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 E4DE441252 for ; Wed, 11 Jan 2023 07:00:07 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 1C88068B984; Wed, 11 Jan 2023 09:00:04 +0200 (EET) Received: from mout-p-101.mailbox.org (mout-p-101.mailbox.org [80.241.56.151]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id D961C68A318 for ; Wed, 11 Jan 2023 08:59:56 +0200 (EET) Received: from smtp202.mailbox.org (smtp202.mailbox.org [IPv6:2001:67c:2050:b231:465::202]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-101.mailbox.org (Postfix) with ESMTPS id 4NsJTP5sbLz9sm0 for ; Wed, 11 Jan 2023 07:59:53 +0100 (CET) Message-ID: <6dc75a11-014b-b72e-135a-b802d2575f52@gyani.pro> Date: Wed, 11 Jan 2023 12:29:40 +0530 MIME-Version: 1.0 To: ffmpeg-devel@ffmpeg.org References: <20230103102217.1074-1-ffmpeg@gyani.pro> <20230110201018.GA1949656@pb2> Content-Language: en-US From: Gyan Doshi In-Reply-To: <20230110201018.GA1949656@pb2> X-Rspamd-Queue-Id: 4NsJTP5sbLz9sm0 Subject: Re: [FFmpeg-devel] [PATCH] ffmpeg: apply discontinuity adjustment per-stream 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On 2023-01-11 01:40 am, Michael Niedermayer wrote: > On Tue, Jan 03, 2023 at 03:52:17PM +0530, Gyan Doshi wrote: >> At present, the offset for discontinuity adjustment is applied per-file but >> the check for discontinuity is intra-stream so the same discontinuity when >> seen in multiple streams with copyts, leads to compounded adjustment of the >> discontinuity offset. This introduces gaps in streams, leading to loss of sync >> or even de facto loss of stream. >> >> The ts_offset_discont parameter is transferred to InputStream and adjusted >> based on intra-stream gaps. >> --- >> Here's a simulated example to demonstrate the issue: >> 1) generate input >> ffmpeg -f lavfi -i nullsrc=s=32x32:r=1,format=gray -f lavfi -i anullsrc=cl=mono:r=8000 -c:v libx264 -preset superfast -bf 0 -crf 50 -c:a aac -b:a 64k -muxpreload 0 -muxdelay 0 -output_ts_offset 95000 -t 100000 src-100000s.ts >> >> 2) demo >> ffmpeg -copyts -i "src-100000.ts" -vf "showinfo=checksum=0" -af "ashowinfo" -f null - -report >> >> ==Before patch== >> >> timestamp discontinuity for stream #0:1 (id=257, type=audio): -95443717689, new offset= 95443717689 >> timestamp discontinuity for stream #0:0 (id=256, type=video): -95443717689, new offset= 190887435378 >> >> [Parsed_ashowinfo_0 @ 000002700af98800] n:0 pts:759998976 pts_time:94999.9 >> [Parsed_ashowinfo_0 @ 000002700af98800] n:1 pts:760000000 pts_time:95000 >> ... >> [Parsed_ashowinfo_0 @ 000002700af98800] n:745202 pts:1523085824 pts_time:190386 >> [Parsed_ashowinfo_0 @ 000002700af98800] n:745203 pts:1523086848 pts_time:190386 >> [Parsed_ashowinfo_0 @ 000002700af98800] n:745204 pts:2286637614 pts_time:285830 >> [Parsed_ashowinfo_0 @ 000002700af98800] n:745205 pts:2286638638 pts_time:285830 >> >> >> [Parsed_showinfo_0 @ 000002700ec34700] n: 0 pts:8550000000 pts_time:95000 >> [Parsed_showinfo_0 @ 000002700ec34700] n: 1 pts:8550090000 pts_time:95001 >> ... >> [Parsed_showinfo_0 @ 000002700ec34700] n:95380 pts:17134200000 pts_time:190380 >> [Parsed_showinfo_0 @ 000002700ec34700] n:95381 pts:17134290000 pts_time:190381 >> [Parsed_showinfo_0 @ 000002700ec34700] n:95382 pts:25724314592 pts_time:285826 >> [Parsed_showinfo_0 @ 000002700ec34700] n:95383 pts:25724404592 pts_time:285827 >> >> ==After patch== >> >> timestamp discontinuity for stream #0:1 (id=257, type=audio): -95443717689, new stream offset= 95443717689 >> timestamp discontinuity for stream #0:0 (id=256, type=video): -95443717689, new stream offset= 95443717689 >> >> [Parsed_ashowinfo_0 @ 0000023c773c8880] n:0 pts:759998976 pts_time:94999.9 >> [Parsed_ashowinfo_0 @ 0000023c773c8880] n:1 pts:760000000 pts_time:95000 >> ... >> [Parsed_ashowinfo_0 @ 0000023c773c8880] n:745202 pts:1523085824 pts_time:190386 >> [Parsed_ashowinfo_0 @ 0000023c773c8880] n:745203 pts:1523086848 pts_time:190386 >> [Parsed_ashowinfo_0 @ 0000023c773c8880] n:745204 pts:1523087872 pts_time:190386 >> [Parsed_ashowinfo_0 @ 0000023c773c8880] n:745205 pts:1523088896 pts_time:190386 >> >> >> [Parsed_showinfo_0 @ 0000023c795d07c0] n: 0 pts:8550000000 pts_time:95000 >> [Parsed_showinfo_0 @ 0000023c795d07c0] n: 1 pts:8550090000 pts_time:95001 >> ... >> [Parsed_showinfo_0 @ 0000023c795d07c0] n:95380 pts:17134200000 pts_time:190380 >> [Parsed_showinfo_0 @ 0000023c795d07c0] n:95381 pts:17134290000 pts_time:190381 >> [Parsed_showinfo_0 @ 0000023c795d07c0] n:95382 pts:17134380000 pts_time:190382 >> [Parsed_showinfo_0 @ 0000023c795d07c0] n:95383 pts:17134470000 pts_time:190383 >> >> >> >> fftools/ffmpeg.c | 12 ++++++------ >> fftools/ffmpeg.h | 8 ++++---- >> 2 files changed, 10 insertions(+), 10 deletions(-) > I havent looked into this but i have a slightly ungood feeling about this > change Yes, this is a hack. Ideal is to track and sync discontinuities at both file and stream level to avoid compound adjustments. Let me rework this. Regards, Gyan _______________________________________________ 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".