text: /*
   * Raw Video Decoder
   * Copyright (c) 2001 Fabrice Bellard
   *
   * 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
   * Raw Video Decoder
   */
  
  #include "avcodec.h"
  #include "bswapdsp.h"
  #include "get_bits.h"
  #include "internal.h"
  #include "raw.h"
  #include "libavutil/avassert.h"
  #include "libavutil/buffer.h"
  #include "libavutil/common.h"
  #include "libavutil/intreadwrite.h"
  #include "libavutil/imgutils.h"
  #include "libavutil/opt.h"
  
  typedef struct RawVideoContext {
      AVClass *av_class;
      AVBufferRef *palette;
      int frame_size;  /* size of the frame in bytes */
      int flip;
      int is_2_4_bpp; // 2 or 4 bpp raw in avi/mov
      int is_yuv2;
      int is_lt_16bpp; // 16bpp pixfmt and bits_per_coded_sample < 16
      int tff;
  
      BswapDSPContext bbdsp;
      void *bitstream_buf;
      unsigned int bitstream_buf_size;
  } RawVideoContext;
  
  static const AVOption options[]={
  	{"top", "top field first", offsetof(RawVideoContext, tff), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, AV_OPT_FLAG_DECODING_PARAM|AV_OPT_FLAG_VIDEO_PARAM},
  	{NULL}
  };
  
  static const AVClass rawdec_class = {
  	.class_name = "rawdec",
      .option     = options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  static av_cold int raw_init_decoder(AVCodecContext *avctx)
  {
      RawVideoContext *context = avctx->priv_data;
      const AVPixFmtDescriptor *desc;
  
      ff_bswapdsp_init(&context->bbdsp);
  
      if (   avctx->codec_tag == MKTAG('r','a','w',' ')
          || avctx->codec_tag == MKTAG('N','O','1','6'))
          avctx->pix_fmt = avpriv_find_pix_fmt(avpriv_pix_fmt_bps_mov,
                                        avctx->bits_per_coded_sample);
      else if (avctx->codec_tag == MKTAG('W', 'R', 'A', 'W'))
          avctx->pix_fmt = avpriv_find_pix_fmt(avpriv_pix_fmt_bps_avi,
                                        avctx->bits_per_coded_sample);
      else if (avctx->codec_tag && (avctx->codec_tag & 0xFFFFFF) != MKTAG('B','I','T', 0))
          avctx->pix_fmt = avpriv_find_pix_fmt(ff_raw_pix_fmt_tags, avctx->codec_tag);
      else if (avctx->pix_fmt == AV_PIX_FMT_NONE && avctx->bits_per_coded_sample)
          avctx->pix_fmt = avpriv_find_pix_fmt(avpriv_pix_fmt_bps_avi,
                                        avctx->bits_per_coded_sample);
  
      desc = av_pix_fmt_desc_get(avctx->pix_fmt);
      if (!desc) {
          av_log(avctx, AV_LOG_ERROR, "Invalid pixel format.\n");
          return AVERROR(EINVAL);
      }
  
      if (desc->flags & (AV_PIX_FMT_FLAG_PAL | AV_PIX_FMT_FLAG_PSEUDOPAL)) {
          context->palette = av_buffer_alloc(AVPALETTE_SIZE);
          if (!context->palette)
              return AVERROR(ENOMEM);
          if (desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL)
              avpriv_set_systematic_pal2((uint32_t*)context->palette->data, avctx->pix_fmt);
          else
              memset(context->palette->data, 0, AVPALETTE_SIZE);
      }
  
      if ((avctx->extradata_size >= 9 &&
           !memcmp(avctx->extradata + avctx->extradata_size - 9, "BottomUp", 9)) ||
          avctx->codec_tag == MKTAG('c','y','u','v') ||
          avctx->codec_tag == MKTAG(3, 0, 0, 0) ||
          avctx->codec_tag == MKTAG('W','R','A','W'))
          context->flip = 1;
  
      if (avctx->codec_tag == AV_RL32("yuv2") &&
          avctx->pix_fmt   == AV_PIX_FMT_YUYV422)
          context->is_yuv2 = 1;
  
      return 0;
  }
  
  static void flip(AVCodecContext *avctx, AVPicture *picture)
  {
      picture->data[0]     += picture->linesize[0] * (avctx->height - 1);
      picture->linesize[0] *= -1;
  }
  
