/*
  * SVQ1 decoder
  * ported to MPlayer by Arpi <arpi@thot.banki.hu>
  * ported to libavcodec by Nick Kurshev <nickols_k@mail.ru>
  *
  * Copyright (C) 2002 the xine project
  * Copyright (C) 2002 the ffmpeg project
  *
  * SVQ1 Encoder (c) 2004 Mike Melanson <melanson@pcisys.net>
  *
  * 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

  * Sorenson Vector Quantizer #1 (SVQ1) video codec.
  * For more information of the SVQ1 algorithm, visit:
  *   http://www.pcisys.net/~melanson/codecs/
  */
 
 #include "avcodec.h"

 #include "get_bits.h"

 #include "h263.h"

 #include "hpeldsp.h"

 #include "internal.h"

 #include "mathops.h"

 #include "svq1.h"
 
 #undef NDEBUG
 #include <assert.h>
 
 static VLC svq1_block_type;
 static VLC svq1_motion_component;
 static VLC svq1_intra_multistage[6];
 static VLC svq1_inter_multistage[6];
 static VLC svq1_intra_mean;
 static VLC svq1_inter_mean;
 
 /* motion vector (prediction) */
 typedef struct svq1_pmv_s {

     int x;
     int y;

 } svq1_pmv;

 typedef struct SVQ1Context {

     HpelDSPContext hdsp;

     GetBitContext gb;

     AVFrame *prev;

     int width;
     int height;
     int frame_code;
     int nonref;         // 1 if the current frame won't be referenced
 } SVQ1Context;
 

 static const uint8_t string_table[256] = {

     0x00, 0xD5, 0x7F, 0xAA, 0xFE, 0x2B, 0x81, 0x54,
     0x29, 0xFC, 0x56, 0x83, 0xD7, 0x02, 0xA8, 0x7D,
     0x52, 0x87, 0x2D, 0xF8, 0xAC, 0x79, 0xD3, 0x06,
     0x7B, 0xAE, 0x04, 0xD1, 0x85, 0x50, 0xFA, 0x2F,
     0xA4, 0x71, 0xDB, 0x0E, 0x5A, 0x8F, 0x25, 0xF0,
     0x8D, 0x58, 0xF2, 0x27, 0x73, 0xA6, 0x0C, 0xD9,
     0xF6, 0x23, 0x89, 0x5C, 0x08, 0xDD, 0x77, 0xA2,
     0xDF, 0x0A, 0xA0, 0x75, 0x21, 0xF4, 0x5E, 0x8B,
     0x9D, 0x48, 0xE2, 0x37, 0x63, 0xB6, 0x1C, 0xC9,
     0xB4, 0x61, 0xCB, 0x1E, 0x4A, 0x9F, 0x35, 0xE0,
     0xCF, 0x1A, 0xB0, 0x65, 0x31, 0xE4, 0x4E, 0x9B,
     0xE6, 0x33, 0x99, 0x4C, 0x18, 0xCD, 0x67, 0xB2,
     0x39, 0xEC, 0x46, 0x93, 0xC7, 0x12, 0xB8, 0x6D,
     0x10, 0xC5, 0x6F, 0xBA, 0xEE, 0x3B, 0x91, 0x44,
     0x6B, 0xBE, 0x14, 0xC1, 0x95, 0x40, 0xEA, 0x3F,
     0x42, 0x97, 0x3D, 0xE8, 0xBC, 0x69, 0xC3, 0x16,
     0xEF, 0x3A, 0x90, 0x45, 0x11, 0xC4, 0x6E, 0xBB,
     0xC6, 0x13, 0xB9, 0x6C, 0x38, 0xED, 0x47, 0x92,
     0xBD, 0x68, 0xC2, 0x17, 0x43, 0x96, 0x3C, 0xE9,
     0x94, 0x41, 0xEB, 0x3E, 0x6A, 0xBF, 0x15, 0xC0,
     0x4B, 0x9E, 0x34, 0xE1, 0xB5, 0x60, 0xCA, 0x1F,
     0x62, 0xB7, 0x1D, 0xC8, 0x9C, 0x49, 0xE3, 0x36,
     0x19, 0xCC, 0x66, 0xB3, 0xE7, 0x32, 0x98, 0x4D,
     0x30, 0xE5, 0x4F, 0x9A, 0xCE, 0x1B, 0xB1, 0x64,
     0x72, 0xA7, 0x0D, 0xD8, 0x8C, 0x59, 0xF3, 0x26,
     0x5B, 0x8E, 0x24, 0xF1, 0xA5, 0x70, 0xDA, 0x0F,
     0x20, 0xF5, 0x5F, 0x8A, 0xDE, 0x0B, 0xA1, 0x74,
     0x09, 0xDC, 0x76, 0xA3, 0xF7, 0x22, 0x88, 0x5D,
     0xD6, 0x03, 0xA9, 0x7C, 0x28, 0xFD, 0x57, 0x82,
     0xFF, 0x2A, 0x80, 0x55, 0x01, 0xD4, 0x7E, 0xAB,
     0x84, 0x51, 0xFB, 0x2E, 0x7A, 0xAF, 0x05, 0xD0,
     0xAD, 0x78, 0xD2, 0x07, 0x53, 0x86, 0x2C, 0xF9

