FFMPEG avformat_open_input returned error

Question

Sorry I have to ask this question, but I couldn't find a reference to the return codes of avformat_open_input, and I couldn't find anyone asking/answering about mine.

After this call to the function

err = avformat_open_input(&pFormatCtx, is->filename, NULL, NULL);

I get err = -13. What does it mean, and if anybody answers, please also share how you know which code corresponds to which error.

UPDATE: OK, I finally figured out how to turn the code into a message, and the message is "Permission denied". Does anyone have an idea where the problem with this might be?

Answer 1

1. See libavutil/error.h for the error code definitions, but they mostly match negative errno values. You can use av_strerror function to get the meaningful message.

2. "Permission denied" most likely means the file you point to in is->filename could not be opened due to permissions. Run strace on your app if you think this isn't the case.