UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.81 Safari/537.36

Example URL:
https://www.youtube.com/watch?v=SChPyFtAKI8

Steps to reproduce the problem:
1. Enable VAAPI in Chromium (I'm using chromium-vaapi-bin from AUR).
2. Install the h264ify extension if necessary.
3. Launch chromium with --use-gl=egl
4. Play a video, eg from youtube.

What is the expected behavior?
The video should play smoothly.

What went wrong?
The video stutters as if some frames are being skipped, duplicated and/or presented in the wrong order. CPU usage is similar to when it's working correctly without the egl flag ie significantly better than when using CPU only, but still a lot higher than a standalone player, such as mpv, with VAAPI.

Did this work before? N/A 

Is it a problem with Flash or HTML5? HTML5

Does this work in other browsers? Yes

Chrome version: 69.0.3497.81  Channel: n/a
OS Version: Arch
Flash Version: 

Contents of chrome://gpu: 

Graphics Feature Status
Canvas: Hardware accelerated
Flash: Hardware accelerated
Flash Stage3D: Hardware accelerated
Flash Stage3D Baseline profile: Hardware accelerated
Compositing: Hardware accelerated
Multiple Raster Threads: Enabled
Native GpuMemoryBuffers: Software only. Hardware acceleration disabled
Out-of-process Rasterization: Disabled
Hardware Protected Video Decode: Hardware accelerated
Rasterization: Hardware accelerated
Skia Deferred Display List: Disabled
Skia Renderer: Disabled
Surface Synchronization: Enabled
Video Decode: Hardware accelerated
Viz Service Display Compositor: Disabled
WebGL: Hardware accelerated
WebGL2: Hardware accelerated
Driver Bug Workarounds
adjust_src_dst_region_for_blitframebuffer
clear_uniforms_before_first_program_use
count_all_in_varyings_packing
disable_framebuffer_cmaa
disable_post_sub_buffers_for_onscreen_surfaces
msaa_is_slow
scalarize_vec_and_mat_constructor_args
Problems Detected
Clear uniforms before first program use on all platforms: 124764, 349137
Applied Workarounds: clear_uniforms_before_first_program_use
Mesa drivers in Linux handle varyings without static use incorrectly: 333885
Applied Workarounds: count_all_in_varyings_packing
Disable partial swaps on Mesa drivers (detected with GL_RENDERER): 339493
Applied Workarounds: disable_post_sub_buffers_for_onscreen_surfaces
Always rewrite vec/mat constructors to be consistent: 398694
Applied Workarounds: scalarize_vec_and_mat_constructor_args
On Intel GPUs MSAA performance is not acceptable for GPU rasterization: 527565
Applied Workarounds: msaa_is_slow
Timer queries crash on Intel GPUs on Linux: 540543, 576991
Applied Workarounds: disable(GL_ARB_timer_query), disable(GL_EXT_timer_query)
Use GL_INTEL_framebuffer_CMAA on ChromeOS: 535198
Applied Workarounds: disable_framebuffer_cmaa
Disable partial swaps on Mesa drivers (detected with GL_VERSION): 339493
Applied Workarounds: disable_post_sub_buffers_for_onscreen_surfaces
adjust src/dst region if blitting pixels outside read framebuffer on Linux Intel: 664740
Applied Workarounds: adjust_src_dst_region_for_blitframebuffer
Disable KHR_blend_equation_advanced until cc shaders are updated: 661715
Applied Workarounds: disable(GL_KHR_blend_equation_advanced), disable(GL_KHR_blend_equation_advanced_coherent)
Don't expose disjoint_timer_query extensions to WebGL: 808744
Native GpuMemoryBuffers have been disabled, either via about:flags or command line.
Disabled Features: native_gpu_memory_buffers
Viz service display compositor is not enabled by default.
Disabled Features: viz_display_compositor
Skia renderer is not used by default.
Disabled Features: skia_renderer
Skia deferred display list is not used by default.
Disabled Features: skia_deferred_display_list
Version Information
Data exported	2018-09-16T10:38:27.208Z
Chrome version	Chrome/69.0.3497.81
Operating system	Linux 4.18.7-arch1-1-ARCH