 };
 

 #define SVQ1_PROCESS_VECTOR()                                           \
     for (; level > 0; i++) {                                            \
         /* process next depth */                                        \
         if (i == m) {                                                   \
             m = n;                                                      \
             if (--level == 0)                                           \
                 break;                                                  \
         }                                                               \
         /* divide block if next bit set */                              \

         if (!get_bits1(bitbuf))                                         \

             break;                                                      \
         /* add child nodes */                                           \
         list[n++] = list[i];                                            \

         list[n++] = list[i] + (((level & 1) ? pitch : 1) << ((level >> 1) + 1));\

     }
 

 #define SVQ1_ADD_CODEBOOK()                                             \
     /* add codebook entries to vector */                                \
     for (j = 0; j < stages; j++) {                                      \
         n3  = codebook[entries[j]] ^ 0x80808080;                        \

         n1 += (n3 & 0xFF00FF00) >> 8;                                   \
         n2 +=  n3 & 0x00FF00FF;                                         \

     }                                                                   \
                                                                         \
     /* clip to [0..255] */                                              \
     if (n1 & 0xFF00FF00) {                                              \

         n3  = (n1 >> 15  & 0x00010001 | 0x01000100) - 0x00010001;       \

         n1 += 0x7F007F00;                                               \

         n1 |= (~n1 >> 15 & 0x00010001 | 0x01000100) - 0x00010001;       \
         n1 &= n3 & 0x00FF00FF;                                          \

     }                                                                   \
                                                                         \
     if (n2 & 0xFF00FF00) {                                              \

         n3  = (n2 >> 15  & 0x00010001 | 0x01000100) - 0x00010001;       \

         n2 += 0x7F007F00;                                               \

         n2 |= (~n2 >> 15 & 0x00010001 | 0x01000100) - 0x00010001;       \
         n2 &= n3 & 0x00FF00FF;                                          \

     }
 

 #define SVQ1_CALC_CODEBOOK_ENTRIES(cbook)                               \
     codebook = (const uint32_t *)cbook[level];                          \
     if (stages > 0)                                                     \
         bit_cache = get_bits(bitbuf, 4 * stages);                       \
     /* calculate codebook entries for this vector */                    \
     for (j = 0; j < stages; j++) {                                      \
         entries[j] = (((bit_cache >> (4 * (stages - j - 1))) & 0xF) +   \
                       16 * j) << (level + 1);                           \
     }                                                                   \

     mean -= stages * 128;                                               \

     n4    = (mean << 16) + mean;

 
 static int svq1_decode_block_intra(GetBitContext *bitbuf, uint8_t *pixels,
                                    int pitch)
 {
     uint32_t bit_cache;
     uint8_t *list[63];
     uint32_t *dst;
     const uint32_t *codebook;
     int entries[6];
     int i, j, m, n;
     int mean, stages;
     unsigned x, y, width, height, level;
     uint32_t n1, n2, n3, n4;
 
     /* initialize list for breadth first processing of vectors */
     list[0] = pixels;
 
     /* recursively process vector */
     for (i = 0, m = 1, n = 1, level = 5; i < n; i++) {
         SVQ1_PROCESS_VECTOR();
 
         /* destination address and vector size */
         dst    = (uint32_t *)list[i];
         width  = 1 << ((4 + level) / 2);
         height = 1 << ((3 + level) / 2);
 
