avformat constify commit

[Mr-Dave]

Summary of the bug:

It seems the commits in the git master around 14fa0a4efbc989619860ed8ec0fd33dcdae558b0
now prevent the normal use of the api. The following is a sample that was previously functional for setting up a MP4 container with HEVC.

#include <libavformat/avformat.h>
int main (int argc, const char argv) {

AVFormatContext *format_context;

format_context = avformat_alloc_context();
format_context->oformat = av_guess_format("mp4", NULL, NULL);
format_context->oformat->video_codec = AV_CODEC_ID_HEVC;

avformat_close_input(&format_context);

return 0;

}

Compiler message:

error: assignment of member ‘video_codec’ in read-only object

format_context->oformat->video_codec = AV_CODEC_ID_HEVC;

[Cigaes]

That code was never valid. Maybe it worked by chance (but actually probably not), but it is not how you are supposed to use the API.