avcodec/huffyuv: add a field that represents the number of symbols

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/huffyuv.h

@@ -68,6 +68,7 @@ typedef struct HYuvContext {
     int yuy2;                               //use yuy2 instead of 422P
     int bgr32;                              //use bgr32 instead of bgr24
     int bps;
+    int n;                                  // 1<<bps
     int alpha;
     int chroma;
     int yuv;

libavcodec/huffyuvdec.c

@@ -278,6 +278,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
         s->version = 0;
 
     s->bps = 8;
+    s->n = 1<<s->bps;
     s->chroma = 1;
     if (s->version >= 2) {
         int method, interlace;
@@ -294,6 +295,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
                 s->bitstream_bpp = avctx->bits_per_coded_sample & ~7;
         } else {
             s->bps = (avctx->extradata[1] >> 4) + 1;
+            s->n = 1<<s->bps;
             s->chroma_h_shift = avctx->extradata[1] & 3;
             s->chroma_v_shift = (avctx->extradata[1] >> 2) & 3;
             s->yuv   = !!(((uint8_t*)avctx->extradata)[2] & 1);

libavcodec/huffyuvenc.c

@@ -228,6 +228,7 @@ static av_cold int encode_init(AVCodecContext *avctx)
         av_log(avctx, AV_LOG_ERROR, "format not supported\n");
         return AVERROR(EINVAL);
     }
+    s->n = 1<<s->bps;
 
     avctx->bits_per_coded_sample = s->bitstream_bpp;
     s->decorrelate = s->bitstream_bpp >= 24 && !s->yuv && avctx->pix_fmt != AV_PIX_FMT_GBRP;