/*
  * Indeo Video Interactive v4 compatible decoder
  * Copyright (c) 2009-2011 Maxim Poliakovski
  *

  * 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
  * Indeo Video Interactive version 4 decoder
  *
  * Indeo 4 data is usually transported within .avi or .mov files.
  * Known FOURCCs: 'IV41'
  */
 
 #define BITSTREAM_READER_LE
 #include "avcodec.h"
 #include "get_bits.h"
 #include "ivi_dsp.h"
 #include "ivi_common.h"
 #include "indeo4data.h"
 
 /**
  *  Indeo 4 frame types.
  */
 enum {
     FRAMETYPE_INTRA       = 0,

     FRAMETYPE_INTRA1      = 1,  ///< intra frame with slightly different bitstream coding

     FRAMETYPE_INTER       = 2,  ///< non-droppable P-frame
     FRAMETYPE_BIDIR       = 3,  ///< bidirectional frame
     FRAMETYPE_INTER_NOREF = 4,  ///< droppable P-frame
     FRAMETYPE_NULL_FIRST  = 5,  ///< empty frame with no data
     FRAMETYPE_NULL_LAST   = 6   ///< empty frame with no data
 };
 
 #define IVI4_PIC_SIZE_ESC   7
 
 

 static const struct {

     InvTransformPtr *inv_trans;
     DCTransformPtr  *dc_trans;
     int             is_2d_trans;
 } transforms[18] = {
     { ff_ivi_inverse_haar_8x8,  ff_ivi_dc_haar_2d,       1 },

     { ff_ivi_row_haar8,         ff_ivi_dc_haar_2d,       0 },
     { ff_ivi_col_haar8,         ff_ivi_dc_haar_2d,       0 },

     { ff_ivi_put_pixels_8x8,    ff_ivi_put_dc_pixel_8x8, 1 },
     { ff_ivi_inverse_slant_8x8, ff_ivi_dc_slant_2d,      1 },
     { ff_ivi_row_slant8,        ff_ivi_dc_row_slant,     1 },
     { ff_ivi_col_slant8,        ff_ivi_dc_col_slant,     1 },
     { NULL, NULL, 0 }, /* inverse DCT 8x8 */
     { NULL, NULL, 0 }, /* inverse DCT 8x1 */
     { NULL, NULL, 0 }, /* inverse DCT 1x8 */

     { ff_ivi_inverse_haar_4x4,  ff_ivi_dc_haar_2d,       1 },

     { ff_ivi_inverse_slant_4x4, ff_ivi_dc_slant_2d,      1 },
     { NULL, NULL, 0 }, /* no transform 4x4 */

     { ff_ivi_row_haar4,         ff_ivi_dc_haar_2d,       0 },
     { ff_ivi_col_haar4,         ff_ivi_dc_haar_2d,       0 },
     { ff_ivi_row_slant4,        ff_ivi_dc_row_slant,     0 },
     { ff_ivi_col_slant4,        ff_ivi_dc_col_slant,     0 },

     { NULL, NULL, 0 }, /* inverse DCT 4x4 */
 };
 
 /**
  *  Decode subdivision of a plane.
  *  This is a simplified version that checks for two supported subdivisions:
  *  - 1 wavelet band  per plane, size factor 1:1, code pattern: 3
  *  - 4 wavelet bands per plane, size factor 1:4, code pattern: 2,3,3,3,3
  *  Anything else is either unsupported or corrupt.
  *
  *  @param[in,out] gb    the GetBit context
  *  @return        number of wavelet bands or 0 on error
  */
 static int decode_plane_subdivision(GetBitContext *gb)
 {
     int i;
 
     switch (get_bits(gb, 2)) {
     case 3:
         return 1;
     case 2:
         for (i = 0; i < 4; i++)
             if (get_bits(gb, 2) != 3)
                 return 0;
         return 4;
     default:
         return 0;
     }
 }
 
 static inline int scale_tile_size(int def_size, int size_factor)
 {

     return size_factor == 15 ? def_size : (size_factor + 1) << 5;

