Update public FFmpeg header files from r16647 to r18286.

third_party/ffmpeg/include/libavutil/log.h

 /*
  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifndef AVUTIL_LOG_H
 #define AVUTIL_LOG_H
 
 #include <stdarg.h>
 #include "avutil.h"
 
 /**
- * Describes the class of an AVClass context structure, that is an
+ * Describes the class of an AVClass context structure. That is an
  * arbitrary struct of which the first field is a pointer to an
  * AVClass struct (e.g. AVCodecContext, AVFormatContext etc.).
  */
 typedef struct AVCLASS AVClass;
 struct AVCLASS {
     /**
      * The name of the class; usually it is the same name as the
      * context structure type to which the AVClass is associated.
      */
     const char* class_name;
 
     /**
-     * a pointer to a function which returns the name of a context
-     * instance \p ctx associated with the class
+     * A pointer to a function which returns the name of a context
+     * instance \p ctx associated with the class.
      */
     const char* (*item_name)(void* ctx);
 
     /**
      * a pointer to the first option specified in the class if any or NULL
      *
      * @see av_set_default_options()
      */
     const struct AVOption *option;
 };
 
 /* av_log API */
 
-#if LIBAVUTIL_VERSION_INT < (50<<16)
-#define AV_LOG_QUIET -1
-#define AV_LOG_FATAL 0
-#define AV_LOG_ERROR 0
-#define AV_LOG_WARNING 1
-#define AV_LOG_INFO 1
-#define AV_LOG_VERBOSE 1
-#define AV_LOG_DEBUG 2
-#else
 #define AV_LOG_QUIET    -8
 
 /**
- * something went really wrong and we will crash now
+ * Something went really wrong and we will crash now.
  */
 #define AV_LOG_PANIC     0
 
 /**
- * something went wrong and recovery is not possible
- * like no header in a format which depends on it or a combination
- * of parameters which are not allowed
+ * Something went wrong and recovery is not possible.
+ * For example, no header was found for a format which depends
+ * on headers or an illegal combination of parameters is used.
  */
 #define AV_LOG_FATAL     8
 
 /**
- * something went wrong and cannot losslessly be recovered
- * but not all future data is affected
+ * Something went wrong and cannot losslessly be recovered.
+ * However, not all future data is affected.
  */
 #define AV_LOG_ERROR    16
 
 /**
- * something somehow does not look correct / something which may or may not
- * lead to some problems like use of -vstrict -2
+ * Something somehow does not look correct. This may or may not
+ * lead to problems. An example would be the use of '-vstrict -2'.
  */
 #define AV_LOG_WARNING  24
 
 #define AV_LOG_INFO     32
 #define AV_LOG_VERBOSE  40
 
 /**
- * stuff which is only useful for libav* developers
+ * Stuff which is only useful for libav* developers.
  */
 #define AV_LOG_DEBUG    48
-#endif
-
-#if LIBAVUTIL_VERSION_INT < (50<<16)
-extern int av_log_level;
-#endif
 
 /**
- * Send the specified message to the log if the level is less than or equal to
- * the current av_log_level. By default, all logging messages are sent to
+ * Sends the specified message to the log if the level is less than or equal
+ * to the current av_log_level. By default, all logging messages are sent to
  * stderr. This behavior can be altered by setting a different av_vlog callback
  * function.
  *
  * @param avcl A pointer to an arbitrary struct of which the first field is a
  * pointer to an AVClass struct.
  * @param level The importance level of the message, lower values signifying
  * higher importance.
  * @param fmt The format string (printf-compatible) that specifies how
  * subsequent arguments are converted to output.
  * @see av_vlog
  */
 #ifdef __GNUC__
 void av_log(void*, int level, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 3, 4)));
 #else
 void av_log(void*, int level, const char *fmt, ...);
 #endif
 
 void av_vlog(void*, int level, const char *fmt, va_list);
 int av_log_get_level(void);
 void av_log_set_level(int);
 void av_log_set_callback(void (*)(void*, int, const char*, va_list));
 void av_log_default_callback(void* ptr, int level, const char* fmt, va_list vl);
 
 #endif /* AVUTIL_LOG_H */