libavcodec/utils.c:306: error: Null Dereference
  pointer `buf` last assigned on line 296 could be null and is dereferenced at line 306, column 5.

libavcodec/utils.c:289:1: start of procedure avcodec_default_release_buffer()
287. }
288. 
289. void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic){
     ^
290.     int i;
291.     InternalBuffer *buf, *last;

libavcodec/utils.c:293:5: 
291.     InternalBuffer *buf, *last;
292. 
293.     assert(pic->type==FF_BUFFER_TYPE_INTERNAL);
         ^
294.     assert(s->internal_buffer_count);
295. 

libavcodec/utils.c:294:5: 
292. 
293.     assert(pic->type==FF_BUFFER_TYPE_INTERNAL);
294.     assert(s->internal_buffer_count);
         ^
295. 
296.     buf = NULL; /* avoids warning */

libavcodec/utils.c:296:5: 
294.     assert(s->internal_buffer_count);
295. 
296.     buf = NULL; /* avoids warning */
         ^
297.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
298.         buf= &((InternalBuffer*)s->internal_buffer)[i];

libavcodec/utils.c:297:9: 
295. 
296.     buf = NULL; /* avoids warning */
297.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
             ^
298.         buf= &((InternalBuffer*)s->internal_buffer)[i];
299.         if(buf->data[0] == pic->data[0])

libavcodec/utils.c:297:14: Loop condition is false. Leaving loop
295. 
296.     buf = NULL; /* avoids warning */
297.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
                  ^
298.         buf= &((InternalBuffer*)s->internal_buffer)[i];
299.         if(buf->data[0] == pic->data[0])

libavcodec/utils.c:302:5: 
300.             break;
301.     }
302.     assert(i < s->internal_buffer_count);
         ^
303.     s->internal_buffer_count--;
304.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];

libavcodec/utils.c:303:5: 
301.     }
302.     assert(i < s->internal_buffer_count);
303.     s->internal_buffer_count--;
         ^
304.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
305. 

libavcodec/utils.c:304:5: 
302.     assert(i < s->internal_buffer_count);
303.     s->internal_buffer_count--;
304.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
         ^
305. 
306.     FFSWAP(InternalBuffer, *buf, *last);

libavcodec/utils.c:306:5: 
304.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
305. 
306.     FFSWAP(InternalBuffer, *buf, *last);
         ^
307. 
308.     for(i=0; i<4; i++){
