text: /*
   * Quicktime Animation (RLE) Video Encoder
   * Copyright (C) 2007 Clemens Fruhwirth
   * Copyright (C) 2007 Alexis Ballier
   *
   * This file is based on flashsvenc.c.
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "libavutil/imgutils.h"
  #include "avcodec.h"
  #include "bytestream.h"
  #include "internal.h"
  
  /** Maximum RLE code for bulk copy */
  #define MAX_RLE_BULK   127
  /** Maximum RLE code for repeat */
  #define MAX_RLE_REPEAT 128
  /** Maximum RLE code for skip */
  #define MAX_RLE_SKIP   254
  
  typedef struct QtrleEncContext {
      AVCodecContext *avctx;
      int pixel_size;
      AVFrame *previous_frame;
      unsigned int max_buf_size;
      int logical_width;
      /**
       * This array will contain at ith position the value of the best RLE code
       * if the line started at pixel i
       * There can be 3 values :
       * skip (0)     : skip as much as possible pixels because they are equal to the
       *                previous frame ones
       * repeat (<-1) : repeat that pixel -rle_code times, still as much as
       *                possible
       * copy (>0)    : copy the raw next rle_code pixels */
      signed char *rlecode_table;
      /**
       * This array will contain the length of the best rle encoding of the line
       * starting at ith pixel */
      int *length_table;
      /**
       * Will contain at ith position the number of consecutive pixels equal to the previous
       * frame starting from pixel i */
      uint8_t* skip_table;
  
      /** Encoded frame is a key frame */
      int key_frame;
  } QtrleEncContext;
  
  static av_cold int qtrle_encode_end(AVCodecContext *avctx)
  {
      QtrleEncContext *s = avctx->priv_data;
  
      av_frame_free(&s->previous_frame);
      av_free(s->rlecode_table);
      av_free(s->length_table);
      av_free(s->skip_table);
      return 0;
  }
  
  static av_cold int qtrle_encode_init(AVCodecContext *avctx)
  {
      QtrleEncContext *s = avctx->priv_data;
  
      if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
          return AVERROR(EINVAL);
      }
      s->avctx=avctx;
      s->logical_width=avctx->width;
  
      switch (avctx->pix_fmt) {
      case AV_PIX_FMT_GRAY8:
          if (avctx->width % 4) {
              av_log(avctx, AV_LOG_ERROR, "Width not being a multiple of 4 is not supported\n");
              return AVERROR(EINVAL);
          }
          s->logical_width = avctx->width / 4;
          s->pixel_size = 4;
          break;
      case AV_PIX_FMT_RGB555BE:
          s->pixel_size = 2;
          break;
      case AV_PIX_FMT_RGB24:
          s->pixel_size = 3;
          break;
      case AV_PIX_FMT_ARGB:
          s->pixel_size = 4;
          break;
      default:
          av_log(avctx, AV_LOG_ERROR, "Unsupported colorspace.\n");
          break;
      }
      avctx->bits_per_coded_sample = avctx->pix_fmt == AV_PIX_FMT_GRAY8 ? 40 : s->pixel_size*8;
  
      s->rlecode_table = av_mallocz(s->logical_width);
      s->skip_table    = av_mallocz(s->logical_width);
      s->length_table  = av_mallocz_array(s->logical_width + 1, sizeof(int));
      if (!s->skip_table || !s->length_table || !s->rlecode_table) {
          av_log(avctx, AV_LOG_ERROR, "Error allocating memory.\n");
          return AVERROR(ENOMEM);
      }
      s->previous_frame = av_frame_alloc();
      if (!s->previous_frame) {
          av_log(avctx, AV_LOG_ERROR, "Error allocating picture\n");
          return AVERROR(ENOMEM);
      }
  
      s->max_buf_size = s->logical_width*s->avctx->height*s->pixel_size*2 /* image base material */
                        + 15                                            /* header + footer */
                        + s->avctx->height*2                            /* skip code+rle end */
                        + s->logical_width/MAX_RLE_BULK + 1             /* rle codes */;
  
      return 0;
  }
  
  /**
   * Compute the best RLE sequence for a line
   */
  static void qtrle_encode_line(QtrleEncContext *s, const AVFrame *p, int line, uint8_t **buf)
  {
      int width=s->logical_width;
      int i;
      signed char rlecode;
  
      /* This will be the number of pixels equal to the previous frame one's
       * starting from the ith pixel */
      unsigned int skipcount;
      /* This will be the number of consecutive equal pixels in the current
       * frame, starting from the ith one also */
      unsigned int av_uninit(repeatcount);
  
      /* The cost of the three different possibilities */
      int total_skip_cost;
      int total_repeat_cost;
  
      int base_bulk_cost;
      int lowest_bulk_cost;
      int lowest_bulk_cost_index;
      int sec_lowest_bulk_cost;
      int sec_lowest_bulk_cost_index;
  
      uint8_t *this_line = p->               data[0] + line*p->               linesize[0] +
          (width - 1)*s->pixel_size;
      uint8_t *prev_line = s->previous_frame->data[0] + line * s->previous_frame->linesize[0] +
          (width - 1)*s->pixel_size;
  
      s->length_table[width] = 0;
      skipcount = 0;
  
