Fix for #3

[akssri-sony]

src/ffmpeg_decoder.cpp:

• check if hwdevice_ctx returns; else default to AV_HWDEVICE_TYPE_NONE.
• use SWS_ACCURATE_RND flag for non-aligned frames.

src/ffmpeg_encoder.cpp:

• use strided copy for non-aligned frame.

[berndpfrommer]

Does this PR fix issue #3 altogether? Or does it just allow to run with non-32-bytes line width?

[berndpfrommer]

The fails seem to be all formatting related. You can fix the formatting by running e.g.

clang-format -i ffmpeg_decoder.cpp

(You need to run this in the source tree such that clang-format finds the format config file)

[akssri-sony]

Apologies; have fixed the format now.

The PR fixes both issues:

• (decoder) If the av hardware context returns an error the default AV_HWDEVICE_TYPE_NONE gets used.
• (encoder) use strided copy to fix differing strides in opencv image and av frame.

[akssri-sony]

Ah! Forgot that this evaluates to (a == b) == c in CXX; fix pushed.

[berndpfrommer]

@akssri-sony Thank you for contributing this fix!