When playing any 1080p60fps video content the video either stutters or stops playing but sound plays normaly. CPU usage is very low or erratic. I tried: disabling hardware acceleration, using an addon called h.264fy. Firefox Version: Firefox Nightly 60.0a1 (2018-02-11) (64-bit), fresh install with a newly created profile. PC specs: OS: Windows 7 Professional(SP1) 64-bit CPU: Intel Core 2 Duo E6550 OCed@2.8Ghz GPU: ATI Radeon 4870 512MB RAM: 4GB DRR2 perf.html link: https://perfht.ml/2H8dwfN about:support text Application Basics ------------------ Name: Firefox Version: 60.0a1 Build ID: 20180211220056 Update Channel: nightly User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0 OS: Windows_NT 6.1 Multiprocess Windows: 1/1 (Enabled by default) Web Content Processes: 3/4 Stylo: content = true (enabled by default), chrome = false (disabled by default) Google Key: Found Mozilla Location Service Key: Found Safe Mode: false Crash Reports for the Last 3 Days --------------------------------- All Crash Reports (including 23 pending crashes in the given time range) Nightly Features ---------------- Name: Activity Stream Version: 2018.02.09.1159-a77359dc ID: activity-stream@mozilla.org Name: Application Update Service Helper Version: 2.0 ID: aushelper@mozilla.org Name: Firefox Screenshots Version: 29.0.0 ID: screenshots@mozilla.org Name: Follow-on Search Telemetry Version: 0.9.6 ID: followonsearch@mozilla.com Name: Form Autofill Version: 1.0 ID: formautofill@mozilla.org Name: Photon onboarding Version: 1.0 ID: onboarding@mozilla.org Name: Pocket Version: 1.0.5 ID: firefox@getpocket.com Name: Presentation Version: 1.0.0 ID: presentation@mozilla.org Name: Shield Recipe Client Version: 83 ID: shield-recipe-client@mozilla.org Name: Web Compat Version: 1.1 ID: webcompat@mozilla.org Name: WebCompat Reporter Version: 1.0.0 ID: webcompat-reporter@mozilla.org Extensions ---------- Name: Gecko Profiler Version: 0.18 Enabled: true ID: geckoprofiler@mozilla.com Security Software ----------------- Type: Type: Type: Graphics -------- Features Compositing: Direct3D 11 (Advanced Layers) Asynchronous Pan/Zoom: wheel input enabled; scrollbar drag enabled; keyboard enabled; autoscroll enabled WebGL 1 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000008d6c) EGL_VERSION: 1.4 (ANGLE 2.1.0.db3422764a9b) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses EGL_ANGLE_display_robust_resource_initialization WebGL 1 Driver Renderer: Google Inc. -- ANGLE (ATI Radeon HD 4800 Series Direct3D11 vs_4_1 ps_4_1) WebGL 1 Driver Version: OpenGL ES 2.0 (ANGLE 2.1.0.db3422764a9b) WebGL 1 Driver Extensions: GL_ANGLE_client_arrays GL_ANGLE_depth_texture GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_robust_resource_initialization GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_minmax GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_frag_depth GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc_srgb GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context 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_vertex_array_object WebGL 1 Extensions: ANGLE_instanced_arrays EXT_blend_minmax EXT_color_buffer_half_float EXT_frag_depth EXT_sRGB EXT_shader_texture_lod EXT_texture_filter_anisotropic EXT_disjoint_timer_query OES_element_index_uint OES_standard_derivatives OES_texture_float OES_texture_float_linear OES_texture_half_float OES_texture_half_float_linear OES_vertex_array_object WEBGL_color_buffer_float WEBGL_compressed_texture_s3tc WEBGL_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_depth_texture WEBGL_draw_buffers WEBGL_lose_context WebGL 2 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000008d6c) EGL_VERSION: 1.4 (ANGLE 2.1.0.db3422764a9b) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses EGL_ANGLE_display_robust_resource_initialization WebGL 2 Driver Renderer: Google Inc. -- ANGLE (ATI Radeon HD 4800 Series Direct3D11 vs_4_1 ps_4_1) WebGL 2 Driver Version: OpenGL ES 3.0 (ANGLE 2.1.0.db3422764a9b) WebGL 2 Driver Extensions: GL_ANGLE_client_arrays GL_ANGLE_depth_texture GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_robust_resource_initialization GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource 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GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context 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_vertex_array_object WebGL 2 Extensions: EXT_color_buffer_float EXT_texture_filter_anisotropic EXT_disjoint_timer_query OES_texture_float_linear WEBGL_compressed_texture_s3tc WEBGL_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_lose_context Direct2D: true Off Main Thread Painting Enabled: true DirectWrite: true (6.2.9200.22164) GPU #1 Active: Yes Description: ATI Radeon HD 4800 Series Vendor ID: 0x1002 Device ID: 0x9440 Driver Version: 8.970.100.1100 Driver Date: 4-29-2013 Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64 Subsys ID: 00000000 RAM: 512 Diagnostics ClearType Parameters: 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Device): HDAUDIO\FUNC_01&VEN_1002&DEV_AA01&SUBSYS_00AA0100&REV_1001\5&e8e5247&2&0001 Center (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_18490890&REV_1001\4&2468e579&0&0001 Microphone (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_18490890&REV_1001\4&2468e579&0&0001 FrontMic (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_18490890&REV_1001\4&2468e579&0&0001 Front (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_18490890&REV_1001\4&2468e579&0&0001 Stereo Mix (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_18490890&REV_1001\4&2468e579&0&0001 Rear (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_18490890&REV_1001\4&2468e579&0&0001 CD Audio (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_18490890&REV_1001\4&2468e579&0&0001 Subwoofer (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_18490890&REV_1001\4&2468e579&0&0001 Important Modified Preferences ------------------------------ browser.cache.disk.capacity: 358400 browser.cache.disk.filesystem_reported: 1 browser.cache.disk.smart_size.first_run: false browser.places.smartBookmarksVersion: 8 browser.sessionstore.upgradeBackup.latestBuildID: 20180211220056 browser.startup.homepage_override.buildID: 20180211220056 browser.startup.homepage_override.mstone: 60.0a1 browser.urlbar.timesBeforeHidingSuggestionsHint: 0 dom.forms.autocomplete.formautofill: true extensions.lastAppVersion: 60.0a1 layers.mlgpu.sanity-test-failed: false media.benchmark.vp9.fps: 47 media.benchmark.vp9.versioncheck: 3 media.gmp-gmpopenh264.abi: x86_64-msvc-x64 media.gmp-gmpopenh264.lastUpdate: 1518446190 media.gmp-gmpopenh264.version: 1.7.1 media.gmp-manager.buildID: 20180211220056 media.gmp-manager.lastCheck: 1518447130 media.gmp-widevinecdm.abi: x86_64-msvc-x64 media.gmp-widevinecdm.lastUpdate: 1518446192 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Sorry you're having trouble with Firefox. Thanks for the report. Your screenshot doesn't look like it's displaying 1080p60. Does the problem happen with the default Youtube stream selection, or are you using the gear menu to force a higher resolution? What does the 'Stats for Nerds' overlay from the right-click menu on the video say about the codec and resolution when you see the stuttering?

(In reply to Ralph Giles (:rillian) | needinfo me from comment #1) > Sorry you're having trouble with Firefox. Thanks for the report. Your > screenshot doesn't look like it's displaying 1080p60. Does the problem > happen with the default Youtube stream selection, or are you using the gear > menu to force a higher resolution? What does the 'Stats for Nerds' overlay > from the right-click menu on the video say about the codec and resolution > when you see the stuttering? The video is indeed 1080p60fps. I'm having this problem with any 1080p60fps video on Firefox be it on YouTube or ony other website, lower resolutions e.g. 720p60fps and down do not have this problem. And this only happens with Firefox. I'll add a screenshot attachement to the OP showing the Stats for Nerds overlay.

Ok. thanks for for the addition information.