From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id F3A3B44839 for ; Mon, 26 Sep 2022 07:58:44 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 4027B68B9A4; Mon, 26 Sep 2022 10:58:41 +0300 (EEST) Received: from mail0.khirnov.net (red.khirnov.net [176.97.15.12]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 1DBE668B61A for ; Mon, 26 Sep 2022 10:58:35 +0300 (EEST) Received: from localhost (localhost [IPv6:::1]) by mail0.khirnov.net (Postfix) with ESMTP id E6DDE240183 for ; Mon, 26 Sep 2022 09:58:33 +0200 (CEST) Received: from mail0.khirnov.net ([IPv6:::1]) by localhost (mail0.khirnov.net [IPv6:::1]) (amavisd-new, port 10024) with ESMTP id Law4Cbc3YiaT for ; Mon, 26 Sep 2022 09:58:33 +0200 (CEST) Received: from lain.khirnov.net (lain.khirnov.net [IPv6:2001:67c:1138:4306::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "lain.khirnov.net", Issuer "smtp.khirnov.net SMTP CA" (verified OK)) by mail0.khirnov.net (Postfix) with ESMTPS id 5CF9E2400F4 for ; Mon, 26 Sep 2022 09:58:33 +0200 (CEST) Received: by lain.khirnov.net (Postfix, from userid 1000) id 634A21601B2; Mon, 26 Sep 2022 09:58:33 +0200 (CEST) From: Anton Khirnov To: FFmpeg development discussions and patches In-Reply-To: References: Mail-Followup-To: FFmpeg development discussions and patches Date: Mon, 26 Sep 2022 09:58:33 +0200 Message-ID: <166417911337.22057.14198719724356475476@lain.khirnov.net> User-Agent: alot/0.8.1 MIME-Version: 1.0 Subject: Re: [FFmpeg-devel] Bug on Bayer conversions X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: Quoting Chema Gonzalez (2022-09-25 17:54:16) > Hi, > > I found an issue while playing with Bayer pixel format conversions. > > ``` > $ echo -ne '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff' > > image.raw > $ xxd image.raw > 00000000: 0000 0000 0000 0000 0000 0000 0000 0000 ................ > 00000010: 0000 0000 0000 0000 0000 0000 0000 0000 ................ > 00000020: ffff ffff ffff ffff ffff ffff ffff ffff ................ > 00000030: ffff ffff ffff ffff ffff ffff ffff ffff ................ > ``` > > And then: > ``` > $ ffmpeg -y -f rawvideo -pixel_format bayer_bggr8 -s 8x8 -i image.raw > -f rawvideo -pix_fmt rgb24 -video_size 8x8 image.raw.rgb > ... > Assertion srcSliceH > 1 failed at libswscale/swscale_unscaled.c:1310 > Aborted (core dumped)ated 2 times > ``` > > The issue relates to the ffmpeg parallelization. > ``` > $ ffmpeg -y -filter_threads 1 -f rawvideo -pixel_format bayer_bggr8 -s > 8x8 -i image.raw -f rawvideo -pix_fmt rgb24 -video_size 8x8 > image.raw.rgb > ... > frame= 1 fps=0.0 q=-0.0 Lsize= 0kB time=00:00:00.00 > bitrate=N/A speed= 0x eed=N/A > video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB > muxing overhead: 0.000000% > $ xxd image.raw.rgb > 00000000: 0000 0000 0000 0000 0000 0000 0000 0000 ................ > 00000010: 0000 0000 0000 0000 0000 0000 0000 0000 ................ > 00000020: 0000 0000 0000 0000 0000 0000 0000 0000 ................ > 00000030: 0000 0000 0000 0000 0000 0000 0000 0000 ................ > 00000040: 0000 0000 0000 0000 0000 0000 0000 0000 ................ > 00000050: 7f00 3f7f 0000 7f00 3f7f 0000 0000 0000 ..?.....?....... > 00000060: ffff ffff ffff 7fbf ff7f ffff 7fbf ff7f ................ > 00000070: ffff ffff ffff ffff ffff ffff ffff ffff ................ > 00000080: ffff ffff ffff ffff ffff ffff ffff ffff ................ > 00000090: ffff ffff ffff ffff ffff ffff ffff ffff ................ > 000000a0: ffff ffff ffff ffff ffff ffff ffff ffff ................ > 000000b0: ffff ffff ffff ffff ffff ffff ffff ffff ................ > ``` > > FYI: > ``` > $ grep processor /proc/cpuinfo |wc -l > 64 > ``` > > Problem seems to be that `ff_sws_slice_worker()` > [libswscale/swscale.c:1222] tries to slice the input to parallelize > the scaling task, in my case in 16 different jobs (gdb'ing the process > shows `nb_threads == nb_jobs == 16`). The 8x8 input is therefore > divided in eight 8x1 slices (1-pixel height), which eventually breaks > in `bayer_to_rgb24_wrapper()` as it asserts `srcSliceH > 1`. The > problem is the same in the 3 Bayer conversion functions > (`bayer_to_rgb24_wrapper()`, `bayer_to_rgb48_wrapper()`, and > `bayer_to_yv12_wrapper()`. > > Wondering about the right solution: We could just enforce `nb_threads > = nb_jobs = 1` for all Bayer inputs. That may be the simplest > solution. Or we could make sure that `nb_threads` (and `nb_jobs`) are > capped at `input_height / 2` (to ensure at least 2 pixels per thread). > > Any suggestions? There already is code that constrains minimum slice size, see dst_slice_align in utils.c. Would extending that code to handle bayer input fix the problem? -- Anton Khirnov _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".