 }
 
 /**
  *  Decode Indeo 4 picture header.
  *
  *  @param[in,out] ctx       pointer to the decoder context
  *  @param[in]     avctx     pointer to the AVCodecContext
  *  @return        result code: 0 = OK, negative number = error
  */

 static int decode_pic_hdr(IVI45DecContext *ctx, AVCodecContext *avctx)

 {

     int             pic_size_indx, i, p;

     IVIPicConfig    pic_conf;
 
     if (get_bits(&ctx->gb, 18) != 0x3FFF8) {
         av_log(avctx, AV_LOG_ERROR, "Invalid picture start code!\n");
         return AVERROR_INVALIDDATA;
     }
 
     ctx->prev_frame_type = ctx->frame_type;
     ctx->frame_type      = get_bits(&ctx->gb, 3);
     if (ctx->frame_type == 7) {
         av_log(avctx, AV_LOG_ERROR, "Invalid frame type: %d\n", ctx->frame_type);
         return AVERROR_INVALIDDATA;
     }
 
 #if IVI4_STREAM_ANALYSER

     if (ctx->frame_type == FRAMETYPE_BIDIR)

         ctx->has_b_frames = 1;
 #endif
 
     ctx->transp_status = get_bits1(&ctx->gb);
 #if IVI4_STREAM_ANALYSER
     if (ctx->transp_status) {
         ctx->has_transp = 1;
     }
 #endif
 
     /* unknown bit: Mac decoder ignores this bit, XANIM returns error */
     if (get_bits1(&ctx->gb)) {
         av_log(avctx, AV_LOG_ERROR, "Sync bit is set!\n");
         return AVERROR_INVALIDDATA;
     }
 
     ctx->data_size = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 24) : 0;
 
     /* null frames don't contain anything else so we just return */
     if (ctx->frame_type >= FRAMETYPE_NULL_FIRST) {
         av_dlog(avctx, "Null frame encountered!\n");
         return 0;
     }
 
     /* Check key lock status. If enabled - ignore lock word.         */
     /* Usually we have to prompt the user for the password, but      */
     /* we don't do that because Indeo 4 videos can be decoded anyway */
     if (get_bits1(&ctx->gb)) {
         skip_bits_long(&ctx->gb, 32);
         av_dlog(avctx, "Password-protected clip!\n");
     }
 
     pic_size_indx = get_bits(&ctx->gb, 3);
     if (pic_size_indx == IVI4_PIC_SIZE_ESC) {
         pic_conf.pic_height = get_bits(&ctx->gb, 16);
         pic_conf.pic_width  = get_bits(&ctx->gb, 16);
     } else {
         pic_conf.pic_height = ivi4_common_pic_sizes[pic_size_indx * 2 + 1];
         pic_conf.pic_width  = ivi4_common_pic_sizes[pic_size_indx * 2    ];
     }
 
     /* Decode tile dimensions. */
     if (get_bits1(&ctx->gb)) {
         pic_conf.tile_height = scale_tile_size(pic_conf.pic_height, get_bits(&ctx->gb, 4));
         pic_conf.tile_width  = scale_tile_size(pic_conf.pic_width,  get_bits(&ctx->gb, 4));
 #if IVI4_STREAM_ANALYSER
         ctx->uses_tiling = 1;
 #endif
     } else {
         pic_conf.tile_height = pic_conf.pic_height;
         pic_conf.tile_width  = pic_conf.pic_width;
     }
 
     /* Decode chroma subsampling. We support only 4:4 aka YVU9. */
     if (get_bits(&ctx->gb, 2)) {
         av_log(avctx, AV_LOG_ERROR, "Only YVU9 picture format is supported!\n");
         return AVERROR_INVALIDDATA;
     }
     pic_conf.chroma_height = (pic_conf.pic_height + 3) >> 2;
     pic_conf.chroma_width  = (pic_conf.pic_width  + 3) >> 2;
 
