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 E30F649B58 for ; Tue, 2 Apr 2024 21:26:25 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 2CF3F68D05A; Wed, 3 Apr 2024 00:26:18 +0300 (EEST) Received: from srv-infra-2.infra.inf.glb.tvvideoms.com (www.inf.tvvideoms.com [213.205.126.156]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id D3D9468C4F1 for ; Wed, 3 Apr 2024 00:26:11 +0300 (EEST) Received: from cji.paris (unknown [172.16.3.159]) by srv-infra-2.infra.inf.glb.tvvideoms.com (Postfix) with ESMTP id 02D5E40509; Tue, 2 Apr 2024 21:26:10 +0000 (UTC) From: Nicolas Gaullier To: ffmpeg-devel@ffmpeg.org Date: Tue, 2 Apr 2024 23:26:08 +0200 Message-Id: <20240402212609.572420-1-nicolas.gaullier@cji.paris> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH v3 0/1] avformat/demux: fix accurate probing of durations in mpegts/ps 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 Cc: Nicolas Gaullier 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: v3: rebased after ed9363052f4b8b8 applied tonight (add duration_probesize AVOption) Note: I have no other plan for demux/probing; with these two patches, I can cover my use cases, especially mpegts-concats. For remembering, previous cover-letters: v1-------------------- ff_read_packet() is more lightweight, but it leads to important issues when looking for accurate durations. As a side effect, the code looks also simpler with regular av_read_frame() calls. 1)Updates in the fate tests do exhibit most of the results. 2)See also more directly the case of an audio PES containing many frames: >ffprobe tests/data/lavf/lavf.ts -select_streams a -show_entries >stream=duration -of flat Before patch: streams.stream.0.duration="0.757556" After patch: streams.stream.0.duration="1.018778" 3)Here is an additional (commonplace) sample to demonstrate the benefit for twofields-encoded video: https://0x0.st/HFbm.ts (say h264-50i_mp2.ts) >ffprobe h264-50i_mp2.ts -show_entries stream=duration -of flat Before patch: streams.stream.0.duration="2.060000" streams.stream.1.duration="1.176000" After patch: streams.stream.0.duration="2.080000" streams.stream.1.duration="1.200000" v2-------------------- v1: There was an issue with teletext where resolution is set just once at decoder init (teletext resolution is fixed/hard coded), so it is somewhat fragile: when a demuxer context update occurs, it is lost/overriden by avcodec_parameters_to_context(sti->avctx, st->codecpar) in read_frame_internal. They could have been other scenario besides teletext, I don't know. v2: So now at estimate_timings_from_pts, with one or more seeking involved (seeking is detected by the mpegts demuxer and set last_vn=-1, so pmt is forced/updated and results in demuxer context update), it is required to preserve the info in codecpar at first. Thanks to Michael for reporting the issue. Nicolas Gaullier (1): avformat/demux: Fix accurate probing of durations in mpegts/ps libavformat/demux.c | 36 ++-- tests/ref/fate/concat-demuxer-simple2-lavf-ts | 170 +++++++++--------- tests/ref/fate/ts-opus-demux | 4 +- 3 files changed, 100 insertions(+), 110 deletions(-) -- 2.30.2 _______________________________________________ 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".