chrome incorrectly plays malformed webms (negative timestamps)
Reported by
bjo...@mozilla.com,
Oct 16 2017
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Issue descriptionUserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:58.0) Gecko/20100101 Firefox/58.0 Example URL: https://a.pomf.cat/oghcfk.webm Steps to reproduce the problem: 1. navigate to https://a.pomf.cat/oghcfk.webm What is the expected behavior? the webm should not play What went wrong? chrome plays the webm Did this work before? N/A Is it a problem with Flash or HTML5? HTML5 Does this work in other browsers? Yes Chrome version: Version 61.0.3163.100 (Official Build) (64-bit) Channel: n/a OS Version: OS X 10.13 Flash Version: Contents of chrome://gpu: Note: To properly save this page, select the "Webpage, Complete" option in the Save File dialog. Graphics Feature Status Canvas: Hardware accelerated CheckerImaging: Disabled Flash: Hardware accelerated Flash Stage3D: Hardware accelerated Flash Stage3D Baseline profile: Hardware accelerated Compositing: Hardware accelerated Multiple Raster Threads: Enabled Native GpuMemoryBuffers: Hardware accelerated Rasterization: Hardware accelerated Video Decode: Hardware accelerated Video Encode: Hardware accelerated WebGL: Hardware accelerated WebGL2: Hardware accelerated Driver Bug Workarounds adjust_src_dst_region_for_blitframebuffer decode_encode_srgb_for_generatemipmap disable_framebuffer_cmaa disable_multimonitor_multisampling get_frag_data_info_bug msaa_is_slow pack_parameters_workaround_with_pack_buffer regenerate_struct_names remove_invariant_and_centroid_for_essl3 scalarize_vec_and_mat_constructor_args set_zero_level_before_generating_mipmap unfold_short_circuit_as_ternary_operation unpack_alignment_workaround_with_unpack_buffer use_intermediary_for_copy_texture_image use_unused_standard_shared_blocks Problems Detected Multisampling is buggy on OSX when multiple monitors are connected: 237931 Applied Workarounds: disable_multimonitor_multisampling Unfold short circuit on Mac OS X: 307751 Applied Workarounds: unfold_short_circuit_as_ternary_operation Always rewrite vec/mat constructors to be consistent: 398694 Applied Workarounds: scalarize_vec_and_mat_constructor_args Mac drivers handle struct scopes incorrectly: 403957 Applied Workarounds: regenerate_struct_names glGenerateMipmap fails if the zero texture level is not set on some Mac drivers: 560499 Applied Workarounds: set_zero_level_before_generating_mipmap Pack parameters work incorrectly with pack buffer bound: 563714 Applied Workarounds: pack_parameters_workaround_with_pack_buffer Alignment works incorrectly with unpack buffer bound: 563714 Applied Workarounds: unpack_alignment_workaround_with_unpack_buffer copyTexImage2D fails when reading from IOSurface on multiple GPU types.: 581777 Applied Workarounds: use_intermediary_for_copy_texture_image Limited enabling of Chromium GL_INTEL_framebuffer_CMAA: 535198 Applied Workarounds: disable_framebuffer_cmaa glGetFragData{Location|Index} works incorrectly on Max: 638340 Applied Workarounds: get_frag_data_info_bug Decode and encode before generateMipmap for srgb format textures on macosx: 634519 Applied Workarounds: decode_encode_srgb_for_generatemipmap Insert statements to reference all members in unused std140/shared blocks on Mac: 618464 Applied Workarounds: use_unused_standard_shared_blocks adjust src/dst region if blitting pixels outside read framebuffer on Mac: 644740 Applied Workarounds: adjust_src_dst_region_for_blitframebuffer Mac driver GL 4.1 requires invariant and centroid to match between shaders: 639760, 641129 Applied Workarounds: remove_invariant_and_centroid_for_essl3 Disable KHR_blend_equation_advanced until cc shaders are updated: 661715 On Intel GPUs MSAA performance is not acceptable for GPU rasterization: 527565, 751919 Applied Workarounds: msaa_is_slow Checker-imaging has been disabled via finch trial or the command line. Disabled Features: checker_imaging Version Information Data exported 16/10/2017, 15:39:22 Chrome version Chrome/61.0.3163.100 Operating system Mac OS X 10.13.0 Software rendering list version 13.10 Driver bug list version 10.29 ANGLE commit id 0d2ecb4ea992 2D graphics backend Skia/61 0eefc0552cfb5ac077560b7c2630c5bd475ea585- Command Line /Applications/Google Chrome.app/Contents/MacOS/Google Chrome --flag-switches-begin --flag-switches-end Driver Information Initialization time 52 In-process GPU false Passthrough Command Decoder false Supports overlays false Sandboxed true GPU0 VENDOR = 0x1002, DEVICE= 0x67ef *ACTIVE* GPU1 VENDOR = 0x8086, DEVICE= 0x191b Optimus false Optimus false AMD switchable true Driver vendor Driver version 1.58.30 Driver date Pixel shader version 4.10 Vertex shader version 4.10 Max. MSAA samples 8 Machine model name MacBookPro Machine model version 13.3 GL_VENDOR ATI Technologies Inc. GL_RENDERER AMD Radeon Pro 460 OpenGL Engine GL_VERSION 4.1 ATI-1.58.30 GL_EXTENSIONS GL_ARB_blend_func_extended GL_ARB_draw_buffers_blend GL_ARB_draw_indirect GL_ARB_ES2_compatibility GL_ARB_explicit_attrib_location GL_ARB_gpu_shader_fp64 GL_ARB_gpu_shader5 