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++){

void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic){
    int i;
    InternalBuffer *buf, *last;
    assert(pic->type==FF_BUFFER_TYPE_INTERNAL);
    assert(s->internal_buffer_count);
    buf = NULL;
    for(i=0; i<s->internal_buffer_count; i++){
        buf= &((InternalBuffer*)s->internal_buffer)[i];
        if(buf->data[0] == pic->data[0])
            break;
    }
    assert(i < s->internal_buffer_count);
    s->internal_buffer_count--;
    last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
    FFSWAP(InternalBuffer, *buf, *last);
    for(i=0; i<4; i++){
        pic->data[i]=NULL;
    }
    if(s->debug&FF_DEBUG_BUFFERS)
        av_log(s, AV_LOG_DEBUG, "default_release_buffer called on pic %p, %d buffers used\n", pic, s->internal_buffer_count);
}
['void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic){\n    int i;\n    InternalBuffer *buf, *last;\n    assert(pic->type==FF_BUFFER_TYPE_INTERNAL);\n    assert(s->internal_buffer_count);\n    buf = NULL;\n    for(i=0; i<s->internal_buffer_count; i++){\n        buf= &((InternalBuffer*)s->internal_buffer)[i];\n        if(buf->data[0] == pic->data[0])\n            break;\n    }\n    assert(i < s->internal_buffer_count);\n    s->internal_buffer_count--;\n    last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];\n    FFSWAP(InternalBuffer, *buf, *last);\n    for(i=0; i<4; i++){\n        pic->data[i]=NULL;\n    }\n    if(s->debug&FF_DEBUG_BUFFERS)\n        av_log(s, AV_LOG_DEBUG, "default_release_buffer called on pic %p, %d buffers used\\n", pic, s->internal_buffer_count);\n}']