         /* get number of stages (-1 skips vector, 0 for mean only) */
         stages = get_vlc2(bitbuf, svq1_intra_multistage[level].table, 3, 3) - 1;
 
         if (stages == -1) {
             for (y = 0; y < height; y++)
                 memset(&dst[y * (pitch / 4)], 0, width);
             continue;   /* skip vector */
         }
 

         if (stages > 0 && level >= 4) {

             av_dlog(NULL,
                     "Error (svq1_decode_block_intra): invalid vector: stages=%i level=%i\n",
                     stages, level);

             return AVERROR_INVALIDDATA;  /* invalid vector */

         }
 
         mean = get_vlc2(bitbuf, svq1_intra_mean.table, 8, 3);
 
         if (stages == 0) {
             for (y = 0; y < height; y++)
                 memset(&dst[y * (pitch / 4)], mean, width);
         } else {
             SVQ1_CALC_CODEBOOK_ENTRIES(ff_svq1_intra_codebooks);

 
             for (y = 0; y < height; y++) {
                 for (x = 0; x < width / 4; x++, codebook++) {
                     n1 = n4;
                     n2 = n4;
                     SVQ1_ADD_CODEBOOK()
                     /* store result */
                     dst[x] = n1 << 8 | n2;
                 }
                 dst += pitch / 4;
             }

         }

     }
 

     return 0;

 }
 

 static int svq1_decode_block_non_intra(GetBitContext *bitbuf, uint8_t *pixels,
                                        int pitch)
 {
     uint32_t bit_cache;
     uint8_t *list[63];
     uint32_t *dst;
     const uint32_t *codebook;
     int entries[6];
     int i, j, m, n;
     int mean, stages;
     int x, y, width, height, level;
     uint32_t n1, n2, n3, n4;
 
     /* initialize list for breadth first processing of vectors */
     list[0] = pixels;
 
     /* recursively process vector */
     for (i = 0, m = 1, n = 1, level = 5; i < n; i++) {
         SVQ1_PROCESS_VECTOR();
 
         /* destination address and vector size */
         dst    = (uint32_t *)list[i];
         width  = 1 << ((4 + level) / 2);
         height = 1 << ((3 + level) / 2);
 
         /* get number of stages (-1 skips vector, 0 for mean only) */
         stages = get_vlc2(bitbuf, svq1_inter_multistage[level].table, 3, 2) - 1;
 
         if (stages == -1)
             continue;           /* skip vector */
 
         if ((stages > 0) && (level >= 4)) {
             av_dlog(NULL,
                     "Error (svq1_decode_block_non_intra): invalid vector: stages=%i level=%i\n",
                     stages, level);

             return AVERROR_INVALIDDATA;  /* invalid vector */

         }

         mean = get_vlc2(bitbuf, svq1_inter_mean.table, 9, 3) - 256;

         SVQ1_CALC_CODEBOOK_ENTRIES(ff_svq1_inter_codebooks);

 
         for (y = 0; y < height; y++) {
             for (x = 0; x < width / 4; x++, codebook++) {
                 n3 = dst[x];
                 /* add mean value to vector */
                 n1 = n4 + ((n3 & 0xFF00FF00) >> 8);
                 n2 = n4 +  (n3 & 0x00FF00FF);
                 SVQ1_ADD_CODEBOOK()
                 /* store result */
                 dst[x] = n1 << 8 | n2;
             }
             dst += pitch / 4;
         }

     }
     return 0;

 }
 

 static int svq1_decode_motion_vector(GetBitContext *bitbuf, svq1_pmv *mv,
                                      svq1_pmv **pmv)
 {
     int diff;
     int i;

     for (i = 0; i < 2; i++) {
         /* get motion code */
         diff = get_vlc2(bitbuf, svq1_motion_component.table, 7, 2);
         if (diff < 0)

             return AVERROR_INVALIDDATA;

         else if (diff) {
             if (get_bits1(bitbuf))
                 diff = -diff;
         }

         /* add median of motion vector predictors and clip result */
         if (i == 1)
             mv->y = sign_extend(diff + mid_pred(pmv[0]->y, pmv[1]->y, pmv[2]->y), 6);
         else
             mv->x = sign_extend(diff + mid_pred(pmv[0]->x, pmv[1]->x, pmv[2]->x), 6);

     }
 

     return 0;

