ffv1: add a minor version field beginning with ffv1.3

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

libavcodec/ffv1.c

@@ -165,6 +165,7 @@ typedef struct FFV1Context{
     uint64_t rc_stat[256][2];
     uint64_t (*rc_stat2[MAX_QUANT_TABLES])[32][2];
     int version;
+    int minor_version;
     int width, height;
     int chroma_h_shift, chroma_v_shift;
     int chroma_planes;
@@ -778,6 +779,8 @@ static int write_extra_header(FFV1Context *f){
     ff_build_rac_states(c, 0.05*(1LL<<32), 256-8);
 
     put_symbol(c, state, f->version, 0);
+    if(f->version > 2)
+        put_symbol(c, state, f->minor_version, 0);
     put_symbol(c, state, f->ac, 0);
     if(f->ac>1){
         for(i=1; i<256; i++){
@@ -1543,6 +1546,8 @@ static int read_extra_header(FFV1Context *f){
     ff_build_rac_states(c, 0.05*(1LL<<32), 256-8);
 
     f->version= get_symbol(c, state, 0);
+    if(f->version > 2)
+        f->minor_version= get_symbol(c, state, 0);
     f->ac= f->avctx->coder_type= get_symbol(c, state, 0);
     if(f->ac>1){
         for(i=1; i<256; i++){