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 AFF4A450D7 for ; Sat, 7 Jan 2023 04:21:15 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 665B168BD47; Sat, 7 Jan 2023 06:21:12 +0200 (EET) Received: from mout-p-103.mailbox.org (mout-p-103.mailbox.org [80.241.56.161]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id ACB9868B8E0 for ; Sat, 7 Jan 2023 06:21:05 +0200 (EET) Received: from smtp102.mailbox.org (smtp102.mailbox.org [IPv6:2001:67c:2050:b231:465::102]) (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-103.mailbox.org (Postfix) with ESMTPS id 4Npn7z10fmz9sSP for ; Sat, 7 Jan 2023 05:21:03 +0100 (CET) Message-ID: Date: Sat, 7 Jan 2023 09:50:48 +0530 MIME-Version: 1.0 To: ffmpeg-devel@ffmpeg.org References: <20230103102217.1074-1-ffmpeg@gyani.pro> Content-Language: en-US From: Gyan Doshi In-Reply-To: <20230103102217.1074-1-ffmpeg@gyani.pro> X-Rspamd-Queue-Id: 4Npn7z10fmz9sSP 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 2023-01-03 03:52 pm, 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. Comments? > --- > 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(-) > > diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c > index 881d6f0af2..b967055059 100644 > --- a/fftools/ffmpeg.c > +++ b/fftools/ffmpeg.c > @@ -3418,13 +3418,13 @@ static void ts_discontinuity_detect(InputFile *ifile, InputStream *ist, > if (fmt_is_discont) { > if (FFABS(delta) > 1LL * dts_delta_threshold * AV_TIME_BASE || > pkt_dts + AV_TIME_BASE/10 < FFMAX(ist->pts, ist->dts)) { > - ifile->ts_offset_discont -= delta; > + ist->ts_offset_discont -= delta; > av_log(NULL, AV_LOG_DEBUG, > "timestamp discontinuity for stream #%d:%d " > - "(id=%d, type=%s): %"PRId64", new offset= %"PRId64"\n", > + "(id=%d, type=%s): %"PRId64", new stream offset= %"PRId64"\n", > ist->file_index, ist->st->index, ist->st->id, > av_get_media_type_string(ist->par->codec_type), > - delta, ifile->ts_offset_discont); > + delta, ist->ts_offset_discont); > pkt->dts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base); > if (pkt->pts != AV_NOPTS_VALUE) > pkt->pts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base); > @@ -3447,10 +3447,10 @@ static void ts_discontinuity_detect(InputFile *ifile, InputStream *ist, > fmt_is_discont && ifile->last_ts != AV_NOPTS_VALUE) { > int64_t delta = pkt_dts - ifile->last_ts; > if (FFABS(delta) > 1LL * dts_delta_threshold * AV_TIME_BASE) { > - ifile->ts_offset_discont -= delta; > + ist->ts_offset_discont -= delta; > av_log(NULL, AV_LOG_DEBUG, > "Inter stream timestamp discontinuity %"PRId64", new offset= %"PRId64"\n", > - delta, ifile->ts_offset_discont); > + delta, ist->ts_offset_discont); > pkt->dts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base); > if (pkt->pts != AV_NOPTS_VALUE) > pkt->pts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base); > @@ -3463,7 +3463,7 @@ static void ts_discontinuity_detect(InputFile *ifile, InputStream *ist, > static void ts_discontinuity_process(InputFile *ifile, InputStream *ist, > AVPacket *pkt) > { > - int64_t offset = av_rescale_q(ifile->ts_offset_discont, AV_TIME_BASE_Q, > + int64_t offset = av_rescale_q(ist->ts_offset_discont, AV_TIME_BASE_Q, > ist->st->time_base); > > // apply previously-detected timestamp-discontinuity offset > diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h > index 5527dbe49b..d7bba8a190 100644 > --- a/fftools/ffmpeg.h > +++ b/fftools/ffmpeg.h > @@ -352,6 +352,10 @@ typedef struct InputStream { > int64_t next_pts; ///< synthetic pts for the next decode frame (in AV_TIME_BASE units) > int64_t pts; ///< current pts of the decoded frame (in AV_TIME_BASE units) > int wrap_correction_done; > + /** > + * Extra timestamp offset added by discontinuity handling. > + */ > + int64_t ts_offset_discont; > > // the value of AVCodecParserContext.repeat_pict from the AVStream parser > // for the last packet returned from ifile_get_packet() > @@ -444,10 +448,6 @@ typedef struct InputFile { > */ > int64_t start_time_effective; > int64_t ts_offset; > - /** > - * Extra timestamp offset added by discontinuity handling. > - */ > - int64_t ts_offset_discont; > int64_t last_ts; > int64_t start_time; /* user-specified start time in AV_TIME_BASE or AV_NOPTS_VALUE */ > int64_t recording_time; _______________________________________________ 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".