 }
 

 static void svq1_skip_block(uint8_t *current, uint8_t *previous,
                             int pitch, int x, int y)
 {
     uint8_t *src;
     uint8_t *dst;
     int i;

     src = &previous[x + y * pitch];
     dst = current;

     for (i = 0; i < 16; i++) {
         memcpy(dst, src, 16);
         src += pitch;
         dst += pitch;
     }

 }
 

 static int svq1_motion_inter_block(HpelDSPContext *hdsp, GetBitContext *bitbuf,

                                    uint8_t *current, uint8_t *previous,

                                    int pitch, svq1_pmv *motion, int x, int y,
                                    int width, int height)

 {
     uint8_t *src;
     uint8_t *dst;
     svq1_pmv mv;
     svq1_pmv *pmv[3];
     int result;
 
     /* predict and decode motion vector */
     pmv[0] = &motion[0];
     if (y == 0) {
         pmv[1] =
         pmv[2] = pmv[0];
     } else {

         pmv[1] = &motion[x / 8 + 2];
         pmv[2] = &motion[x / 8 + 4];

     }

     result = svq1_decode_motion_vector(bitbuf, &mv, pmv);

     if (result)

         return result;

     motion[0].x         =
     motion[x / 8 + 2].x =
     motion[x / 8 + 3].x = mv.x;
     motion[0].y         =
     motion[x / 8 + 2].y =
     motion[x / 8 + 3].y = mv.y;

     mv.x = av_clip(mv.x, -2 * x, 2 * (width  - x - 16));
     mv.y = av_clip(mv.y, -2 * y, 2 * (height - y - 16));

     src = &previous[(x + (mv.x >> 1)) + (y + (mv.y >> 1)) * pitch];
     dst = current;

     hdsp->put_pixels_tab[0][(mv.y & 1) << 1 | (mv.x & 1)](dst, src, pitch, 16);

     return 0;

 }
 

 static int svq1_motion_inter_4v_block(HpelDSPContext *hdsp, GetBitContext *bitbuf,

                                       uint8_t *current, uint8_t *previous,

                                       int pitch, svq1_pmv *motion, int x, int y,
                                       int width, int height)

 {
     uint8_t *src;
     uint8_t *dst;
     svq1_pmv mv;
     svq1_pmv *pmv[4];
     int i, result;
 
     /* predict and decode motion vector (0) */
     pmv[0] = &motion[0];
     if (y == 0) {
         pmv[1] =
         pmv[2] = pmv[0];
     } else {
         pmv[1] = &motion[(x / 8) + 2];
         pmv[2] = &motion[(x / 8) + 4];
     }

     result = svq1_decode_motion_vector(bitbuf, &mv, pmv);

     if (result)

         return result;

     /* predict and decode motion vector (1) */
     pmv[0] = &mv;
     if (y == 0) {
         pmv[1] =
         pmv[2] = pmv[0];
     } else {
         pmv[1] = &motion[(x / 8) + 3];
     }
     result = svq1_decode_motion_vector(bitbuf, &motion[0], pmv);

     if (result)

         return result;

     /* predict and decode motion vector (2) */
     pmv[1] = &motion[0];
     pmv[2] = &motion[(x / 8) + 1];

     result = svq1_decode_motion_vector(bitbuf, &motion[(x / 8) + 2], pmv);

     if (result)

         return result;

     /* predict and decode motion vector (3) */
     pmv[2] = &motion[(x / 8) + 2];
     pmv[3] = &motion[(x / 8) + 3];

     result = svq1_decode_motion_vector(bitbuf, pmv[3], pmv);

     if (result)

         return result;

     /* form predictions */
     for (i = 0; i < 4; i++) {
         int mvx = pmv[i]->x + (i  & 1) * 16;
         int mvy = pmv[i]->y + (i >> 1) * 16;

         // FIXME: clipping or padding?

         mvx = av_clip(mvx, -2 * x, 2 * (width  - x - 8));
         mvy = av_clip(mvy, -2 * y, 2 * (height - y - 8));

         src = &previous[(x + (mvx >> 1)) + (y + (mvy >> 1)) * pitch];
         dst = current;

         hdsp->put_pixels_tab[1][((mvy & 1) << 1) | (mvx & 1)](dst, src, pitch, 8);

         /* select next block */
         if (i & 1)
             current += 8 * (pitch - 1);
         else
             current += 8;

     }
 

     return 0;

 }
 

 static int svq1_decode_delta_block(AVCodecContext *avctx, HpelDSPContext *hdsp,

                                    GetBitContext *bitbuf,

                                    uint8_t *current, uint8_t *previous,

                                    int pitch, svq1_pmv *motion, int x, int y,
                                    int width, int height)