  /*
   * Scale sample to 16-bit resolution
   */
  #define SCALE16(x, bits) (((x) << (16 - (bits))) | ((x) >> (2 * (bits) - 16)))
  
  /**
   * Scale buffer to 16 bits per coded sample resolution
   */
  #define MKSCALE16(name, r16, w16) \
  static void name(AVCodecContext *avctx, uint8_t * dst, const uint8_t *buf, int buf_size, int packed) \
  { \
      int i; \
      if (!packed) { \
          for (i = 0; i + 1 < buf_size; i += 2) \
              w16(dst + i, SCALE16(r16(buf + i), avctx->bits_per_coded_sample)); \
      } else { \
          GetBitContext gb; \
          init_get_bits(&gb, buf, buf_size * 8); \
          for (i = 0; i < avctx->width * avctx->height; i++) { \
              int sample = get_bits(&gb, avctx->bits_per_coded_sample); \
              w16(dst + i*2, SCALE16(sample, avctx->bits_per_coded_sample)); \
          } \
     } \
  }
  
  MKSCALE16(scale16be, AV_RB16, AV_WB16)
  MKSCALE16(scale16le, AV_RL16, AV_WL16)
  
  static int raw_decode(AVCodecContext *avctx, void *data, int *got_frame,
                        AVPacket *avpkt)
  {
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
      RawVideoContext *context       = avctx->priv_data;
      const uint8_t *buf             = avpkt->data;
      int buf_size                   = avpkt->size;
      int linesize_align             = 4;
      int res, len;
      int need_copy;
  
      AVFrame   *frame   = data;
      AVPicture *picture = data;
  
      if ((avctx->bits_per_coded_sample == 4 || avctx->bits_per_coded_sample == 2) &&
          avctx->pix_fmt == AV_PIX_FMT_PAL8 &&
         (!avctx->codec_tag || avctx->codec_tag == MKTAG('r','a','w',' '))) {
          context->is_2_4_bpp = 1;
          context->frame_size = avpicture_get_size(avctx->pix_fmt,
                                                   FFALIGN(avctx->width, 16),
                                                   avctx->height);
      } else {
          context->is_lt_16bpp = av_get_bits_per_pixel(desc) == 16 && avctx->bits_per_coded_sample && avctx->bits_per_coded_sample < 16;
          context->frame_size = avpicture_get_size(avctx->pix_fmt, avctx->width,
                                                   avctx->height);
      }
      need_copy = !avpkt->buf || context->is_2_4_bpp || context->is_yuv2 || context->is_lt_16bpp;
  
      frame->pict_type        = AV_PICTURE_TYPE_I;
      frame->key_frame        = 1;
  
      res = ff_decode_frame_props(avctx, frame);
      if (res < 0)
          return res;
  
      av_frame_set_pkt_pos     (frame, avctx->internal->pkt->pos);
      av_frame_set_pkt_duration(frame, avctx->internal->pkt->duration);
  
      if (context->tff >= 0) {
          frame->interlaced_frame = 1;
          frame->top_field_first  = context->tff;
      }
  
      if ((res = av_image_check_size(avctx->width, avctx->height, 0, avctx)) < 0)
          return res;
  
      if (need_copy)
          frame->buf[0] = av_buffer_alloc(FFMAX(context->frame_size, buf_size));
      else
          frame->buf[0] = av_buffer_ref(avpkt->buf);
      if (!frame->buf[0])
          return AVERROR(ENOMEM);
  