Software rendering list URL	https://chromium.googlesource.com/chromium/src/+/032b3ca19e9af20182f9bd03deefc0faf4695558/gpu/config/software_rendering_list.json
Driver bug list URL	https://chromium.googlesource.com/chromium/src/+/032b3ca19e9af20182f9bd03deefc0faf4695558/gpu/config/gpu_driver_bug_list.json
ANGLE commit id	unknown hash
2D graphics backend	Skia/69 e110fd1ebd2d559838c49a8821ebf18986bd6ec2-
Command Line	/usr/lib/chromium/chromium --use-gl=egl --flag-switches-begin --enable-accelerated-video --enable-gpu-rasterization --ignore-gpu-blacklist --flag-switches-end
Driver Information
Initialization time	32
In-process GPU	false
Passthrough Command Decoder	false
Sandboxed	false
GPU0	VENDOR = 0x8086 [Intel Open Source Technology Center], DEVICE= 0x1916 [Mesa DRI Intel(R) HD Graphics 520 (Skylake GT2) ] *ACTIVE*
Optimus	false
AMD switchable	false
Driver vendor	Mesa
Driver version	18.2.0
Driver date	
Pixel shader version	3.20
Vertex shader version	3.20
Max. MSAA samples	16
Machine model name	
Machine model version	
GL_VENDOR	Intel Open Source Technology Center
GL_RENDERER	Mesa DRI Intel(R) HD Graphics 520 (Skylake GT2)
GL_VERSION	OpenGL ES 3.2 Mesa 18.2.0
GL_EXTENSIONS	GL_ANDROID_extension_pack_es31a GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_APPLE_texture_max_level GL_EXT_base_instance GL_EXT_blend_func_extended GL_EXT_blend_minmax GL_EXT_buffer_storage GL_EXT_clip_cull_distance GL_EXT_color_buffer_float GL_EXT_compressed_ETC1_RGB8_sub_texture GL_EXT_copy_image GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_draw_buffers_indexed GL_EXT_draw_elements_base_vertex GL_EXT_frag_depth GL_EXT_geometry_point_size GL_EXT_geometry_shader GL_EXT_gpu_shader5 GL_EXT_map_buffer_range GL_EXT_multi_draw_arrays GL_EXT_occlusion_query_boolean GL_EXT_polygon_offset_clamp GL_EXT_primitive_bounding_box GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_separate_shader_objects GL_EXT_shader_framebuffer_fetch GL_EXT_shader_framebuffer_fetch_non_coherent GL_EXT_shader_integer_mix GL_EXT_shader_io_blocks GL_EXT_shader_samples_identical GL_EXT_tessellation_point_size GL_EXT_tessellation_shader GL_EXT_texture_border_clamp GL_EXT_texture_buffer GL_EXT_texture_compression_dxt1 GL_EXT_texture_cube_map_array GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_norm16 GL_EXT_texture_rg GL_EXT_texture_sRGB_decode GL_EXT_texture_type_2_10_10_10_REV GL_EXT_unpack_subimage GL_INTEL_conservative_rasterization GL_INTEL_performance_query GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent GL_KHR_context_flush_control GL_KHR_debug GL_KHR_no_error GL_KHR_robust_buffer_access_behavior GL_KHR_robustness GL_KHR_texture_compression_astc_ldr GL_KHR_texture_compression_astc_sliced_3d GL_MESA_framebuffer_flip_y GL_MESA_shader_integer_functions GL_NV_draw_buffers GL_NV_fbo_color_attachments GL_NV_image_formats GL_NV_read_buffer GL_NV_read_depth GL_NV_read_depth_stencil GL_NV_read_stencil GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_EGL_image_external_essl3 GL_OES_EGL_sync GL_OES_compressed_ETC1_RGB8_texture GL_OES_copy_image GL_OES_depth24 GL_OES_depth_texture GL_OES_depth_texture_cube_map GL_OES_draw_buffers_indexed GL_OES_draw_elements_base_vertex GL_OES_element_index_uint GL_OES_fbo_render_mipmap GL_OES_geometry_point_size GL_OES_geometry_shader GL_OES_get_program_binary GL_OES_gpu_shader5 GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_primitive_bounding_box GL_OES_required_internalformat GL_OES_rgb8_rgba8 GL_OES_sample_shading GL_OES_sample_variables GL_OES_shader_image_atomic GL_OES_shader_io_blocks GL_OES_shader_multisample_interpolation GL_OES_standard_derivatives GL_OES_stencil8 GL_OES_surfaceless_context GL_OES_tessellation_point_size GL_OES_tessellation_shader GL_OES_texture_3D GL_OES_texture_border_clamp GL_OES_texture_buffer GL_OES_texture_cube_map_array GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_texture_stencil8 GL_OES_texture_storage_multisample_2d_array GL_OES_texture_view GL_OES_vertex_array_object GL_OES_vertex_half_float GL_OES_viewport_array
