From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.ffmpeg.org (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTPS id 7697B4C93C for ; Wed, 6 Aug 2025 16:39:39 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.ffmpeg.org (Postfix) with ESMTP id B60EF68CB3A; Wed, 6 Aug 2025 19:39:34 +0300 (EEST) Received: from 264e01bdf0e5 (code.ffmpeg.org [188.245.149.3]) by ffbox0-bg.ffmpeg.org (Postfix) with ESMTPS id 4302A68C6AA for ; Wed, 6 Aug 2025 19:39:32 +0300 (EEST) MIME-Version: 1.0 From: Park Jeonghwan To: ffmpeg-devel@ffmpeg.org Subject: [FFmpeg-devel] =?utf-8?q?=5BPATCH=5D_=5BPATCH=5D_avformat/apngde?= =?utf-8?q?c=3A_allow_other_chunks_between_fcTL_and_fdAT/IDAT_=28PR_=23201?= =?utf-8?b?NDAp?= 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" Message-Id: <20250806163934.B60EF68CB3A@ffbox0-bg.ffmpeg.org> Date: Wed, 6 Aug 2025 19:39:34 +0300 (EEST) Archived-At: List-Archive: List-Post: PR #20140 opened by Park Jeonghwan (devjeonghwan) URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20140 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20140.patch The APNG demuxer incorrectly assumed that fcTL chunks must be immediately followed by fdAT or IDAT chunks. Per PNG specification section 14.3.2, ancillary chunks may appear in any order relative to other ancillary chunks. This change allows intermediate chunks (like tEXt) between fcTL and frame data chunks, fixing playback of APNG files with metadata. Fixes [#11012](https://trac.ffmpeg.org/ticket/11012). >From f048044c8fe7b1938efc1c3c6d38b56b24e6b62d Mon Sep 17 00:00:00 2001 From: devjeonghwan Date: Thu, 7 Aug 2025 01:37:37 +0900 Subject: [PATCH] avformat/apngdec: allow other chunks between fcTL and fdAT/IDAT --- libavformat/apngdec.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/libavformat/apngdec.c b/libavformat/apngdec.c index d0005046c1..6b9d2c3c88 100644 --- a/libavformat/apngdec.c +++ b/libavformat/apngdec.c @@ -344,14 +344,27 @@ static int apng_read_packet(AVFormatContext *s, AVPacket *pkt) if ((ret = decode_fctl_chunk(s, ctx, pkt)) < 0) return ret; - /* fcTL must precede fdAT or IDAT */ + /* fcTL may be followed by other chunks before fdAT or IDAT */ len = avio_rb32(pb); tag = avio_rl32(pb); - if (len > 0x7fffffff || - tag != MKTAG('f', 'd', 'A', 'T') && - tag != MKTAG('I', 'D', 'A', 'T')) + if (len > 0x7fffffff) return AVERROR_INVALIDDATA; + /* check for empty frame */ + if (tag == MKTAG('f', 'c', 'T', 'L') || + tag == MKTAG('I', 'E', 'N', 'D')) { + size = 38; /* size of fcTL chunk and its header */ + if ((ret = avio_seek(pb, -46, SEEK_CUR)) < 0 || + (ret = av_append_packet(pb, pkt, size)) < 0) + return ret; + + if (ctx->is_key_frame) + pkt->flags |= AV_PKT_FLAG_KEY; + pkt->pts = pkt->dts = AV_NOPTS_VALUE; + pkt->duration = ctx->pkt_duration; + return ret; + } + size = 38 /* fcTL */ + 8 /* len, tag */ + len + 4 /* crc */; if (size > INT_MAX) return AVERROR(EINVAL); -- 2.49.1 _______________________________________________ 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".