_put_be16(&buf, 0);                     // unknown
 287     }
 288     for (i = start_line; i < end_line; i++)
 289         qtrle_encode_line(s, p, i, &buf);
 290
 291     bytestream_put_byte(&buf, 0);                         // zero skip code = frame finished
 292     AV_WB32(orig_buf, buf - orig_buf);                    // patch the chunk size
 293     return buf - orig_buf;
 294 }
 295
 296 static int qtrle_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
 297                               const AVFrame *pict, int *got_packet)
 298 {
 299     QtrleEncContext * const s = avctx->priv_data;
 300 #if FF_API_CODED_FRAME
 301     enum AVPictureType pict_type;
 302 #endif
 303     int ret;
 304
 305     if ((ret = ff_alloc_packet(pkt, s->max_buf_size)) < 0) {
 306         /* Upper bound check for compressed data */
 307         av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", s->max_buf_size);
 308         return ret;
 309     }
 310
 311     if (avctx->gop_size == 0 || (s->avctx->frame_number % avctx->gop_size) == 0) {
 312         /* I-Frame */
 313 #if FF_API_CODED_FRAME
 314         pict_type = AV_PICTURE_TYPE_I;
 315 #endif
 316         s->key_frame = 1;
 317     } else {
 318         /* P-Frame */
 319 #if FF_API_CODED_FRAME
 320         pict_type = AV_PICTURE_TYPE_P;
 321 #endif
 322         s->key_frame = 0;
 323     }
 324
 325     pkt->size = encode_frame(s, pict, pkt->data);
 326
 327     /* save the current frame */
 328     av_frame_unref(s->previous_frame);
 329     ret = av_frame_ref(s->previous_frame, pict);
 330     if (ret < 0) {
 331         av_log(avctx, AV_LOG_ERROR, "cannot add reference\n");
 332         return ret;
 333     }
 334
 335 #if FF_API_CODED_FRAME
 336 FF_DISABLE_DEPRECATION_WARNINGS
 337     avctx->coded_frame->key_frame = s->key_frame;
 338     avctx->coded_frame->pict_type = pict_type;
 339 FF_ENABLE_DEPRECATION_WARNINGS
 340 #endif
 341
 342     if (s->key_frame)
 343         pkt->flags |= AV_PKT_FLAG_KEY;
 344     *got_packet = 1;
 345
 346     return 0;
 347 }
 348
 349 AVCodec ff_qtrle_encoder = {
 350     .name           = "qtrle",
 351     .long_name      = NULL_IF_CONFIG_SMALL("QuickTime Animation (RLE) video"),
 352     .type           = AVMEDIA_TYPE_VIDEO,
 353     .id             = AV_CODEC_ID_QTRLE,
 354     .priv_data_size = sizeof(QtrleEncContext),
 355     .init           = qtrle_encode_init,
 356     .encode2        = qtrle_encode_frame,
 357     .close          = qtrle_encode_end,
 358     .pix_fmts       = (const enum AVPixelFormat[]){
 359         AV_PIX_FMT_RGB24, AV_PIX_FMT_RGB555BE, AV_PIX_FMT_ARGB, AV_PIX_FMT_NONE
 360     },
 361 };