      /* Initial values */
      lowest_bulk_cost = INT_MAX / 2;
      lowest_bulk_cost_index = width;
      sec_lowest_bulk_cost = INT_MAX / 2;
      sec_lowest_bulk_cost_index = width;
  
      base_bulk_cost = 1 + s->pixel_size;
  
      for (i = width - 1; i >= 0; i--) {
  
          int prev_bulk_cost;
  
          /* If our lowest bulk cost index is too far away, replace it
           * with the next lowest bulk cost */
          if (FFMIN(width, i + MAX_RLE_BULK) < lowest_bulk_cost_index) {
              lowest_bulk_cost = sec_lowest_bulk_cost;
              lowest_bulk_cost_index = sec_lowest_bulk_cost_index;
  
              sec_lowest_bulk_cost = INT_MAX / 2;
              sec_lowest_bulk_cost_index = width;
          }
  
          /* Deal with the first pixel's bulk cost */
          if (!i) {
              base_bulk_cost++;
              lowest_bulk_cost++;
              sec_lowest_bulk_cost++;
          }
  
          /* Look at the bulk cost of the previous loop and see if it is
           * a new lower bulk cost */
          prev_bulk_cost = s->length_table[i + 1] + base_bulk_cost;
          if (prev_bulk_cost <= sec_lowest_bulk_cost) {
              /* If it's lower than the 2nd lowest, then it may be lower
               * than the lowest */
              if (prev_bulk_cost <= lowest_bulk_cost) {
  
                  /* If we have found a new lowest bulk cost,
                   * then the 2nd lowest bulk cost is now farther than the
                   * lowest bulk cost, and will never be used */
                  sec_lowest_bulk_cost = INT_MAX / 2;
  
                  lowest_bulk_cost = prev_bulk_cost;
                  lowest_bulk_cost_index = i + 1;
              } else {
                  /* Then it must be the 2nd lowest bulk cost */
                  sec_lowest_bulk_cost = prev_bulk_cost;
                  sec_lowest_bulk_cost_index = i + 1;
              }
          }
  
          if (!s->key_frame && !memcmp(this_line, prev_line, s->pixel_size))
              skipcount = FFMIN(skipcount + 1, MAX_RLE_SKIP);
          else
              skipcount = 0;
  
          total_skip_cost  = s->length_table[i + skipcount] + 2;
          s->skip_table[i] = skipcount;
  
  
          if (i < width - 1 && !memcmp(this_line, this_line + s->pixel_size, s->pixel_size))
              repeatcount = FFMIN(repeatcount + 1, MAX_RLE_REPEAT);
          else
              repeatcount = 1;
  
          total_repeat_cost = s->length_table[i + repeatcount] + 1 + s->pixel_size;
  
          /* skip code is free for the first pixel, it costs one byte for repeat and bulk copy
           * so let's make it aware */
          if (i == 0) {
              total_skip_cost--;
              total_repeat_cost++;
          }
  
          if (repeatcount > 1 && (skipcount == 0 || total_repeat_cost < total_skip_cost)) {
              /* repeat is the best */
              s->length_table[i]  = total_repeat_cost;
              s->rlecode_table[i] = -repeatcount;
          }
          else if (skipcount > 0) {
              /* skip is the best choice here */
              s->length_table[i]  = total_skip_cost;
              s->rlecode_table[i] = 0;
          }
          else {
              /* We cannot do neither skip nor repeat
               * thus we use the best bulk copy  */
  
              s->length_table[i]  = lowest_bulk_cost;
              s->rlecode_table[i] = lowest_bulk_cost_index - i;
  
          }
  
          /* These bulk costs increase every iteration */
          lowest_bulk_cost += s->pixel_size;
          sec_lowest_bulk_cost += s->pixel_size;
  
          this_line -= s->pixel_size;
          prev_line -= s->pixel_size;
      }
  
      /* Good! Now we have the best sequence for this line, let's output it. */
  
      /* We do a special case for the first pixel so that we avoid testing it in
       * the whole loop */
  
      i=0;
      this_line = p->               data[0] + line*p->linesize[0];
  
      if (s->rlecode_table[0] == 0) {
          bytestream_put_byte(buf, s->skip_table[0] + 1);
          i += s->skip_table[0];
      }
      else bytestream_put_byte(buf, 1);
  
