From patchwork Tue Dec 28 16:42:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gyan Doshi X-Patchwork-Id: 32934 Delivered-To: ffmpegpatchwork2@gmail.com Received: by 2002:a6b:cd86:0:0:0:0:0 with SMTP id d128csp11346807iog; Tue, 28 Dec 2021 08:42:46 -0800 (PST) X-Google-Smtp-Source: ABdhPJzhI0Dcrg6kmST4afnaqSXhKlV+qJ8nHtpyNpD6GUcS1f/XYZ8RkZZh6+M4n0W+pGVY7KTn X-Received: by 2002:a17:906:b84a:: with SMTP id ga10mr17668792ejb.605.1640709766333; Tue, 28 Dec 2021 08:42:46 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1640709766; cv=none; d=google.com; s=arc-20160816; b=ADL6ScDNynRK3JMbAhWqzKnf2HJPlu+exEKz5ewNRlCPb7rNr2VCNyyDLVyKMC8l+N u11+2f57azseW7d/LVBBfsjl4XwvMDpWQARKU244rYTEvPYdRvzd9RP7CfldgNb98Q1A 4PTOqbFFPmm/2VIXsl12lOOwqvrMmllYrBnz8qG3ZiB4MzfFcz5hbaPNmZ/512qI0KVI VrNZvJJPm0JCoqXGLgihBRhf9DFi0yCesG9VdL1DGitIWfi03ixeY6TqycjuhohwgWBz 8SJklE5GCnkXCgXPZjhuKk75WjIgJ3BYPSgiFrRcSlY2aHiXg+O75KrTlbK+88SiZCBE qHUg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:content-transfer-encoding:reply-to:list-subscribe :list-help:list-post:list-archive:list-unsubscribe:list-id :precedence:subject:mime-version:message-id:date:to:from :delivered-to; bh=gKHE789y7E69NZHh39x5Ia1DQQpwtrR6mXAIDKJa6mA=; b=o2j6bBvJEoqCXx1epube0LVBfHDqf2cfs3wVkqm1zHTNRPyn61rNpelvyZzClcx8g2 ZWe8o/aEV7bgdlhr2u1TeZa+0qJu8EnfgxD1TrLIRzZozJIxJitTDZ/4jf3G1deS0ptP rijN+u6va2etQkdQyGO76IeBSZvnaUz3CtsujVY+fdjizkU4mhYJL9xWA38pu5FuqCSh U72fEo8Jf70R73Xv40pQ7HuAn1+GcSDg6JF0R9GFuWXcTKEYuXnS+a2zKwZW20XQqUZi LNxfSGRNXlmTnVT1G1y2lKH4MvUGqzT0z6fD0wvDAkoEt5hU0k7DFFPGCh0VUjcBDDMC YbRw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) smtp.mailfrom=ffmpeg-devel-bounces@ffmpeg.org Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org. [79.124.17.100]) by mx.google.com with ESMTP id dt21si9871843ejc.454.2021.12.28.08.42.45; Tue, 28 Dec 2021 08:42:46 -0800 (PST) Received-SPF: pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) client-ip=79.124.17.100; Authentication-Results: mx.google.com; spf=pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) smtp.mailfrom=ffmpeg-devel-bounces@ffmpeg.org Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 7365468AF86; Tue, 28 Dec 2021 18:42:41 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org 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 C75D368A867 for ; Tue, 28 Dec 2021 18:42:34 +0200 (EET) Received: from smtp102.mailbox.org (smtp102.mailbox.org [IPv6:2001:67c:2050:105:465:1:3:0]) (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 4JNgLd4wPpzQkBn for ; Tue, 28 Dec 2021 17:42:33 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de From: Gyan Doshi To: ffmpeg-devel@ffmpeg.org Date: Tue, 28 Dec 2021 22:12:03 +0530 Message-Id: <20211228164203.617-1-ffmpeg@gyani.pro> MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH v4] avformat/mov: add option max_stts_delta 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 Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" X-TUID: 3eo1dfeInOB2 Very high stts sample deltas may occasionally be intended but usually they are written in error or used to store a negative value for dts correction when treated as signed 32-bit integers. This option lets the user set an upper limit, beyond which the delta is clamped to 1. Values greater than the limit if negative when cast to int32 are used to adjust onward dts. Unit is the track time scale. Default is UINT_MAX - 48000*10 which allows upto a 10 second dts correction for 48 kHz audio streams while accommodating 99.9% of uint32 range. --- v4 change: avoid division by 0 doc/demuxers.texi | 9 ++++++++ libavformat/isom.h | 1 + libavformat/mov.c | 55 +++++++++++++++++++++++++--------------------- 3 files changed, 40 insertions(+), 25 deletions(-) diff --git a/doc/demuxers.texi b/doc/demuxers.texi index cab8a7072c..99d4ab7bc5 100644 --- a/doc/demuxers.texi +++ b/doc/demuxers.texi @@ -713,6 +713,15 @@ specify. @item decryption_key 16-byte key, in hex, to decrypt files encrypted using ISO Common Encryption (CENC/AES-128 CTR; ISO/IEC 23001-7). + +@item max_stts_delta +Very high sample deltas written in a trak's stts box may occasionally be intended but usually they are written in +error or used to store a negative value for dts correction when treated as signed 32-bit integers. This option lets +the user set an upper limit, beyond which the delta is clamped to 1. Values greater than the limit if negative when +cast to int32 are used to adjust onward dts. + +Unit is the track time scale. Range is 0 to UINT_MAX. Default is @code{UINT_MAX - 48000*10} which allows upto +a 10 second dts correction