Add ffmpeg 6 support

[shssoichiro]

Closes #728

[shssoichiro]

@svenstaro It would be great if you could test this branch out before we merge it just to be safe. My personal machine is actually still on ffmpeg 5.1.

[svenstaro]

Doesn't actually build for me:

error[E0425]: cannot find value `AV_CODEC_FLAG_TRUNCATED` in this scope
   --> /home/svenstaro/.cargo/registry/src/github.com-1ecc6299db9ec823/ffmpeg-the-third-1.2.1+ffmpeg-6.0.0/src/codec/flag.rs:16:33
    |
16  |         const TRUNCATED       = AV_CODEC_FLAG_TRUNCATED;
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^ help: a constant with a similar name exists: `AV_CODEC_FLAG_DROPCHANGED`
    |
   ::: /home/svenstaro/src/Av1an/target/debug/build/ffmpeg-sys-the-third-ca32329f9e379525/out/bindings.rs:779:1
    |
779 | pub const AV_CODEC_FLAG_DROPCHANGED: libc::c_uint = 32;
    | ------------------------------------------------- similarly named constant `AV_CODEC_FLAG_DROPCHANGED` defined here

error[E0425]: cannot find value `AV_CODEC_CAP_TRUNCATED` in this scope
   --> /home/svenstaro/.cargo/registry/src/github.com-1ecc6299db9ec823/ffmpeg-the-third-1.2.1+ffmpeg-6.0.0/src/codec/capabilities.rs:9:37
    |
9   |         const TRUNCATED           = AV_CODEC_CAP_TRUNCATED;
    |                                     ^^^^^^^^^^^^^^^^^^^^^^ help: a constant with a similar name exists: `AV_CODEC_CAP_HARDWARE`
    |
   ::: /home/svenstaro/src/Av1an/target/debug/build/ffmpeg-sys-the-third-ca32329f9e379525/out/bindings.rs:741:1
    |
741 | pub const AV_CODEC_CAP_HARDWARE: libc::c_uint = 262144;
    | --------------------------------------------- similarly named constant `AV_CODEC_CAP_HARDWARE` defined here

error[E0425]: cannot find value `AV_CODEC_CAP_AUTO_THREADS` in this scope
   --> /home/svenstaro/.cargo/registry/src/github.com-1ecc6299db9ec823/ffmpeg-the-third-1.2.1+ffmpeg-6.0.0/src/codec/capabilities.rs:21:37
    |
21  |         const AUTO_THREADS        = AV_CODEC_CAP_AUTO_THREADS;
    |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^ help: a constant with a similar name exists: `AV_CODEC_CAP_FRAME_THREADS`
    |
   ::: /home/svenstaro/src/Av1an/target/debug/build/ffmpeg-sys-the-third-ca32329f9e379525/out/bindings.rs:735:1
    |
735 | pub const AV_CODEC_CAP_FRAME_THREADS: libc::c_uint = 4096;
    | -------------------------------------------------- similarly named constant `AV_CODEC_CAP_FRAME_THREADS` defined here

error[E0425]: cannot find value `AV_CODEC_CAP_INTRA_ONLY` in this scope
   --> /home/svenstaro/.cargo/registry/src/github.com-1ecc6299db9ec823/ffmpeg-the-third-1.2.1+ffmpeg-6.0.0/src/codec/capabilities.rs:26:37
    |
26  |         const INTRA_ONLY          = AV_CODEC_CAP_INTRA_ONLY;
    |                                     ^^^^^^^^^^^^^^^^^^^^^^^ help: a constant with a similar name exists: `AV_CODEC_PROP_INTRA_ONLY`
    |
   ::: /home/svenstaro/src/Av1an/target/debug/build/ffmpeg-sys-the-third-ca32329f9e379525/out/bindings.rs:746:1
    |
746 | pub const AV_CODEC_PROP_INTRA_ONLY: libc::c_int = 1;
    | ----------------------------------------------- similarly named constant `AV_CODEC_PROP_INTRA_ONLY` defined here

error[E0425]: cannot find value `AV_CODEC_CAP_LOSSLESS` in this scope
   --> /home/svenstaro/.cargo/registry/src/github.com-1ecc6299db9ec823/ffmpeg-the-third-1.2.1+ffmpeg-6.0.0/src/codec/capabilities.rs:28:37
    |
28  |         const LOSSLESS            = AV_CODEC_CAP_LOSSLESS;
    |                                     ^^^^^^^^^^^^^^^^^^^^^ help: a constant with a similar name exists: `AV_CODEC_PROP_LOSSLESS`
    |
   ::: /home/svenstaro/src/Av1an/target/debug/build/ffmpeg-sys-the-third-ca32329f9e379525/out/bindings.rs:748:1
    |
748 | pub const AV_CODEC_PROP_LOSSLESS: libc::c_int = 4;
    | --------------------------------------------- similarly named constant `AV_CODEC_PROP_LOSSLESS` defined here

error[E0609]: no field `thread_safe_callbacks` on type `sys::AVCodecContext`
   --> /home/svenstaro/.cargo/registry/src/github.com-1ecc6299db9ec823/ffmpeg-the-third-1.2.1+ffmpeg-6.0.0/src/codec/context.rs:106:38
    |
106 |                 (*self.as_mut_ptr()).thread_safe_callbacks = i32::from(config.safe);
    |                                      ^^^^^^^^^^^^^^^^^^^^^ unknown field
    |
    = note: available fields are: `av_class`, `log_level_offset`, `codec_type`, `codec`, `codec_id` ... and 154 others

error[E0609]: no field `thread_safe_callbacks` on type `sys::AVCodecContext`
   --> /home/svenstaro/.cargo/registry/src/github.com-1ecc6299db9ec823/ffmpeg-the-third-1.2.1+ffmpeg-6.0.0/src/codec/context.rs:117:40
    |
117 |                 safe: (*self.as_ptr()).thread_safe_callbacks != 0,
    |                                        ^^^^^^^^^^^^^^^^^^^^^ unknown field
    |
    = note: available fields are: `av_class`, `log_level_offset`, `codec_type`, `codec`, `codec_id` ... and 154 others

[svenstaro]

I'd report the failure upstream but @shssoichiro is upstream anyway. :)

[shssoichiro]

Should be working now. Mind giving it another try?

[svenstaro]

Works fine. Tested with a video and couldn't see regressions.

[shssoichiro]

@master-of-zen @redzic mind giving this the ol' green checkmark?

[svenstaro]

@master-of-zen Could you make a new release with this in it? Then I can bump the Arch package to ffmpeg 6.

[master-of-zen]

@svenstaro sure, will do that now

[master-of-zen]

@svenstaro done, 0.4.1 live