text: /*
   * lossless JPEG encoder
   * Copyright (c) 2000, 2001 Fabrice Bellard
   * Copyright (c) 2003 Alex Beregszaszi
   * Copyright (c) 2003-2004 Michael Niedermayer
   *
   * Support for external huffman table, various fixes (AVID workaround),
   * aspecting, new decode_frame mechanism and apple mjpeg-b support
   *                                  by Alex Beregszaszi
   *
   * 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
   */
  
  /**
   * @file
   * lossless JPEG encoder.
   */
  
  #include "libavutil/frame.h"
  #include "libavutil/mem.h"
  #include "libavutil/pixdesc.h"
  
  #include "avcodec.h"
  #include "dsputil.h"
  #include "internal.h"
  #include "mpegvideo.h"
  #include "mjpeg.h"
  #include "mjpegenc.h"
  
  typedef struct LJpegEncContext {
      DSPContext dsp;
      ScanTable scantable;
      uint16_t matrix[64];
  
      int vsample[3];
      int hsample[3];
  
      uint16_t huff_code_dc_luminance[12];
      uint16_t huff_code_dc_chrominance[12];
      uint8_t  huff_size_dc_luminance[12];
      uint8_t  huff_size_dc_chrominance[12];
  
      uint16_t (*scratch)[4];
  } LJpegEncContext;
  
  static int ljpeg_encode_bgr(AVCodecContext *avctx, PutBitContext *pb,
                              const AVFrame *frame)
  {
      LJpegEncContext *s    = avctx->priv_data;
      const int width       = frame->width;
      const int height      = frame->height;
      const int linesize    = frame->linesize[0];
      uint16_t (*buffer)[4] = s->scratch;
      const int predictor   = avctx->prediction_method+1;
      int left[3], top[3], topleft[3];
      int x, y, i;
  
      for (i = 0; i < 3; i++)
          buffer[0][i] = 1 << (9 - 1);
  
      for (y = 0; y < height; y++) {
          const int modified_predictor = y ? predictor : 1;
          uint8_t *ptr = frame->data[0] + (linesize * y);
  
          if (pb->buf_end - pb->buf - (put_bits_count(pb) >> 3) < width * 3 * 4) {
              av_log(avctx, AV_LOG_ERROR, "encoded frame too large\n");
              return -1;
          }
  
          for (i = 0; i < 3; i++)
              top[i]= left[i]= topleft[i]= buffer[0][i];
  
          for (x = 0; x < width; x++) {
              if(avctx->pix_fmt == AV_PIX_FMT_BGR24){
                  buffer[x][1] =  ptr[3 * x + 0] -     ptr[3 * x + 1] + 0x100;
                  buffer[x][2] =  ptr[3 * x + 2] -     ptr[3 * x + 1] + 0x100;
                  buffer[x][0] = (ptr[3 * x + 0] + 2 * ptr[3 * x + 1] + ptr[3 * x + 2]) >> 2;
              }else{
                  buffer[x][1] =  ptr[4 * x + 0] -     ptr[4 * x + 1] + 0x100;
                  buffer[x][2] =  ptr[4 * x + 2] -     ptr[4 * x + 1] + 0x100;
                  buffer[x][0] = (ptr[4 * x + 0] + 2 * ptr[4 * x + 1] + ptr[4 * x + 2]) >> 2;
              }
  
              for (i = 0; i < 3; i++) {
                  int pred, diff;
  
                  PREDICT(pred, topleft[i], top[i], left[i], modified_predictor);
  
                  topleft[i] = top[i];
                  top[i]     = buffer[x+1][i];
  
                  left[i]    = buffer[x][i];
  
                  diff       = ((left[i] - pred + 0x100) & 0x1FF) - 0x100;
  
                  if (i == 0)
                      ff_mjpeg_encode_dc(pb, diff, s->huff_size_dc_luminance, s->huff_code_dc_luminance); //FIXME ugly
                  else
                      ff_mjpeg_encode_dc(pb, diff, s->huff_size_dc_chrominance, s->huff_code_dc_chrominance);
              }
          }
      }
  