GL_ARB_instanced_arrays GL_ARB_internalformat_query GL_ARB_occlusion_query2 GL_ARB_sample_shading GL_ARB_sampler_objects GL_ARB_separate_shader_objects GL_ARB_shader_bit_encoding GL_ARB_shader_subroutine GL_ARB_shading_language_include GL_ARB_tessellation_shader GL_ARB_texture_buffer_object_rgb32 GL_ARB_texture_cube_map_array GL_ARB_texture_gather GL_ARB_texture_query_lod GL_ARB_texture_rgb10_a2ui GL_ARB_texture_storage GL_ARB_texture_swizzle GL_ARB_timer_query GL_ARB_transform_feedback2 GL_ARB_transform_feedback3 GL_ARB_vertex_attrib_64bit GL_ARB_vertex_type_2_10_10_10_rev GL_ARB_viewport_array GL_EXT_debug_label GL_EXT_debug_marker GL_EXT_depth_bounds_test GL_EXT_texture_compression_s3tc GL_EXT_texture_filter_anisotropic GL_EXT_texture_mirror_clamp GL_EXT_texture_sRGB_decode GL_APPLE_client_storage GL_APPLE_container_object_shareable GL_APPLE_flush_render GL_APPLE_object_purgeable GL_APPLE_rgb_422 GL_APPLE_row_bytes GL_APPLE_texture_range GL_ATI_texture_mirror_once GL_NV_texture_barrier Disabled Extensions GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent Window system binding vendor Window system binding version Window system binding extensions Direct rendering Yes Reset notification strategy 0x0000 GPU process crash count 0 Compositor Information Tile Update Mode Zero-copy Partial Raster Enabled GpuMemoryBuffers Status ATC Software only ATCIA Software only DXT1 Software only DXT5 Software only ETC1 Software only R_8 GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT R_16 Software only RG_88 Software only BGR_565 Software only RGBA_4444 Software only RGBX_8888 Software only RGBA_8888 GPU_READ, SCANOUT, SCANOUT_CPU_READ_WRITE BGRX_8888 GPU_READ, SCANOUT, SCANOUT_CPU_READ_WRITE BGRA_8888 GPU_READ, SCANOUT, SCANOUT_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT RGBA_F16 GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT YVU_420 Software only YUV_420_BIPLANAR GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT UYVY_422 GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT the first frame of the webm has a negative timestamp: SimpleBlock (key, track number 2, 1 frame(s), timestamp -0.001s = -00:00:00.001) this is not allowed as per the webm specifications – chrome should reject the file as invalid. https://matroska.org/technical/specs/notes.html "Blocks with a negative Raw Timecode are not valid." see also: https://bugzilla.mozilla.org/show_bug.cgi?id=868797
,
Oct 17 2017
,
Oct 26 2017
Sorry to chime in, but I would seriously advise against changing this. This behavior has been in Chrome/Chromium for at minimum five years, probably more. I say five because there is a Firefox bug (the one in the reporter's post) about *not* being able to play these videos from five years ago, and since then there has been around a dozen confirmed duplicates which link or attach sample videos from all over the web. Some of these videos are on high-profile websites like Steam, one was on NYmag.com, and there's others that may be a bit more niche (there's also some popular NSFW websites with videos that have this issue, not sure if you care about those). For years these videos have played in Chrome/Chromium and not Firefox, and the issue looks like it might be fixed soon in Firefox, and now you seem to be talking about breaking playback of these videos. The reality is this is much like dealing with weirdly formatted HTML and so on, which browsers have had to deal with. This has been in the wild for too long to patch it now. The mozilla bug the original reporter in this thread links to has all the duplicates I mentioned, you'll find all the examples on various websites there. At this point, breaking this just means that Chromium will be degraded in functionality just like Firefox has been, which will be pretty frustrating for many websites. Offline video players are already used to having to play broken files, it just comes with the territory. Or rather, given how much "quirks mode" handling browsers have to do, I would imagine you guys already understand how standards don't always get implemented perfectly; breaking playback on the web after over five years of these videos working fine should not be on the table.
,
Nov 29 2017
ffmpeg doesn't report this as a negative timestamp; it doesn't seem to agree that the timecode is negative. I also can't find any code that would fixup the negative time codes, so marking as WontFix. Presumably the calculation ffmpeg uses avoids having a negative timestamp. Here are the first audio/video packets: [PACKET] codec_type=audio stream_index=1 pts=0 pts_time=0.000000 dts=0 dts_time=0.000000 duration=2 duration_time=0.002000 convergence_duration=N/A convergence_duration_time=N/A size=1 pos=4486 flags=K_ [/PACKET] [PACKET] codec_type=video stream_index=0 pts=16 pts_time=0.016000 dts=16 dts_time=0.016000 duration=16 duration_time=0.016000 convergence_duration=N/A convergence_duration_time=N/A size=83639 pos=4509 flags=K_ [/PACKET] |
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Comment 1 by dalecur...@chromium.org
, Oct 16 2017Owner: dalecur...@chromium.org
Status: Assigned (was: Unconfirmed)