      //2bpp and 4bpp raw in avi and mov (yes this is ugly ...)
      if (context->is_2_4_bpp) {
          int i;
          uint8_t *dst = frame->buf[0]->data;
          buf_size = context->frame_size - AVPALETTE_SIZE;
          if (avctx->bits_per_coded_sample == 4) {
              for (i = 0; 2 * i + 1 < buf_size && i<avpkt->size; i++) {
                  dst[2 * i + 0] = buf[i] >> 4;
                  dst[2 * i + 1] = buf[i] & 15;
              }
              linesize_align = 8;
          } else {
              av_assert0(avctx->bits_per_coded_sample == 2);
              for (i = 0; 4 * i + 3 < buf_size && i<avpkt->size; i++) {
                  dst[4 * i + 0] = buf[i] >> 6;
                  dst[4 * i + 1] = buf[i] >> 4 & 3;
                  dst[4 * i + 2] = buf[i] >> 2 & 3;
                  dst[4 * i + 3] = buf[i]      & 3;
              }
              linesize_align = 16;
          }
          buf = dst;
      } else if (context->is_lt_16bpp) {
          uint8_t *dst = frame->buf[0]->data;
          int packed = (avctx->codec_tag & 0xFFFFFF) == MKTAG('B','I','T', 0);
          int swap   =  avctx->codec_tag >> 24;
  
          if (packed && swap) {
              av_fast_padded_malloc(&context->bitstream_buf, &context->bitstream_buf_size, buf_size);
              if (!context->bitstream_buf)
                  return AVERROR(ENOMEM);
              if (swap == 16)
                  context->bbdsp.bswap16_buf(context->bitstream_buf, (const uint16_t*)buf, buf_size / 2);
              else if (swap == 32)
                  context->bbdsp.bswap_buf(context->bitstream_buf, (const uint32_t*)buf, buf_size / 4);
              else
                  return AVERROR_INVALIDDATA;
              buf = context->bitstream_buf;
          }
  
          if (desc->flags & AV_PIX_FMT_FLAG_BE)
              scale16be(avctx, dst, buf, buf_size, packed);
          else
              scale16le(avctx, dst, buf, buf_size, packed);
  
          buf = dst;
      } else if (need_copy) {
          memcpy(frame->buf[0]->data, buf, buf_size);
          buf = frame->buf[0]->data;
      }
  
      if (avctx->codec_tag == MKTAG('A', 'V', '1', 'x') ||
          avctx->codec_tag == MKTAG('A', 'V', 'u', 'p'))
          buf += buf_size - context->frame_size;
  
      len = context->frame_size - (avctx->pix_fmt==AV_PIX_FMT_PAL8 ? AVPALETTE_SIZE : 0);
      if (buf_size < len && (avctx->codec_tag & 0xFFFFFF) != MKTAG('B','I','T', 0)) {
          av_log(avctx, AV_LOG_ERROR, "Invalid buffer size, packet size %d < expected frame_size %d\n", buf_size, len);
          av_buffer_unref(&frame->buf[0]);
          return AVERROR(EINVAL);
      }
  
      if ((res = avpicture_fill(picture, buf, avctx->pix_fmt,
                                avctx->width, avctx->height)) < 0) {
          av_buffer_unref(&frame->buf[0]);
          return res;
      }
  
      if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
          const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE,
                                                       NULL);
  
          if (pal) {
              av_buffer_unref(&context->palette);
              context->palette = av_buffer_alloc(AVPALETTE_SIZE);
              if (!context->palette) {
                  av_buffer_unref(&frame->buf[0]);
                  return AVERROR(ENOMEM);
              }
              memcpy(context->palette->data, pal, AVPALETTE_SIZE);
              frame->palette_has_changed = 1;
          }
      }
  
      if ((avctx->pix_fmt==AV_PIX_FMT_BGR24    ||
          avctx->pix_fmt==AV_PIX_FMT_GRAY8    ||
          avctx->pix_fmt==AV_PIX_FMT_RGB555LE ||
          avctx->pix_fmt==AV_PIX_FMT_RGB555BE ||
          avctx->pix_fmt==AV_PIX_FMT_RGB565LE ||
          avctx->pix_fmt==AV_PIX_FMT_MONOWHITE ||
          avctx->pix_fmt==AV_PIX_FMT_PAL8) &&
          FFALIGN(frame->linesize[0], linesize_align) * avctx->height <= buf_size)
          frame->linesize[0] = FFALIGN(frame->linesize[0], linesize_align);
  
