error: ‘avcodec_send_packet’ was not declared in this scope - gcc

Question

The following snippet of ffmpeg-based code is building and working on Windows VC2012, VC20155, VC2017.
With gcc on Ubuntu LTS 16.04 this is giving me issues, more specifically it does not seem to recognize avcodec_send_packet, avcodec_receive_frame and struct AVCodecParameters, and possibly more functions and structures that I'm not currently using.
error: ‘AVCodecParameters’ was not declared in this scope
error: ‘avcodec_send_packet’ was not declared in this scope
error: ‘avcodec_receive_frame ’ was not declared in this scope
The code snippet is:
// the includes are actually in a precompiled header, included in cmake
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavdevice/avdevice.h>
#include <libavfilter/avfilter.h>
#include <libpostproc/postprocess.h>
#include <libswresample/swresample.h>
#include <libswscale/swscale.h>
#include <libavformat/avformat.h>
#include <libavutil/avutil.h>
#include <libavutil/avassert.h>
#include <libavutil/avstring.h>
#include <libavutil/bprint.h>
#include <libavutil/display.h>
#include <libavutil/mathematics.h>
#include <libavutil/imgutils.h>
//#include <libavutil/libm.h>
#include <libavutil/parseutils.h>
#include <libavutil/pixdesc.h>
#include <libavutil/eval.h>
#include <libavutil/dict.h>
#include <libavutil/opt.h>
#include <libavutil/cpu.h>
#include <libavutil/ffversion.h>
#include <libavutil/version.h>
}
//
...
{
if (av_read_frame(m_FormatContext, m_Packet) < 0) {
av_packet_unref(m_Packet);
m_AllPacketsSent = true;
} else {
if (m_Packet->stream_index == m_StreamIndex) {
avcodec_send_packet(m_CodecContext, m_Packet);
}
}
}
...
I read up on the ffmpeg history and learned that on Debian based systems at one point they followed the fork to libavutil when that came about, and then recently some of the platforms switched back to the ffmpeg branch due to the fact that ffmpeg was much more actively supported in terms of bugfixes, features and support. As a result, some of the interfaces were possibly broken.
I've seen git fixes on a library called mediatombs who seem to have ecountered the same if not very similar issues with codecpar (which I initially also had and fixed the same way):
https://github.com/gerbera/gerbera/issues/52
https://github.com/gerbera/gerbera/commit/32efd463f138557c54535225d84136df95bab3dd#diff-af3b638bc2a3e6c650974192a53c7291
Here the commit seems to fix their specific issue by wrapping the codecpar field that is being renamed back to codec, which I also applied and works.
I wonder if anyone knows which functions can be used for the errors given above, since in fact these functions are themselves replacing deprecated functionality according the ffmpeg avcodec.h header comments. (https://www.ffmpeg.org/doxygen/trunk/avcodec_8h_source.html). I hope this does not mean I would have to settle back into avcodec_encode_video2() type of functions?
Update:
For reference, it seems it has also popped up here: https://github.com/Motion-Project/motion/issues/338. The issue seems to be resolved if you can rebuild your ffmpeg stack.
Update:
To resolve the version API mingle, I ended up wiping out any ffmpeg reference and rebuilding ffmpeg from sources. This seems to push things further along in the right direction; I have my source compiling correctly but there is still something wrong with the way I'm linking things together.
Also, I'm using CMake to set up my makefiles, and using find_package for some of the dependencies and handwritten find_path / find_library stuff for everything else. I've seen other people complain about the following linking issue, and a ton of case-specific replies but none of them really shed some light on what the actual problem is. My installed Ubuntu version of ALSA is 1.1.xx but still I get complaints about a 0.9 version I'm supposedly linking. Anyone knows what's wrong with this?
Also, my libasound.so is symbol linked into libasound.so.2.0.0 if that clears anything up. (Hope that double slashed path at the end is correct also).
/usr/bin/ld: /usr/lib/ffmpeg/libavdevice.a(alsa.o): undefined reference to symbol 'snd_pcm_hw_params_any##ALSA_0.9' //usr/lib/x86_64-linux-gnu/libasound.so.2:

Answer 1

So the problem was indeed a version mixup of avcodec and ffmpeg sources, where I would be linking to the right library but compiled against the wrong source package. I found out by following Andrew's suggestion to check the API versions in the header.
The solution was, as halfelf suggested, to uninstall both ffmpeg and avcodec and then manually download the source trunk from the latest repository version of ffmpeg, and build from source. This is quite a process, but it all worked out and resolved the linking issue.