     /* decode subdivision of the planes */
     pic_conf.luma_bands = decode_plane_subdivision(&ctx->gb);

     pic_conf.chroma_bands = 0;

     if (pic_conf.luma_bands)
         pic_conf.chroma_bands = decode_plane_subdivision(&ctx->gb);
     ctx->is_scalable = pic_conf.luma_bands != 1 || pic_conf.chroma_bands != 1;
     if (ctx->is_scalable && (pic_conf.luma_bands != 4 || pic_conf.chroma_bands != 1)) {
         av_log(avctx, AV_LOG_ERROR, "Scalability: unsupported subdivision! Luma bands: %d, chroma bands: %d\n",
                pic_conf.luma_bands, pic_conf.chroma_bands);
         return AVERROR_INVALIDDATA;
     }
 
     /* check if picture layout was changed and reallocate buffers */
     if (ivi_pic_config_cmp(&pic_conf, &ctx->pic_conf)) {
         if (ff_ivi_init_planes(ctx->planes, &pic_conf)) {
             av_log(avctx, AV_LOG_ERROR, "Couldn't reallocate color planes!\n");

             ctx->pic_conf.luma_bands = 0;

             return AVERROR(ENOMEM);
         }
 
         ctx->pic_conf = pic_conf;
 
         /* set default macroblock/block dimensions */
         for (p = 0; p <= 2; p++) {
             for (i = 0; i < (!p ? pic_conf.luma_bands : pic_conf.chroma_bands); i++) {
                 ctx->planes[p].bands[i].mb_size  = !p ? (!ctx->is_scalable ? 16 : 8) : 4;
                 ctx->planes[p].bands[i].blk_size = !p ? 8 : 4;
             }
         }
 
         if (ff_ivi_init_tiles(ctx->planes, ctx->pic_conf.tile_width,
                               ctx->pic_conf.tile_height)) {
             av_log(avctx, AV_LOG_ERROR,
                    "Couldn't reallocate internal structures!\n");
             return AVERROR(ENOMEM);
         }
     }
 
     ctx->frame_num = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 20) : 0;
 
     /* skip decTimeEst field if present */
     if (get_bits1(&ctx->gb))
         skip_bits(&ctx->gb, 8);
 
     /* decode macroblock and block huffman codebooks */
     if (ff_ivi_dec_huff_desc(&ctx->gb, get_bits1(&ctx->gb), IVI_MB_HUFF,  &ctx->mb_vlc,  avctx) ||
         ff_ivi_dec_huff_desc(&ctx->gb, get_bits1(&ctx->gb), IVI_BLK_HUFF, &ctx->blk_vlc, avctx))
         return AVERROR_INVALIDDATA;
 
     ctx->rvmap_sel = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 3) : 8;
 
     ctx->in_imf = get_bits1(&ctx->gb);
     ctx->in_q   = get_bits1(&ctx->gb);
 
     ctx->pic_glob_quant = get_bits(&ctx->gb, 5);
 
     /* TODO: ignore this parameter if unused */
     ctx->unknown1 = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 3) : 0;
 
     ctx->checksum = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 16) : 0;
 
     /* skip picture header extension if any */
     while (get_bits1(&ctx->gb)) {
         av_dlog(avctx, "Pic hdr extension encountered!\n");

         skip_bits(&ctx->gb, 8);

     }
 
     if (get_bits1(&ctx->gb)) {
         av_log(avctx, AV_LOG_ERROR, "Bad blocks bits encountered!\n");
     }
 
     align_get_bits(&ctx->gb);
 
     return 0;
 }
 
 
 /**
  *  Decode Indeo 4 band header.
  *
  *  @param[in,out] ctx       pointer to the decoder context
  *  @param[in,out] band      pointer to the band descriptor
  *  @param[in]     avctx     pointer to the AVCodecContext
  *  @return        result code: 0 = OK, negative number = error
  */

 static int decode_band_hdr(IVI45DecContext *ctx, IVIBandDesc *band,

                            AVCodecContext *avctx)
 {

     int plane, band_num, indx, transform_id, scan_indx;

     int i;

     int quant_mat;

 
     plane    = get_bits(&ctx->gb, 2);
     band_num = get_bits(&ctx->gb, 4);
     if (band->plane != plane || band->band_num != band_num) {
         av_log(avctx, AV_LOG_ERROR, "Invalid band header sequence!\n");
         return AVERROR_INVALIDDATA;
     }
 
     band->is_empty = get_bits1(&ctx->gb);
     if (!band->is_empty) {

         int old_blk_size = band->blk_size;