 {
     uint32_t block_type;
     int result = 0;
 
     /* get block type */
     block_type = get_vlc2(bitbuf, svq1_block_type.table, 2, 2);
 
     /* reset motion vectors */
     if (block_type == SVQ1_BLOCK_SKIP || block_type == SVQ1_BLOCK_INTRA) {

         motion[0].x         =
         motion[0].y         =
         motion[x / 8 + 2].x =
         motion[x / 8 + 2].y =
         motion[x / 8 + 3].x =
         motion[x / 8 + 3].y = 0;

     }
 

     switch (block_type) {
     case SVQ1_BLOCK_SKIP:
         svq1_skip_block(current, previous, pitch, x, y);
         break;

     case SVQ1_BLOCK_INTER:

         result = svq1_motion_inter_block(hdsp, bitbuf, current, previous,

                                          pitch, motion, x, y, width, height);

         if (result != 0) {

             av_dlog(avctx, "Error in svq1_motion_inter_block %i\n", result);

             break;
         }
         result = svq1_decode_block_non_intra(bitbuf, current, pitch);
         break;

     case SVQ1_BLOCK_INTER_4V:

         result = svq1_motion_inter_4v_block(hdsp, bitbuf, current, previous,

                                             pitch, motion, x, y, width, height);

         if (result != 0) {

             av_dlog(avctx, "Error in svq1_motion_inter_4v_block %i\n", result);

             break;
         }
         result = svq1_decode_block_non_intra(bitbuf, current, pitch);
         break;

     case SVQ1_BLOCK_INTRA:
         result = svq1_decode_block_intra(bitbuf, current, pitch);
         break;

     }
 

     return result;

 }
 

 static void svq1_parse_string(GetBitContext *bitbuf, uint8_t *out)
 {
     uint8_t seed;
     int i;

     out[0] = get_bits(bitbuf, 8);
     seed   = string_table[out[0]];

     for (i = 1; i <= out[0]; i++) {
         out[i] = get_bits(bitbuf, 8) ^ seed;
         seed   = string_table[out[i] ^ seed];
     }

 }
 

 static int svq1_decode_frame_header(AVCodecContext *avctx, AVFrame *frame)

 {

     SVQ1Context *s = avctx->priv_data;
     GetBitContext *bitbuf = &s->gb;

     int frame_size_code;

     int width  = s->width;
     int height = s->height;

     skip_bits(bitbuf, 8); /* temporal_reference */

     /* frame type */

     s->nonref = 0;
     switch (get_bits(bitbuf, 2)) {
     case 0:
         frame->pict_type = AV_PICTURE_TYPE_I;
         break;
     case 2:
         s->nonref = 1;
     case 1:
         frame->pict_type = AV_PICTURE_TYPE_P;
         break;
     default:
         av_log(avctx, AV_LOG_ERROR, "Invalid frame type.\n");

         return AVERROR_INVALIDDATA;

     }

     if (frame->pict_type == AV_PICTURE_TYPE_I) {

         /* unknown fields */

         if (s->frame_code == 0x50 || s->frame_code == 0x60) {

             int csum = get_bits(bitbuf, 16);

             csum = ff_svq1_packet_checksum(bitbuf->buffer,
                                            bitbuf->size_in_bits >> 3,
                                            csum);

             av_dlog(avctx, "%s checksum (%02x) for packet data\n",

                     (csum == 0) ? "correct" : "incorrect", csum);
         }

         if ((s->frame_code ^ 0x10) >= 0x50) {

             uint8_t msg[256];

             svq1_parse_string(bitbuf, msg);

             av_log(avctx, AV_LOG_INFO,

                    "embedded message:\n%s\n", (char *)msg);

         }

         skip_bits(bitbuf, 2);
         skip_bits(bitbuf, 2);
         skip_bits1(bitbuf);

         /* load frame size */
         frame_size_code = get_bits(bitbuf, 3);

         if (frame_size_code == 7) {
             /* load width, height (12 bits each) */

             width  = get_bits(bitbuf, 12);
             height = get_bits(bitbuf, 12);

             if (!width || !height)

                 return AVERROR_INVALIDDATA;

         } else {
             /* get width, height from table */

             width  = ff_svq1_frame_size_table[frame_size_code][0];
             height = ff_svq1_frame_size_table[frame_size_code][1];