      if (avctx->pix_fmt == AV_PIX_FMT_NV12 && avctx->codec_tag == MKTAG('N', 'V', '1', '2') &&
          FFALIGN(frame->linesize[0], linesize_align) * avctx->height +
          FFALIGN(frame->linesize[1], linesize_align) * ((avctx->height + 1) / 2) <= buf_size) {
          int la0 = FFALIGN(frame->linesize[0], linesize_align);
          frame->data[1] += (la0 - frame->linesize[0]) * avctx->height;
          frame->linesize[0] = la0;
          frame->linesize[1] = FFALIGN(frame->linesize[1], linesize_align);
      }
  
      if ((avctx->pix_fmt == AV_PIX_FMT_PAL8 && buf_size < context->frame_size) ||
          (desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL)) {
          frame->buf[1]  = av_buffer_ref(context->palette);
          if (!frame->buf[1]) {
              av_buffer_unref(&frame->buf[0]);
              return AVERROR(ENOMEM);
          }
          frame->data[1] = frame->buf[1]->data;
      }
  
      if (avctx->pix_fmt == AV_PIX_FMT_BGR24 &&
          ((frame->linesize[0] + 3) & ~3) * avctx->height <= buf_size)
          frame->linesize[0] = (frame->linesize[0] + 3) & ~3;
  
      if (context->flip)
          flip(avctx, picture);
  
      if (avctx->codec_tag == MKTAG('Y', 'V', '1', '2') ||
          avctx->codec_tag == MKTAG('Y', 'V', '1', '6') ||
          avctx->codec_tag == MKTAG('Y', 'V', '2', '4') ||
          avctx->codec_tag == MKTAG('Y', 'V', 'U', '9'))
          FFSWAP(uint8_t *, picture->data[1], picture->data[2]);
  
      if (avctx->codec_tag == AV_RL32("I420") && (avctx->width+1)*(avctx->height+1) * 3/2 == buf_size) {
          picture->data[1] = picture->data[1] +  (avctx->width+1)*(avctx->height+1) -avctx->width*avctx->height;
          picture->data[2] = picture->data[2] + ((avctx->width+1)*(avctx->height+1) -avctx->width*avctx->height)*5/4;
      }
  
      if (avctx->codec_tag == AV_RL32("yuv2") &&
          avctx->pix_fmt   == AV_PIX_FMT_YUYV422) {
          int x, y;
          uint8_t *line = picture->data[0];
          for (y = 0; y < avctx->height; y++) {
              for (x = 0; x < avctx->width; x++)
                  line[2 * x + 1] ^= 0x80;
              line += picture->linesize[0];
          }
      }
  
      if (avctx->field_order > AV_FIELD_PROGRESSIVE) { /* we have interlaced material flagged in container */
          frame->interlaced_frame = 1;
          if (avctx->field_order == AV_FIELD_TT || avctx->field_order == AV_FIELD_TB)
              frame->top_field_first = 1;
      }
  
      *got_frame = 1;
      return buf_size;
  }
  
  static av_cold int raw_close_decoder(AVCodecContext *avctx)
  {
      RawVideoContext *context = avctx->priv_data;
  
      av_buffer_unref(&context->palette);
      return 0;
  }
  
  AVCodec ff_rawvideo_decoder = {
  	.name           = "rawvideo",
      .long_name      = NULL_IF_CONFIG_SMALL("raw video"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_RAWVIDEO,
      .priv_data_size = sizeof(RawVideoContext),
      .init           = raw_init_decoder,
      .close          = raw_close_decoder,
      .decode         = raw_decode,
      .priv_class     = &rawdec_class,
      .capabilities   = CODEC_CAP_PARAM_CHANGE,
  };
  