for 48 kHz audio streams while accommodating 99.9% of @code{uint32} range. @end table @subsection Audible AAX diff --git a/libavformat/isom.h b/libavformat/isom.h index ef8f19b18c..625dea8421 100644 --- a/libavformat/isom.h +++ b/libavformat/isom.h @@ -305,6 +305,7 @@ typedef struct MOVContext { int32_t movie_display_matrix[3][3]; ///< display matrix from mvhd int have_read_mfra_size; uint32_t mfra_size; + uint32_t max_stts_delta; } MOVContext; int ff_mp4_read_descr_len(AVIOContext *pb); diff --git a/libavformat/mov.c b/libavformat/mov.c index 2aed6e80ef..351ecde770 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -2925,6 +2925,8 @@ static int mov_read_stts(MOVContext *c, AVIOContext *pb, MOVAtom atom) unsigned int i, entries, alloc_size = 0; int64_t duration = 0; int64_t total_sample_count = 0; + int64_t current_dts = 0; + int64_t corrected_dts = 0; if (c->fc->nb_streams < 1) return 0; @@ -2965,11 +2967,34 @@ static int mov_read_stts(MOVContext *c, AVIOContext *pb, MOVAtom atom) sc->stts_data[i].count= sample_count; sc->stts_data[i].duration= sample_duration; - av_log(c->fc, AV_LOG_TRACE, "sample_count=%d, sample_duration=%d\n", + av_log(c->fc, AV_LOG_TRACE, "sample_count=%u, sample_duration=%u\n", sample_count, sample_duration); - duration+=(int64_t)sample_duration*(uint64_t)sample_count; - total_sample_count+=sample_count; + /* STTS sample offsets are uint32 but some files store it as int32 + * with negative values used to correct DTS delays. + There may be abnormally large values as well. */ + if (sample_duration > c->max_stts_delta) { + // assume high delta is a correction if negative when cast as int32 + int32_t delta_magnitude = (int32_t)sample_duration; + av_log(c->fc, AV_LOG_WARNING, "Too large sample offset %u in stts entry %u with count %u in st:%d. Clipping to 1.\n", + sample_duration, i, sample_count, st->index); + sc->stts_data[i].duration = 1; + corrected_dts += (delta_magnitude < 0 ? (int64_t)delta_magnitude : 1) * sample_count; + } else { + corrected_dts += sample_duration * sample_count; + } + + current_dts += sc->stts_data[i].duration * sample_count; + + if (current_dts > corrected_dts) { + int64_t drift = (current_dts - corrected_dts)/FFMAX(sample_count, 1); + uint32_t correction = (sc->stts_data[i].duration > drift) ? drift : sc->stts_data[i].duration - 1; + current_dts -= correction * sample_count; + sc->stts_data[i].duration -= correction; + } + + duration+=(int64_t)sc->stts_data[i].duration*(uint64_t)sc->stts_data[i].count; + total_sample_count+=sc->stts_data[i].count; } sc->stts_count = i; @@ -3856,13 +3881,10 @@ static void mov_build_index(MOVContext *mov, AVStream *st) unsigned int distance = 0; unsigned int rap_group_index = 0; unsigned int rap_group_sample = 0; - int64_t last_dts = 0; - int64_t dts_correction = 0; int rap_group_present = sc->rap_group_count && sc->rap_group; int key_off = (sc->keyframe_count && sc->keyframes[0] > 0) || (sc->stps_count && sc->stps_data[0] > 0); current_dts -= sc->dts_shift; - last_dts = current_dts; if (!sc->sample_count || sti->nb_index_entries) return; @@ -3973,26 +3995,8 @@ static void mov_build_index(MOVContext *mov, AVStream *st) current_offset += sample_size; stream_size += sample_size; - /* A negative sample duration is invalid based on the spec, - * but some samples need it to correct the DTS. */ - if (sc->stts_data[stts_index].duration < 0) { - av_log(mov->fc, AV_LOG_WARNING, - "Invalid SampleDelta %d in STTS, at %d st:%d\n", - sc->stts_data[stts_index].duration, stts_index, - st->index); - dts_correction += sc->stts_data[stts_index].duration - 1; - sc->stts_data[stts_index].duration = 1; - } current_dts += sc->stts_data[stts_index].duration; - if (!dts_correction || current_dts + dts_correction > last_dts) { - current_dts += dts_correction; - dts_correction = 0; - } else { - /* Avoid creating non-monotonous DTS */ - dts_correction += current_dts - last_dts - 1; - current_dts = last_dts + 1; - } - last_dts = current_dts; + distance++; stts_sample++; current_sample++; @@ -8577,6 +8581,7 @@ static const AVOption mov_options[] = { { "decryption_key", "The media decryption key (hex)", OFFSET(decryption_key), AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_DECODING_PARAM }, { "enable_drefs", "Enable external track support.", OFFSET(enable_drefs), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, FLAGS }, + { "max_stts_delta", "treat offsets above this value as invalid", OFFSET(max_stts_delta), AV_OPT_TYPE_INT, {.i64 = UINT_MAX-48000*10 }, 0, UINT_MAX, .flags = AV_OPT_FLAG_DECODING_PARAM }, { NULL }, };