         }

     }
 

     /* unknown fields */

     if (get_bits1(bitbuf)) {

         skip_bits1(bitbuf);    /* use packet checksum if (1) */
         skip_bits1(bitbuf);    /* component checksums after image data if (1) */

         if (get_bits(bitbuf, 2) != 0)

             return AVERROR_INVALIDDATA;

     }

     if (get_bits1(bitbuf)) {

         skip_bits1(bitbuf);
         skip_bits(bitbuf, 4);
         skip_bits1(bitbuf);
         skip_bits(bitbuf, 2);

         if (skip_1stop_8data_bits(bitbuf) < 0)
             return AVERROR_INVALIDDATA;

     }
 

     s->width  = width;
     s->height = height;

     return 0;

 }
 

 static int svq1_decode_frame(AVCodecContext *avctx, void *data,

                              int *got_frame, AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size       = avpkt->size;

     SVQ1Context     *s = avctx->priv_data;

     AVFrame       *cur = data;

     uint8_t *current;

     int result, i, x, y, width, height;
     svq1_pmv *pmv;

     /* initialize bit buffer */

     init_get_bits8(&s->gb, buf, buf_size);

     /* decode frame header */

     s->frame_code = get_bits(&s->gb, 22);

     if ((s->frame_code & ~0x70) || !(s->frame_code & 0x60))

         return AVERROR_INVALIDDATA;

     /* swap some header bytes (why?) */

     if (s->frame_code != 0x20) {

         uint32_t *src = (uint32_t *)(buf + 4);

         if (buf_size < 36)
             return AVERROR_INVALIDDATA;

         for (i = 0; i < 4; i++)
             src[i] = ((src[i] << 16) | (src[i] >> 16)) ^ src[7 - i];

     }
 

     result = svq1_decode_frame_header(avctx, cur);

     if (result != 0) {

         av_dlog(avctx, "Error in svq1_decode_frame_header %i\n", result);

         return result;

     }

 
     result = ff_set_dimensions(avctx, s->width, s->height);
     if (result < 0)
         return result;

     if ((avctx->skip_frame >= AVDISCARD_NONREF && s->nonref) ||

         (avctx->skip_frame >= AVDISCARD_NONKEY &&

          cur->pict_type != AV_PICTURE_TYPE_I) ||

         avctx->skip_frame >= AVDISCARD_ALL)
         return buf_size;
 

     result = ff_get_buffer(avctx, cur, s->nonref ? 0 : AV_GET_BUFFER_FLAG_REF);

     if (result < 0)

         return result;

     pmv = av_malloc((FFALIGN(s->width, 16) / 8 + 3) * sizeof(*pmv));
     if (!pmv)

         return AVERROR(ENOMEM);

     /* decode y, u and v components */
     for (i = 0; i < 3; i++) {

         int linesize = cur->linesize[i];

         if (i == 0) {
             width    = FFALIGN(s->width,  16);
             height   = FFALIGN(s->height, 16);
         } else {

             if (avctx->flags & CODEC_FLAG_GRAY)

                 break;
             width    = FFALIGN(s->width  / 4, 16);
             height   = FFALIGN(s->height / 4, 16);

         }
 

         current = cur->data[i];

         if (cur->pict_type == AV_PICTURE_TYPE_I) {

             /* keyframe */
             for (y = 0; y < height; y += 16) {
                 for (x = 0; x < width; x += 16) {
                     result = svq1_decode_block_intra(&s->gb, &current[x],
                                                      linesize);

                     if (result) {

                         av_log(avctx, AV_LOG_ERROR,

                                "Error in svq1_decode_block %i (keyframe)\n",
                                result);
                         goto err;
                     }
                 }
                 current += 16 * linesize;
             }
         } else {
             /* delta frame */

             uint8_t *previous = s->prev->data[i];

             if (!previous ||
                 s->prev->width != s->width || s->prev->height != s->height) {

                 av_log(avctx, AV_LOG_ERROR, "Missing reference frame.\n");
                 result = AVERROR_INVALIDDATA;
                 goto err;
             }
 

             memset(pmv, 0, ((width / 8) + 3) * sizeof(svq1_pmv));
 
             for (y = 0; y < height; y += 16) {
                 for (x = 0; x < width; x += 16) {

                     result = svq1_decode_delta_block(avctx, &s->hdsp,

                                                      &s->gb, &current[x],

                                                      previous, linesize,

                                                      pmv, x, y, width, height);

                     if (result != 0) {

                         av_dlog(avctx,

                                 "Error in svq1_decode_delta_block %i\n",
                                 result);
                         goto err;
                     }
                 }
 
                 pmv[0].x     =
                     pmv[0].y = 0;
 
                 current += 16 * linesize;
             }
         }

     }
 

     if (!s->nonref) {
         av_frame_unref(s->prev);
         result = av_frame_ref(s->prev, cur);
         if (result < 0)
             goto err;
     }