         /* skip header size
          * If header size is not given, header size is 4 bytes. */
         if (get_bits1(&ctx->gb))
             skip_bits(&ctx->gb, 16);

 
         band->is_halfpel = get_bits(&ctx->gb, 2);
         if (band->is_halfpel >= 2) {
             av_log(avctx, AV_LOG_ERROR, "Invalid/unsupported mv resolution: %d!\n",
                    band->is_halfpel);
             return AVERROR_INVALIDDATA;
         }
 #if IVI4_STREAM_ANALYSER
         if (!band->is_halfpel)
             ctx->uses_fullpel = 1;
 #endif
 
         band->checksum_present = get_bits1(&ctx->gb);
         if (band->checksum_present)
             band->checksum = get_bits(&ctx->gb, 16);
 
         indx = get_bits(&ctx->gb, 2);
         if (indx == 3) {
             av_log(avctx, AV_LOG_ERROR, "Invalid block size!\n");
             return AVERROR_INVALIDDATA;
         }
         band->mb_size  = 16 >> indx;
         band->blk_size = 8 >> (indx >> 1);
 
         band->inherit_mv     = get_bits1(&ctx->gb);
         band->inherit_qdelta = get_bits1(&ctx->gb);
 
         band->glob_quant = get_bits(&ctx->gb, 5);
 
         if (!get_bits1(&ctx->gb) || ctx->frame_type == FRAMETYPE_INTRA) {
             transform_id = get_bits(&ctx->gb, 5);

             if (transform_id >= FF_ARRAY_ELEMS(transforms) ||
                 !transforms[transform_id].inv_trans) {

                 avpriv_request_sample(avctx, "Transform %d", transform_id);

                 return AVERROR_PATCHWELCOME;
             }
             if ((transform_id >= 7 && transform_id <= 9) ||
                  transform_id == 17) {

                 avpriv_request_sample(avctx, "DCT transform");

                 return AVERROR_PATCHWELCOME;
             }
 

             if (transform_id < 10 && band->blk_size < 8) {
                 av_log(avctx, AV_LOG_ERROR, "wrong transform size!\n");
                 return AVERROR_INVALIDDATA;
             }

 #if IVI4_STREAM_ANALYSER
             if ((transform_id >= 0 && transform_id <= 2) || transform_id == 10)
                 ctx->uses_haar = 1;
 #endif
 
             band->inv_transform = transforms[transform_id].inv_trans;
             band->dc_transform  = transforms[transform_id].dc_trans;
             band->is_2d_trans   = transforms[transform_id].is_2d_trans;

             if (transform_id < 10)
                 band->transform_size = 8;
             else
                 band->transform_size = 4;
 

             if (band->blk_size != band->transform_size) {
                 av_log(avctx, AV_LOG_ERROR, "transform and block size mismatch (%d != %d)\n", band->transform_size, band->blk_size);

                 return AVERROR_INVALIDDATA;

             }

 
             scan_indx = get_bits(&ctx->gb, 4);
             if (scan_indx == 15) {
                 av_log(avctx, AV_LOG_ERROR, "Custom scan pattern encountered!\n");
                 return AVERROR_INVALIDDATA;
             }

             if (scan_indx > 4 && scan_indx < 10) {

                 if (band->blk_size != 4) {
                     av_log(avctx, AV_LOG_ERROR, "mismatching scan table!\n");

                     return AVERROR_INVALIDDATA;

                 }
             } else if (band->blk_size != 8) {
                 av_log(avctx, AV_LOG_ERROR, "mismatching scan table!\n");

                 return AVERROR_INVALIDDATA;

             }

             band->scan = scan_index_to_tab[scan_indx];

             band->scan_size = band->blk_size;

             quant_mat = get_bits(&ctx->gb, 5);
             if (quant_mat == 31) {
                 av_log(avctx, AV_LOG_ERROR, "Custom quant matrix encountered!\n");
                 return AVERROR_INVALIDDATA;
             }
             if (quant_mat >= FF_ARRAY_ELEMS(quant_index_to_tab)) {
                 avpriv_request_sample(avctx, "Quantization matrix %d",
                                       quant_mat);

                 return AVERROR_INVALIDDATA;
             }

             band->quant_mat = quant_mat;

