cmdutil.c中:
int opt_loglevel(void *optctx, const char *opt, const char *arg)
{
const struct { const char *name; int level; } log_levels[] = {
{ "quiet" , AV_LOG_QUIET },
{ "panic" , AV_LOG_PANIC },
{ "fatal" , AV_LOG_FATAL },
{ "error" , AV_LOG_ERROR },
{ "warning", AV_LOG_WARNING },
{ "info" , AV_LOG_INFO },
{ "verbose", AV_LOG_VERBOSE },
{ "debug" , AV_LOG_DEBUG },
{ "trace" , AV_LOG_TRACE },
};
...
}
对应的宏的详细说明:
/**
* @addtogroup lavu_log
*
* @{
*
* @defgroup lavu_log_constants Logging Constants
*
* @{
*/
/**
* Print no output.
*/
#define AV_LOG_QUIET -8
/**
* Something went really wrong and we will crash now.
*/
#define AV_LOG_PANIC 0
/**
* 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.
* However, not all future data is affected.
*/
#define AV_LOG_ERROR 16
/**
* 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
/**
* Standard information.
*/
#define AV_LOG_INFO 32
/**
* Detailed information.
*/
#define AV_LOG_VERBOSE 40
/**
* Stuff which is only useful for libav* developers.
*/
#define AV_LOG_DEBUG 48
/**
* Extremely verbose debugging, useful for libav* development.
*/
#define AV_LOG_TRACE 56
从定义中可以看出来，随着严重程度逐渐下降，一共包含如下级别：
AV_LOG_PANIC，
AV_LOG_FATAL，
AV_LOG_ERROR，
AV_LOG_WARNING，
AV_LOG_INFO，
AV_LOG_VERBOSE，
AV_LOG_DEBUG。
每个级别定义的数值代表了严重程度，数值越小代表越严重。
默认的级别是AV_LOG_INFO。
此外，还有一个级别不输出任何信息，即AV_LOG_QUIET。
当前系统存在着一个“Log级别”。
所有严重程度高于该级别的Log信息都会输出出来。
例如当前的Log级别是AV_LOG_WARNING，则会输出AV_LOG_PANIC，AV_LOG_FATAL，AV_LOG_ERROR，AV_LOG_WARNING级别的信息，而不会输出AV_LOG_INFO级别的信息。
可以通过av_log_get_level()获得当前Log的级别，通过另一个函数av_log_set_level()设置当前的Log级别。
- 命令行中 指定
ffmpeg -loglevel error -i sample.mp4 output.mkv
- 代码中写日志:
av_log(NULL, AV_LOG_ERROR, "Error while filtering: %s\n", errbuf);
...
int64_t seek_timestamp = timestamp;
...
av_log(NULL, AV_LOG_INFO, "seek_timestamp : %"PRId64"\n",seek_timestamp);
...
uint64_t total_packets = 0, total_size = 0;
...
av_log(NULL, AV_LOG_VERBOSE, " Total: %"PRIu64" packets (%"PRIu64" bytes) demuxed\n",
total_packets, total_size);
References:
https://blog.csdn.net/openswc/article/details/54694477
https://blog.csdn.net/leixiaohua1020/article/details/44243155