  
      while (i < width) {
          rlecode = s->rlecode_table[i];
          bytestream_put_byte(buf, rlecode);
          if (rlecode == 0) {
              /* Write a skip sequence */
              bytestream_put_byte(buf, s->skip_table[i] + 1);
              i += s->skip_table[i];
          }
          else if (rlecode > 0) {
              /* bulk copy */
              if (s->avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
                  int j;
                  // QT grayscale colorspace has 0=white and 255=black, we will
                  // ignore the palette that is included in the AVFrame because
                  // AV_PIX_FMT_GRAY8 has defined color mapping
                  for (j = 0; j < rlecode*s->pixel_size; ++j)
                      bytestream_put_byte(buf, *(this_line + i*s->pixel_size + j) ^ 0xff);
              } else {
                  bytestream_put_buffer(buf, this_line + i*s->pixel_size, rlecode*s->pixel_size);
              }
              i += rlecode;
          }
          else {
              /* repeat the bits */
              if (s->avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
                  int j;
                  // QT grayscale colorspace has 0=white and 255=black, ...
                  for (j = 0; j < s->pixel_size; ++j)
                      bytestream_put_byte(buf, *(this_line + i*s->pixel_size + j) ^ 0xff);
              } else {
                  bytestream_put_buffer(buf, this_line + i*s->pixel_size, s->pixel_size);
              }
              i -= rlecode;
          }
      }
      bytestream_put_byte(buf, -1); // end RLE line
  }
  
  /** Encode frame including header */
  static int encode_frame(QtrleEncContext *s, const AVFrame *p, uint8_t *buf)
  {
      int i;
      int start_line = 0;
      int end_line = s->avctx->height;
      uint8_t *orig_buf = buf;
  
      if (!s->key_frame) {
          unsigned line_size = s->logical_width * s->pixel_size;
          for (start_line = 0; start_line < s->avctx->height; start_line++)
              if (memcmp(p->data[0] + start_line*p->linesize[0],
                         s->previous_frame->data[0] + start_line * s->previous_frame->linesize[0],
                         line_size))
                  break;
  
          for (end_line=s->avctx->height; end_line > start_line; end_line--)
              if (memcmp(p->data[0] + (end_line - 1)*p->linesize[0],
                         s->previous_frame->data[0] + (end_line - 1) * s->previous_frame->linesize[0],
                         line_size))
                  break;
      }
  
      bytestream_put_be32(&buf, 0);                         // CHUNK SIZE, patched later
  
      if ((start_line == 0 && end_line == s->avctx->height) || start_line == s->avctx->height)
          bytestream_put_be16(&buf, 0);                     // header
      else {
          bytestream_put_be16(&buf, 8);                     // header
          bytestream_put_be16(&buf, start_line);            // starting line
          bytestream_put_be16(&buf, 0);                     // unknown
          bytestream_put_be16(&buf, end_line - start_line); // lines to update
          bytestream_put_be16(&buf, 0);                     // unknown
      }
      for (i = start_line; i < end_line; i++)
          qtrle_encode_line(s, p, i, &buf);
  
      bytestream_put_byte(&buf, 0);                         // zero skip code = frame finished
      AV_WB32(orig_buf, buf - orig_buf);                    // patch the chunk size
      return buf - orig_buf;
  }
  
  static int qtrle_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                                const AVFrame *pict, int *got_packet)
  {
      QtrleEncContext * const s = avctx->priv_data;
      int ret;
  
      if ((ret = ff_alloc_packet2(avctx, pkt, s->max_buf_size, 0)) < 0)
          return ret;
  
      if (avctx->gop_size == 0 || (s->avctx->frame_number % avctx->gop_size) == 0) {
          /* I-Frame */
          s->key_frame = 1;
      } else {
          /* P-Frame */
          s->key_frame = 0;
      }
  
      pkt->size = encode_frame(s, pict, pkt->data);
  
      /* save the current frame */
      av_frame_unref(s->previous_frame);
      ret = av_frame_ref(s->previous_frame, pict);
      if (ret < 0) {
          av_log(avctx, AV_LOG_ERROR, "cannot add reference\n");
          return ret;
      }
  
  #if FF_API_CODED_FRAME
  FF_DISABLE_DEPRECATION_WARNINGS
      avctx->coded_frame->key_frame = s->key_frame;
      avctx->coded_frame->pict_type = s->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
  FF_ENABLE_DEPRECATION_WARNINGS
  #endif
  
      if (s->key_frame)
          pkt->flags |= AV_PKT_FLAG_KEY;
      *got_packet = 1;
  
      return 0;
  }
  
  AVCodec ff_qtrle_encoder = {
      .name           = "qtrle",
      .long_name      = NULL_IF_CONFIG_SMALL("QuickTime Animation (RLE) video"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_QTRLE,
      .priv_data_size = sizeof(QtrleEncContext),
      .init           = qtrle_encode_init,
      .encode2        = qtrle_encode_frame,
      .close          = qtrle_encode_end,
      .pix_fmts       = (const enum AVPixelFormat[]){
          AV_PIX_FMT_RGB24, AV_PIX_FMT_RGB555BE, AV_PIX_FMT_ARGB, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
      },
  };
  