      return 0;
  }
  
  static inline void ljpeg_encode_yuv_mb(LJpegEncContext *s, PutBitContext *pb,
                                         const AVFrame *frame, int predictor,
                                         int mb_x, int mb_y)
  {
      int i;
  
      if (mb_x == 0 || mb_y == 0) {
          for (i = 0; i < 3; i++) {
              uint8_t *ptr;
              int x, y, h, v, linesize;
              h = s->hsample[i];
              v = s->vsample[i];
              linesize = frame->linesize[i];
  
              for (y = 0; y < v; y++) {
                  for (x = 0; x < h; x++) {
                      int pred;
  
                      ptr = frame->data[i] + (linesize * (v * mb_y + y)) + (h * mb_x + x); //FIXME optimize this crap
                      if (y == 0 && mb_y == 0) {
                          if (x == 0 && mb_x == 0)
                              pred = 128;
                          else
                              pred = ptr[-1];
                      } else {
                          if (x == 0 && mb_x == 0) {
                              pred = ptr[-linesize];
                          } else {
                              PREDICT(pred, ptr[-linesize - 1], ptr[-linesize],
                                      ptr[-1], predictor);
                          }
                      }
  
                      if (i == 0)
                          ff_mjpeg_encode_dc(pb, *ptr - pred, s->huff_size_dc_luminance, s->huff_code_dc_luminance); //FIXME ugly
                      else
                          ff_mjpeg_encode_dc(pb, *ptr - pred, s->huff_size_dc_chrominance, s->huff_code_dc_chrominance);
                  }
              }
          }
      } else {
          for (i = 0; i < 3; i++) {
              uint8_t *ptr;
              int x, y, h, v, linesize;
              h = s->hsample[i];
              v = s->vsample[i];
              linesize = frame->linesize[i];
  
              for (y = 0; y < v; y++) {
                  for (x = 0; x < h; x++) {
                      int pred;
  
                      ptr = frame->data[i] + (linesize * (v * mb_y + y)) + (h * mb_x + x); //FIXME optimize this crap
                      PREDICT(pred, ptr[-linesize - 1], ptr[-linesize], ptr[-1], predictor);
  
                      if (i == 0)
                          ff_mjpeg_encode_dc(pb, *ptr - pred, s->huff_size_dc_luminance, s->huff_code_dc_luminance); //FIXME ugly
                      else
                          ff_mjpeg_encode_dc(pb, *ptr - pred, s->huff_size_dc_chrominance, s->huff_code_dc_chrominance);
                  }
              }
          }
      }
  }
  
  static int ljpeg_encode_yuv(AVCodecContext *avctx, PutBitContext *pb,
                              const AVFrame *frame)
  {
      const int predictor = avctx->prediction_method + 1;
      LJpegEncContext *s  = avctx->priv_data;
      const int mb_width  = (avctx->width  + s->hsample[0] - 1) / s->hsample[0];
      const int mb_height = (avctx->height + s->vsample[0] - 1) / s->vsample[0];
      int mb_x, mb_y;
  
      for (mb_y = 0; mb_y < mb_height; mb_y++) {
          if (pb->buf_end - pb->buf - (put_bits_count(pb) >> 3) <
              mb_width * 4 * 3 * s->hsample[0] * s->vsample[0]) {
              av_log(avctx, AV_LOG_ERROR, "encoded frame too large\n");
              return -1;
          }
  
          for (mb_x = 0; mb_x < mb_width; mb_x++)
              ljpeg_encode_yuv_mb(s, pb, frame, predictor, mb_x, mb_y);
      }
  
      return 0;
  }
  
  static int ljpeg_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                                const AVFrame *pict, int *got_packet)
  {
      LJpegEncContext *s = avctx->priv_data;
      PutBitContext pb;
      const int width  = avctx->width;
      const int height = avctx->height;
      const int mb_width  = (width  + s->hsample[0] - 1) / s->hsample[0];
      const int mb_height = (height + s->vsample[0] - 1) / s->vsample[0];
      int max_pkt_size = FF_MIN_BUFFER_SIZE;
      int ret, header_bits;
  
