Hello,
I am working with ffmpeg libav* 3.2 libs, downloaded pre-built from Zeranoe
early November, my versions are:
libavutil 55. 34.100 / 55. 34.100
libavcodec 57. 64.100 / 57. 64.100
libavformat 57. 56.100 / 57. 56.100
libavdevice 57. 1.100 / 57. 1.100
libavfilter 6. 65.100 / 6. 65.100
libswscale 4. 2.100 / 4. 2.100
libswresample 2. 3.100 / 2. 3.100
libpostproc 54. 1.100 / 54. 1.100
I’m developing a video playback library, (no audio handling.) I started with
the Dranger tutorials, but have updated everything to the latest APIs from
reading here, and other sources. So far the code is having no problems playing
live USB video, or any video file I can find, but does not play IP cameras
delivering rtsp h264 streams correctly. The non-keyframes are very blurry.
Plus, for media files as well as rtsp streams, I can only get half speed or
lower playback.
I’ll be posting a few questions about those issues later, but first I want to
ask about my implementation of an av_log callback, as I am getting crashes from
an “incorrect format specifier” delivered from the “h264” module. The specific
format string causing the crash is “error while decoding MB %d %d, bytestream
%td\n”. (Is the “t” size modifier valid in Visual Studio?)
void CE_LIBAV_Video::logging_callback(void *ptr, int level, const char *fmt,
va_list vargs)
{
static char message[8192];
const char *module = NULL;
if (level > AV_LOG_WARNING)
return;
// Get module name
if (ptr)
{
AVClass *avc = *(AVClass**) ptr;
module = avc->item_name(ptr);
}
// Create the actual message
vsnprintf_s(message, sizeof(message), _TRUNCATE, fmt, vargs);
ofstream log_file;
log_file.open( "libav.log", std::ios::app );
log_file << message;
log_file.close();
}
Playing USB video, I see no av_log format specifier issues. Playing media
files, non-h264, I see no av_log issues, but when playing an h264 video file I
also see the same format specifier issue.
I’m working in Win10, Visual Studio 2013 Community.
Sincerely,
-Blake Senftner
Mad Computer Scientist
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