     *got_frame = 1;

     result     = buf_size;

 err:

     av_free(pmv);
     return result;

 }
 

 static av_cold int svq1_decode_init(AVCodecContext *avctx)

 {

     SVQ1Context *s = avctx->priv_data;

     int i;

     int offset = 0;

     s->prev = av_frame_alloc();

     if (!s->prev)

         return AVERROR(ENOMEM);

     s->width            = avctx->width  + 3 & ~3;
     s->height           = avctx->height + 3 & ~3;

     avctx->pix_fmt      = AV_PIX_FMT_YUV410P;

     ff_hpeldsp_init(&s->hdsp, avctx->flags);

     INIT_VLC_STATIC(&svq1_block_type, 2, 4,

                     &ff_svq1_block_type_vlc[0][1], 2, 1,
                     &ff_svq1_block_type_vlc[0][0], 2, 1, 6);

     INIT_VLC_STATIC(&svq1_motion_component, 7, 33,

                     &ff_mvtab[0][1], 2, 1,
                     &ff_mvtab[0][0], 2, 1, 176);

 
     for (i = 0; i < 6; i++) {

         static const uint8_t sizes[2][6] = { { 14, 10, 14, 18, 16, 18 },
                                              { 10, 10, 14, 14, 14, 16 } };

         static VLC_TYPE table[168][2];

         svq1_intra_multistage[i].table           = &table[offset];

         svq1_intra_multistage[i].table_allocated = sizes[0][i];

         offset                                  += sizes[0][i];

         init_vlc(&svq1_intra_multistage[i], 3, 8,

                  &ff_svq1_intra_multistage_vlc[i][0][1], 2, 1,
                  &ff_svq1_intra_multistage_vlc[i][0][0], 2, 1,
                  INIT_VLC_USE_NEW_STATIC);
         svq1_inter_multistage[i].table           = &table[offset];

         svq1_inter_multistage[i].table_allocated = sizes[1][i];

         offset                                  += sizes[1][i];

         init_vlc(&svq1_inter_multistage[i], 3, 8,

                  &ff_svq1_inter_multistage_vlc[i][0][1], 2, 1,
                  &ff_svq1_inter_multistage_vlc[i][0][0], 2, 1,
                  INIT_VLC_USE_NEW_STATIC);

     }
 

     INIT_VLC_STATIC(&svq1_intra_mean, 8, 256,

                     &ff_svq1_intra_mean_vlc[0][1], 4, 2,
                     &ff_svq1_intra_mean_vlc[0][0], 4, 2, 632);

     INIT_VLC_STATIC(&svq1_inter_mean, 9, 512,

                     &ff_svq1_inter_mean_vlc[0][1], 4, 2,
                     &ff_svq1_inter_mean_vlc[0][0], 4, 2, 1434);

 
     return 0;
 }
 

 static av_cold int svq1_decode_end(AVCodecContext *avctx)

 {

     SVQ1Context *s = avctx->priv_data;
 

     av_frame_free(&s->prev);

 
     return 0;
 }
 

 static void svq1_flush(AVCodecContext *avctx)
 {
     SVQ1Context *s = avctx->priv_data;
 

     av_frame_unref(s->prev);

 }
 

 AVCodec ff_svq1_decoder = {

     .name           = "svq1",

     .long_name      = NULL_IF_CONFIG_SMALL("Sorenson Vector Quantizer 1 / Sorenson Video 1 / SVQ1"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_SVQ1,

     .priv_data_size = sizeof(SVQ1Context),

     .init           = svq1_decode_init,
     .close          = svq1_decode_end,
     .decode         = svq1_decode_frame,
     .capabilities   = CODEC_CAP_DR1,

     .flush          = svq1_flush,

     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV410P,
                                                      AV_PIX_FMT_NONE },

 };