         } else {
             if (old_blk_size != band->blk_size) {
                 av_log(avctx, AV_LOG_ERROR,
                        "The band block size does not match the configuration "
                        "inherited\n");
                 return AVERROR_INVALIDDATA;
             }

         }

         if (quant_index_to_tab[band->quant_mat] > 4 && band->blk_size == 4) {
             av_log(avctx, AV_LOG_ERROR, "Invalid quant matrix for 4x4 block encountered!\n");
             band->quant_mat = 0;
             return AVERROR_INVALIDDATA;
         }

         if (band->scan_size != band->blk_size) {
             av_log(avctx, AV_LOG_ERROR, "mismatching scan table!\n");
             return AVERROR_INVALIDDATA;
         }

         if (band->transform_size == 8 && band->blk_size < 8) {
             av_log(avctx, AV_LOG_ERROR, "mismatching transform_size!\n");
             return AVERROR_INVALIDDATA;
         }

         /* decode block huffman codebook */

         if (!get_bits1(&ctx->gb))
             band->blk_vlc.tab = ctx->blk_vlc.tab;
         else
             if (ff_ivi_dec_huff_desc(&ctx->gb, 1, IVI_BLK_HUFF,
                                      &band->blk_vlc, avctx))
                 return AVERROR_INVALIDDATA;

 
         /* select appropriate rvmap table for this band */
         band->rvmap_sel = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 3) : 8;
 
         /* decode rvmap probability corrections if any */
         band->num_corr = 0; /* there is no corrections */
         if (get_bits1(&ctx->gb)) {
             band->num_corr = get_bits(&ctx->gb, 8); /* get number of correction pairs */
             if (band->num_corr > 61) {
                 av_log(avctx, AV_LOG_ERROR, "Too many corrections: %d\n",
                        band->num_corr);
                 return AVERROR_INVALIDDATA;
             }
 
             /* read correction pairs */
             for (i = 0; i < band->num_corr * 2; i++)
                 band->corr[i] = get_bits(&ctx->gb, 8);
         }
     }
 
     if (band->blk_size == 8) {
         band->intra_base = &ivi4_quant_8x8_intra[quant_index_to_tab[band->quant_mat]][0];
         band->inter_base = &ivi4_quant_8x8_inter[quant_index_to_tab[band->quant_mat]][0];
     } else {
         band->intra_base = &ivi4_quant_4x4_intra[quant_index_to_tab[band->quant_mat]][0];
         band->inter_base = &ivi4_quant_4x4_inter[quant_index_to_tab[band->quant_mat]][0];
     }
 
     /* Indeo 4 doesn't use scale tables */
     band->intra_scale = NULL;
     band->inter_scale = NULL;
 
     align_get_bits(&ctx->gb);
 

     if (!band->scan) {
         av_log(avctx, AV_LOG_ERROR, "band->scan not set\n");
         return AVERROR_INVALIDDATA;
     }
 

     return 0;
 }
 
 
 /**
  *  Decode information (block type, cbp, quant delta, motion vector)
  *  for all macroblocks in the current tile.
  *
  *  @param[in,out] ctx       pointer to the decoder context
  *  @param[in,out] band      pointer to the band descriptor
  *  @param[in,out] tile      pointer to the tile descriptor
  *  @param[in]     avctx     pointer to the AVCodecContext
  *  @return        result code: 0 = OK, negative number = error
  */

 static int decode_mb_info(IVI45DecContext *ctx, IVIBandDesc *band,

                           IVITile *tile, AVCodecContext *avctx)
 {
     int         x, y, mv_x, mv_y, mv_delta, offs, mb_offset, blks_per_mb,

                 mv_scale, mb_type_bits, s;