      if(    avctx->pix_fmt == AV_PIX_FMT_BGR0
          || avctx->pix_fmt == AV_PIX_FMT_BGRA
          || avctx->pix_fmt == AV_PIX_FMT_BGR24)
          max_pkt_size += width * height * 3 * 4;
      else {
          max_pkt_size += mb_width * mb_height * 3 * 4
                          * s->hsample[0] * s->vsample[0];
      }
  
      if ((ret = ff_alloc_packet2(avctx, pkt, max_pkt_size)) < 0)
          return ret;
  
      init_put_bits(&pb, pkt->data, pkt->size);
  
      ff_mjpeg_encode_picture_header(avctx, &pb, &s->scantable,
                                     s->matrix, s->matrix);
  
      header_bits = put_bits_count(&pb);
  
      if(    avctx->pix_fmt == AV_PIX_FMT_BGR0
          || avctx->pix_fmt == AV_PIX_FMT_BGRA
          || avctx->pix_fmt == AV_PIX_FMT_BGR24)
          ret = ljpeg_encode_bgr(avctx, &pb, pict);
      else
          ret = ljpeg_encode_yuv(avctx, &pb, pict);
      if (ret < 0)
          return ret;
  
      emms_c();
  
      ff_mjpeg_escape_FF(&pb, header_bits >> 3);
      ff_mjpeg_encode_picture_trailer(&pb, header_bits);
  
      flush_put_bits(&pb);
      pkt->size   = put_bits_ptr(&pb) - pb.buf;
      pkt->flags |= AV_PKT_FLAG_KEY;
      *got_packet = 1;
  
      return 0;
  }
  
  static av_cold int ljpeg_encode_close(AVCodecContext *avctx)
  {
      LJpegEncContext *s = avctx->priv_data;
  
      av_frame_free(&avctx->coded_frame);
      av_freep(&s->scratch);
  
      return 0;
  }
  
  static av_cold int ljpeg_encode_init(AVCodecContext *avctx)
  {
      LJpegEncContext *s = avctx->priv_data;
  
      if ((avctx->pix_fmt == AV_PIX_FMT_YUV420P ||
           avctx->pix_fmt == AV_PIX_FMT_YUV422P ||
           avctx->pix_fmt == AV_PIX_FMT_YUV444P) &&
          avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL) {
          av_log(avctx, AV_LOG_ERROR,
                 "Limited range YUV is non-standard, set strict_std_compliance to "
                 "at least unofficial to use it.\n");
          return AVERROR(EINVAL);
      }
  
      avctx->coded_frame = av_frame_alloc();
      if (!avctx->coded_frame)
          return AVERROR(ENOMEM);
  
      avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
      avctx->coded_frame->key_frame = 1;
  
      s->scratch = av_malloc_array(avctx->width + 1, sizeof(*s->scratch));
  
      ff_dsputil_init(&s->dsp, avctx);
      ff_init_scantable(s->dsp.idct_permutation, &s->scantable, ff_zigzag_direct);
  
      ff_mjpeg_init_hvsample(avctx, s->hsample, s->vsample);
  
      ff_mjpeg_build_huffman_codes(s->huff_size_dc_luminance,
                                   s->huff_code_dc_luminance,
                                   avpriv_mjpeg_bits_dc_luminance,
                                   avpriv_mjpeg_val_dc);
      ff_mjpeg_build_huffman_codes(s->huff_size_dc_chrominance,
                                   s->huff_code_dc_chrominance,
                                   avpriv_mjpeg_bits_dc_chrominance,
                                   avpriv_mjpeg_val_dc);
  
      return 0;
  }
  
  AVCodec ff_ljpeg_encoder = {
      .name           = "ljpeg",
      .long_name      = NULL_IF_CONFIG_SMALL("Lossless JPEG"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_LJPEG,
      .priv_data_size = sizeof(LJpegEncContext),
      .init           = ljpeg_encode_init,
      .encode2        = ljpeg_encode_frame,
      .close          = ljpeg_encode_close,
      .pix_fmts       = (const enum AVPixelFormat[]){
          AV_PIX_FMT_BGR24   , AV_PIX_FMT_BGRA    , AV_PIX_FMT_BGR0,
          AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ422P,
          AV_PIX_FMT_YUV420P , AV_PIX_FMT_YUV444P , AV_PIX_FMT_YUV422P,
          AV_PIX_FMT_NONE},
  };
  