text: /*
   * Alias PIX image encoder
   * Copyright (C) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
   *
   * 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/intreadwrite.h"
  
  #include "avcodec.h"
  #include "bytestream.h"
  #include "internal.h"
  
  #define ALIAS_HEADER_SIZE 10
  
  static av_cold int encode_init(AVCodecContext *avctx)
  {
      avctx->coded_frame = av_frame_alloc();
      if (!avctx->coded_frame)
          return AVERROR(ENOMEM);
      return 0;
  }
  
  static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                          const AVFrame *frame, int *got_packet)
  {
      int width, height, bits_pixel, i, j, length, ret;
      uint8_t *in_buf, *buf;
  
      avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
      avctx->coded_frame->key_frame = 1;
  
      width  = avctx->width;
      height = avctx->height;
  
      if (width > 65535 || height > 65535 ||
          width * height >= INT_MAX / 4 - ALIAS_HEADER_SIZE) {
          av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n", width, height);
          return AVERROR_INVALIDDATA;
      }
  
      switch (avctx->pix_fmt) {
      case AV_PIX_FMT_GRAY8:
          bits_pixel = 8;
          break;
      case AV_PIX_FMT_BGR24:
          bits_pixel = 24;
          break;
      default:
          return AVERROR(EINVAL);
      }
  
      length = ALIAS_HEADER_SIZE + 4 * width * height; // max possible
      if ((ret = ff_alloc_packet(pkt, length)) < 0) {
          av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", length);
          return ret;
      }
  
      buf = pkt->data;
  
      /* Encode header. */
      bytestream_put_be16(&buf, width);
      bytestream_put_be16(&buf, height);
      bytestream_put_be32(&buf, 0); /* X, Y offset */
      bytestream_put_be16(&buf, bits_pixel);
  
      for (j = 0; j < height; j++) {
          in_buf = frame->data[0] + frame->linesize[0] * j;
          for (i = 0; i < width; ) {
              int count = 0;
              int pixel;
  
              if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
                  pixel = *in_buf;
                  while (count < 255 && count + i < width && pixel == *in_buf) {
                      count++;
                      in_buf++;
                  }
                  bytestream_put_byte(&buf, count);
                  bytestream_put_byte(&buf, pixel);
              } else { /* AV_PIX_FMT_BGR24 */
                  pixel = AV_RB24(in_buf);
                  while (count < 255 && count + i < width &&
                         pixel == AV_RB24(in_buf)) {
                      count++;
                      in_buf += 3;
                  }
                  bytestream_put_byte(&buf, count);
                  bytestream_put_be24(&buf, pixel);
              }
              i += count;
          }
      }
  
      /* Total length */
      av_shrink_packet(pkt, buf - pkt->data);
      pkt->flags |= AV_PKT_FLAG_KEY;
      *got_packet = 1;
  
      return 0;
  }
  
  static av_cold int encode_close(AVCodecContext *avctx)
  {
      av_frame_free(&avctx->coded_frame);
      return 0;
  }
  
  AVCodec ff_alias_pix_encoder = {
      .name      = "alias_pix",
      .long_name = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
      .type      = AVMEDIA_TYPE_VIDEO,
      .id        = AV_CODEC_ID_ALIAS_PIX,
      .init      = encode_init,
      .encode2   = encode_frame,
      .close     = encode_close,
      .pix_fmts  = (const enum AVPixelFormat[]) {
          AV_PIX_FMT_BGR24, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
      },
  };
  