     IVIMbInfo   *mb, *ref_mb;
     int         row_offset = band->mb_size * band->pitch;
 
     mb     = tile->mbs;
     ref_mb = tile->ref_mbs;
     offs   = tile->ypos * band->pitch + tile->xpos;
 
     blks_per_mb  = band->mb_size   != band->blk_size  ? 4 : 1;
     mb_type_bits = ctx->frame_type == FRAMETYPE_BIDIR ? 2 : 1;
 
     /* scale factor for motion vectors */
     mv_scale = (ctx->planes[0].bands[0].mb_size >> 3) - (band->mb_size >> 3);
     mv_x = mv_y = 0;
 

     if (((tile->width + band->mb_size-1)/band->mb_size) * ((tile->height + band->mb_size-1)/band->mb_size) != tile->num_MBs) {
         av_log(avctx, AV_LOG_ERROR, "num_MBs mismatch %d %d %d %d\n", tile->width, tile->height, band->mb_size, tile->num_MBs);
         return -1;
     }
 

     for (y = tile->ypos; y < tile->ypos + tile->height; y += band->mb_size) {
         mb_offset = offs;
 
         for (x = tile->xpos; x < tile->xpos + tile->width; x += band->mb_size) {
             mb->xpos     = x;
             mb->ypos     = y;
             mb->buf_offs = mb_offset;
 
             if (get_bits1(&ctx->gb)) {
                 if (ctx->frame_type == FRAMETYPE_INTRA) {
                     av_log(avctx, AV_LOG_ERROR, "Empty macroblock in an INTRA picture!\n");
                     return AVERROR_INVALIDDATA;
                 }
                 mb->type = 1; /* empty macroblocks are always INTER */
                 mb->cbp  = 0; /* all blocks are empty */
 
                 mb->q_delta = 0;
                 if (!band->plane && !band->band_num && ctx->in_q) {
                     mb->q_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,
                                            IVI_VLC_BITS, 1);
                     mb->q_delta = IVI_TOSIGNED(mb->q_delta);
                 }
 
                 mb->mv_x = mb->mv_y = 0; /* no motion vector coded */

                 if (band->inherit_mv && ref_mb) {

                     /* motion vector inheritance */
                     if (mv_scale) {
                         mb->mv_x = ivi_scale_mv(ref_mb->mv_x, mv_scale);
                         mb->mv_y = ivi_scale_mv(ref_mb->mv_y, mv_scale);
                     } else {
                         mb->mv_x = ref_mb->mv_x;
                         mb->mv_y = ref_mb->mv_y;
                     }
                 }
             } else {
                 if (band->inherit_mv) {

                     /* copy mb_type from corresponding reference mb */

                     if (!ref_mb) {
                         av_log(avctx, AV_LOG_ERROR, "ref_mb unavailable\n");

                         return AVERROR_INVALIDDATA;

                     }

                     mb->type = ref_mb->type;

                 } else if (ctx->frame_type == FRAMETYPE_INTRA ||
                            ctx->frame_type == FRAMETYPE_INTRA1) {

                     mb->type = 0; /* mb_type is always INTRA for intra-frames */
                 } else {
                     mb->type = get_bits(&ctx->gb, mb_type_bits);
                 }
 
                 mb->cbp = get_bits(&ctx->gb, blks_per_mb);
 
                 mb->q_delta = 0;
                 if (band->inherit_qdelta) {
                     if (ref_mb) mb->q_delta = ref_mb->q_delta;
                 } else if (mb->cbp || (!band->plane && !band->band_num &&
                            ctx->in_q)) {
                     mb->q_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,
                                            IVI_VLC_BITS, 1);
                     mb->q_delta = IVI_TOSIGNED(mb->q_delta);
                 }
 
                 if (!mb->type) {
                     mb->mv_x = mb->mv_y = 0; /* there is no motion vector in intra-macroblocks */
                 } else {
                     if (band->inherit_mv) {

                         if (ref_mb)
                             /* motion vector inheritance */
                             if (mv_scale) {
                                 mb->mv_x = ivi_scale_mv(ref_mb->mv_x, mv_scale);
                                 mb->mv_y = ivi_scale_mv(ref_mb->mv_y, mv_scale);
                             } else {
                                 mb->mv_x = ref_mb->mv_x;
                                 mb->mv_y = ref_mb->mv_y;
                             }

