libavcodec/utils.c:313: error: Null Dereference
  pointer `buf` last assigned on line 303 could be null and is dereferenced at line 313, column 5.

libavcodec/utils.c:296:1: start of procedure avcodec_default_release_buffer()
294. }
295. 
296. void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic){
     ^
297.     int i;
298.     InternalBuffer *buf, *last;

libavcodec/utils.c:300:5: 
298.     InternalBuffer *buf, *last;
299. 
300.     assert(pic->type==FF_BUFFER_TYPE_INTERNAL);
         ^
301.     assert(s->internal_buffer_count);
302. 

libavcodec/utils.c:301:5: 
299. 
300.     assert(pic->type==FF_BUFFER_TYPE_INTERNAL);
301.     assert(s->internal_buffer_count);
         ^
302. 
303.     buf = NULL; /* avoids warning */

libavcodec/utils.c:303:5: 
301.     assert(s->internal_buffer_count);
302. 
303.     buf = NULL; /* avoids warning */
         ^
304.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
305.         buf= &((InternalBuffer*)s->internal_buffer)[i];

libavcodec/utils.c:304:9: 
302. 
303.     buf = NULL; /* avoids warning */
304.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
             ^
305.         buf= &((InternalBuffer*)s->internal_buffer)[i];
306.         if(buf->data[0] == pic->data[0])

libavcodec/utils.c:304:14: Loop condition is false. Leaving loop
302. 
303.     buf = NULL; /* avoids warning */
304.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
                  ^
305.         buf= &((InternalBuffer*)s->internal_buffer)[i];
306.         if(buf->data[0] == pic->data[0])

libavcodec/utils.c:309:5: 
307.             break;
308.     }
309.     assert(i < s->internal_buffer_count);
         ^
310.     s->internal_buffer_count--;
311.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];

libavcodec/utils.c:310:5: 
308.     }
309.     assert(i < s->internal_buffer_count);
310.     s->internal_buffer_count--;
         ^
311.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
312. 

libavcodec/utils.c:311:5: 
309.     assert(i < s->internal_buffer_count);
310.     s->internal_buffer_count--;
311.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
         ^
312. 
313.     FFSWAP(InternalBuffer, *buf, *last);

libavcodec/utils.c:313:5: 
311.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
312. 
313.     FFSWAP(InternalBuffer, *buf, *last);
         ^
314. 
315.     for(i=0; i<4; i++){
