Test new version FFMPEG

[theogf]

As suggested in JuliaIO/FFMPEG.jl#59 (comment), this should test if VideoIO runs correctly with the new version o FFMPEG

[theogf]

This segfault does not look good 😅

[giordano]

For the benefit of future (and present) readers, the segmentation fault @theogf refers to is

[6222] signal (11.2): Segmentation fault: 11
in expression starting at /Users/runner/work/VideoIO.jl/VideoIO.jl/src/VideoIO.jl:203
av_freep at /Users/runner/.julia/artifacts/112745bebf2bab1be3313a35fda52d857c5b4ab4/lib/libavutil.58.29.100.dylib (unknown line)
avcodec_parameters_from_context at /Users/runner/.julia/artifacts/112745bebf2bab1be3313a35fda52d857c5b4ab4/lib/libavcodec.60.31.102.dylib (unknown line)

In particular, it's happening to

VideoIO.jl/src/VideoIO.jl

Line 208 in 0398aa6

VideoIO.save(fname, imgstack)

My loose understanding is that VideoIO use only CLI ffmpeg, so it shouldn't be too complicated to craft a reproducible example to report upstream for someone motivated to push for FFMPEG v6, otherwise we'd have to yank that version, if it's broken (and will also be stuck forever to v4 until someone else does that anyway)

[giordano]

Actually, I was looking for ccall in src/, but I just realised that there are thousands of ccalls in https://github.com/JuliaIO/VideoIO.jl/blob/0398aa6be81a1e637132a39136ebad94afd2f196/lib/libffmpeg.jl, I guess you'd need to update the generated wrappers, too. Side note, this means that VideoIO pretty much needs to specify FFMPEG_jll explicitly.

[giordano]

@theogf bump

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.34%. Comparing base (a2bc9a9) to head (ef6db25).

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[theogf]

Actually, I was looking for ccall in src/, but I just realised that there are thousands of ccalls in https://github.com/JuliaIO/VideoIO.jl/blob/0398aa6be81a1e637132a39136ebad94afd2f196/lib/libffmpeg.jl, I guess you'd need to update the generated wrappers, too. Side note, this means that VideoIO pretty much needs to specify FFMPEG_jll explicitly.

I am not sure what you mean here.
One wrapper is for example

function avcodec_decode_subtitle2(avctx, sub, got_sub_ptr, avpkt)
    ccall((:avcodec_decode_subtitle2, libavcodec), Cint, (Ptr{AVCodecContext}, Ptr{AVSubtitle}, Ptr{Cint}, Ptr{AVPacket}), avctx, sub, got_sub_ptr, avpkt)
end

Is the idea to just make sure that libavcodec directly comes from FFMPEG_jll? Or by update you mean to make sure that all wrappers are compatible with 6.1?

[giordano]

Or by update you mean to make sure that all wrappers are compatible with 6.1?

Yes, but you don't do that manually, but run the script in https://github.com/JuliaIO/VideoIO.jl/tree/42b25a21c0ec524d75bfead8209a0bfd61ca91b5/gen

[theogf]

So I generated libffmpeg.jl again, (also restricting the dependency to FFMPEG_jll). However I get the error

Failed to precompile VideoIO [d6d074c3-1acf-5d4c-9a43-ef38773959a2] to "/home/theo/.julia/compiled/v1.10/VideoIO/jl_nKnqkE".
ERROR: LoadError: UndefVarError: `AV_CHANNEL_LAYOUT_MASK` not defined

I located the corresponding C code here
https://github.com/FFmpeg/FFmpeg/blob/84e669167de9394e0de1bee0244f48ffac6f3826/libavutil/channel_layout.h#L378

But I don't know how to translate this to Julia? (and add it to prologue.jl)

[giordano]

That's a macro, it doesn't really have a correspondence in julia since it's a source-code transformation, not part of the ABI of the library. I don't know what's going on there.

[theogf]

That's a macro, it doesn't really have a correspondence in julia since it's a source-code transformation, not part of the ABI of the library. I don't know what's going on there.

Ah I think it's just some constructor for AVChannelLayout which is defined just above.

[giordano]

@Gnimuc do you have a clue how to deal with this? Clang.jl correctly defined the macros

VideoIO.jl/lib/libffmpeg.jl

Lines 22098 to 22104 in a9384d9

	const AV_CHANNEL_LAYOUT_MONO = AV_CHANNEL_LAYOUT_MASK(1, AV_CH_LAYOUT_MONO)
	const AV_CHANNEL_LAYOUT_STEREO = AV_CHANNEL_LAYOUT_MASK(2, AV_CH_LAYOUT_STEREO)
	const AV_CHANNEL_LAYOUT_2POINT1 = AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2POINT1)
	const AV_CHANNEL_LAYOUT_2_1 = AV_CHANNEL_LAYOUT_MASK(3, AV_CH_LAYOUT_2_1)

etc., but the macro AV_CHANNEL_LAYOUT_MASK has not been expanded.

[Gnimuc]

AV_CHANNEL_LAYOUT_MASK(nb, m) \
    { /* .order */ AV_CHANNEL_ORDER_NATIVE, \
      /* .nb_channels */  (nb), \
      /* .u.mask */ { m }, \
      /* .opaque */ NULL }

unfortunately, Clang.jl doesn't support such "convoluted" macros. Honestly, I don't even know how to manually translate this function-like macro into Julia...

if there is no direct use, it's safe to ignore all of the AV_CHANNEL* macro identifiers via the .toml file.

[giordano]

if there is no direct use, it's safe to ignore all of the AV_CHANNEL* macro identifiers via the .toml file.

Good point, it looks like all the AV_CHANNEL_LAYOUT_* macros are only defined in the resulting file, but not used. Thanks!

[theogf]

Just a small update, adding the right regex worked, but now there are some deprecated functions I need to find replacement for, namely av_stream_get_r_frame_rate

[theogf]

Hopefully it should work now 😅

[theogf]

Tests are failing so I can only assume that this is not the solution?

[IanButterworth]

This seems like the correct change based on https://patchwork.ffmpeg.org/project/ffmpeg/patch/20171023160821.6384-2-jamrial@gmail.com/

And the test failures could be rounding assumptions. Not looked deeper into it

Encoding with frame rate 29.5: Test Failed at /home/runner/work/VideoIO.jl/VideoIO.jl/test/writing.jl:196
  Expression: parse(Float64, measured_dur_str[1]) == target_dur
   Evaluated: 3.389831 == 3.39

Encoding with frame rate 29.5: Test Failed at /home/runner/work/VideoIO.jl/VideoIO.jl/test/writing.jl:214
  Expression: parse(Float64, measured_dur_str[1]) == target_dur
   Evaluated: 3.389831 == 3.39

[theogf]

We're a bit far from rounding error? Maybe it's a difference of 1 frame?