                     } else {
                         /* decode motion vector deltas */
                         mv_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,
                                             IVI_VLC_BITS, 1);
                         mv_y += IVI_TOSIGNED(mv_delta);
                         mv_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,
                                             IVI_VLC_BITS, 1);
                         mv_x += IVI_TOSIGNED(mv_delta);
                         mb->mv_x = mv_x;
                         mb->mv_y = mv_y;
                     }
                 }
             }
 

             s= band->is_halfpel;
             if (mb->type)

             if ( x +  (mb->mv_x   >>s) +                 (y+               (mb->mv_y   >>s))*band->pitch < 0 ||
                  x + ((mb->mv_x+s)>>s) + band->mb_size - 1
                    + (y+band->mb_size - 1 +((mb->mv_y+s)>>s))*band->pitch > band->bufsize -1) {
                 av_log(avctx, AV_LOG_ERROR, "motion vector %d %d outside reference\n", x*s + mb->mv_x, y*s + mb->mv_y);

                 return AVERROR_INVALIDDATA;
             }
 

             mb++;
             if (ref_mb)
                 ref_mb++;
             mb_offset += band->mb_size;
         }
 
         offs += row_offset;
     }
 
     align_get_bits(&ctx->gb);
 
     return 0;
 }
 
 
 /**
  *  Rearrange decoding and reference buffers.
  *
  *  @param[in,out] ctx       pointer to the decoder context
  */

 static void switch_buffers(IVI45DecContext *ctx)

 {
     switch (ctx->prev_frame_type) {
     case FRAMETYPE_INTRA:

     case FRAMETYPE_INTRA1:

     case FRAMETYPE_INTER:
         ctx->buf_switch ^= 1;
         ctx->dst_buf     = ctx->buf_switch;
         ctx->ref_buf     = ctx->buf_switch ^ 1;
         break;
     case FRAMETYPE_INTER_NOREF:
         break;
     }
 
     switch (ctx->frame_type) {
     case FRAMETYPE_INTRA:

     case FRAMETYPE_INTRA1:

         ctx->buf_switch = 0;
         /* FALLTHROUGH */
     case FRAMETYPE_INTER:
         ctx->dst_buf = ctx->buf_switch;
         ctx->ref_buf = ctx->buf_switch ^ 1;
         break;
     case FRAMETYPE_INTER_NOREF:
     case FRAMETYPE_NULL_FIRST:
     case FRAMETYPE_NULL_LAST:
         break;
     }
 }
 
 

 static int is_nonnull_frame(IVI45DecContext *ctx)

 {

     return ctx->frame_type < FRAMETYPE_NULL_FIRST;

 }
 
 

 static av_cold int decode_init(AVCodecContext *avctx)

 {

     IVI45DecContext *ctx = avctx->priv_data;

     ff_ivi_init_static_vlc();

     /* copy rvmap tables in our context so we can apply changes to them */
     memcpy(ctx->rvmap_tabs, ff_ivi_rvmap_tabs, sizeof(ff_ivi_rvmap_tabs));

     /* Force allocation of the internal buffers */
     /* during picture header decoding.          */
     ctx->pic_conf.pic_width  = 0;
     ctx->pic_conf.pic_height = 0;
 

     avctx->pix_fmt = AV_PIX_FMT_YUV410P;

 
     ctx->decode_pic_hdr   = decode_pic_hdr;
     ctx->decode_band_hdr  = decode_band_hdr;
     ctx->decode_mb_info   = decode_mb_info;
     ctx->switch_buffers   = switch_buffers;
     ctx->is_nonnull_frame = is_nonnull_frame;

 
     return 0;
 }
 
 
 AVCodec ff_indeo4_decoder = {
     .name           = "indeo4",

     .long_name      = NULL_IF_CONFIG_SMALL("Intel Indeo Video Interactive 4"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_INDEO4,

     .priv_data_size = sizeof(IVI45DecContext),

     .init           = decode_init,

     .close          = ff_ivi_decode_close,
     .decode         = ff_ivi_decode_frame,

     .capabilities   = CODEC_CAP_DR1,

 };