Disabled Extensions	GL_ARB_timer_query GL_EXT_timer_query GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent
Disabled WebGL Extensions	EXT_disjoint_timer_query EXT_disjoint_timer_query_webgl2
Window system binding vendor	Mesa Project
Window system binding version	1.4 (DRI2)
Window system binding extensions	EGL_ANDROID_blob_cache EGL_ANDROID_native_fence_sync EGL_CHROMIUM_sync_control EGL_EXT_buffer_age EGL_EXT_create_context_robustness EGL_EXT_image_dma_buf_import EGL_EXT_image_dma_buf_import_modifiers EGL_IMG_context_priority EGL_KHR_config_attribs EGL_KHR_create_context EGL_KHR_create_context_no_error EGL_KHR_fence_sync EGL_KHR_get_all_proc_addresses EGL_KHR_gl_colorspace EGL_KHR_gl_renderbuffer_image EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_3D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_image EGL_KHR_image_base EGL_KHR_image_pixmap EGL_KHR_no_config_context EGL_KHR_reusable_sync EGL_KHR_surfaceless_context EGL_EXT_pixel_format_float EGL_KHR_wait_sync EGL_MESA_configless_context EGL_MESA_drm_image EGL_MESA_image_dma_buf_export EGL_NOK_texture_from_pixmap EGL_WL_bind_wayland_display
Window manager	GNOME Shell
XDG_CURRENT_DESKTOP	GNOME
GDMSESSION	gnome-xorg
Compositing manager	Yes
Direct rendering	Yes
Reset notification strategy	0x8252
GPU process crash count	0
System visual ID	0
RGBA visual ID	0
Compositor Information
Tile Update Mode	One-copy
Partial Raster	Enabled
GpuMemoryBuffers Status
ATC	Software only
ATCIA	Software only
DXT1	Software only
DXT5	Software only
ETC1	Software only
R_8	Software only
R_16	Software only
RG_88	Software only
BGR_565	Software only
RGBA_4444	Software only
RGBX_8888	Software only
RGBA_8888	Software only
BGRX_8888	Software only
BGRX_1010102	Software only
RGBX_1010102	Software only
BGRA_8888	Software only
RGBA_F16	Software only
YVU_420	Software only
YUV_420_BIPLANAR	Software only
UYVY_422	Software only
Display(s) Information
Info	Display[14822516254048322] bounds=[0,0 1422x800], workarea=[0,27 1422x772], scale=1.8, external.
Color space information	{primaries_d50_referred: [[0.6512, 0.3208], [0.3150, 0.6062], [0.1603, 0.0668]], transfer:0.0000*x + 0.0000 if x < 0.0000 else (1.0000*x + 0.0000)**2.2000 + 0.0000, matrix:RGB, range:FULL}
Bits per color component	8
Bits per pixel	24
Video Acceleration Information
Decode h264 baseline	up to 4096x4096 pixels
Decode h264 main	up to 4096x4096 pixels
Decode h264 high	up to 4096x4096 pixels
Decode vp8	up to 4096x4096 pixels
Encode h264 baseline	up to 4096x4096 pixels and/or 30.000 fps
Encode h264 main	up to 4096x4096 pixels and/or 30.000 fps
Encode h264 high	up to 4096x4096 pixels and/or 30.000 fps
Log Messages
[28825:28825:0916/111721.996668:ERROR:sandbox_linux.cc(379)] : InitializeSandbox() called with multiple threads in process gpu-process.
[28825:28825:0916/111728.991708:ERROR:texture_manager.cc(3410)] : [.BrowserCompositor-0x1f74fca20e00]GL ERROR :GL_INVALID_ENUM : glTexImage2D: <- error from previous GL command

Chromium's VAAPI works properly in X11 without forcing EGL, but in Wayland one has to patch va to use DRI3 (https://github.com/intel/libva/pull/180 and https://github.com/intel/intel-vaapi-driver/pull/369) and use Chromium's --use-gl=egl flag. Without the latter the video surface stays black.

The problem seems specific to forcing EGL, I can reproduce it with the dri3 patches reverted. Either way, X11 is also affected, not only Wayland.

I can't reproduce the probem in other video players, totem and mpv.

In Chromium the problem seems specific to VAAPI. WebGL canvases and software video playback seem unaffected.