Cannot find x264 codec device for FFmpeg transcoding

[Tom Ato]

I am messing around with an FFmpeg transcoding tutorial (source: https://ffmpeg.org/doxygen/trunk/transcoding_8c-example.html)

I am using FFmpeg 4.0.5 and built it successfully as follows:

$ sudo apt-get install libx264-dev
$ cd ffmpeg-4.0.5
$ ./configure --prefix=buildout --enable-shared --disable-static --disable-doc --enable-gpl --disable-opencl --enable-libx264
$ make
$ sudo make install
$ sudo ldconfig
I have been looking at an article as well for guidance. (http://www.programmersought.com/article/71051173025/;jsessionid=2D01469BCFABF65530FCC81DBC04E9C0)

The transcoding.c source file does compile:

$ gcc transcoding.c -o out -lavformat -lavcodec -lavutil -lavfilter
Calling the executable is straight-forward:

$ ./out $INPUT_VIDEO $OUTPUT_VIDEO
where $INPUT_VIDEO is an mp4 container (h264/aac)

Up until this point everything appears to be working on my Debian 10 VM (if that is relevant). However, I get the following erroneous output:

[h264_v4l2m2m @ 0x564f664eebc0] Could not find a valid device
[h264_v4l2m2m @ 0x564f664eebc0] can't configure encoder
Cannot open video encoder for stream #0
Error occurred: Invalid argument
The article I attached says I need to add it when compiling FFmpeg, so I changed the ./configure line to as above, but to no avail. Any help or guidance would be appreciated.

[october262]

someone has replied to your other post here - https://stackoverflow.com/questions/60201557/cannot-find-x264-codec-device-for-ffmpeg-transcoding

[sophisticles]

You built ffmpeg just fine, you just aren't calling it correctly:

https://trac.ffmpeg.org/wiki/Encode/H.264