From patchwork Sun Dec 26 16:00:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gyan Doshi X-Patchwork-Id: 32919 Delivered-To: ffmpegpatchwork2@gmail.com Received: by 2002:a6b:cd86:0:0:0:0:0 with SMTP id d128csp9638132iog; Sun, 26 Dec 2021 08:01:19 -0800 (PST) X-Google-Smtp-Source: ABdhPJyQz7G280+JtJ23p5IWvjoB7DPkHciTubi0uERqAFM8t1jcdIwBLV8a1Zbr8RV1KAknl+x5 X-Received: by 2002:a17:907:94c9:: with SMTP id dn9mr12027551ejc.298.1640534479679; Sun, 26 Dec 2021 08:01:19 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1640534479; cv=none; d=google.com; s=arc-20160816; b=kGZG1ZWq9f+RFAprlmg06vHWy4ud5O/FW1QDg/U7NVRpAN5Zz15fDiL4qINpTzw6iS bjaeZC+wz3B6G8a8fiMX8Yb5gSobUHDI75/TBRCXvu+O4rVFUT3Nof+NHfu8cV0GwuMJ CGdH/NaUeI1MRnlauny5wi5Bs0AwZmRqBN7dP4hvdfsAoLq1NUw053brpdAjUPqqvjQW mf4sdNoRG/5HTXW2w1QhCVWID2kHJrEH0IrqR4mMa7F2BVQP/1kSW+V6Z5w+r5cGiMB0 y1A91oprwbmlqRzFzd1NBReqI/Yup/wQp5mTyDI6FtgcR5BHJGuoqY4ajwvZV+pnruWx 0OQw== 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=/RB5W5Zy7+ZRaqnC0fzs12PPWalofVndsVp5K5UlRM8=; b=bwL+dUiZLMjxdAGRjGH9B2WLnLa9cJmVfqBLx1YXPNY4d2Xqb55bn8h2u420bDbuW5 264xfOy2MRTlM5ecUIxRJiypOQmrRTQGCWkiCNUsWQmU8NbTSCdDmcgNlkVzYJmI4suw fO22MZcLL8tPLsp33MOJesWo12BwM86qpPtDQcOxucUOWITAg58RrxEwBbjG+tFylbxb 1S5jDy1afaBmWeToD4JMWo/I7sUX6pmM81mBooXTWAmgjdLirNgU0nthR+Q8dSFe5FG6 J0Vv4uVSifoE4DytfEQiSOd3X3PevBkm9jM4Hpmgfo/VI4kkGmJV/wyyT8oN7d3/i5vB +7Tg== 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 g10si6917994edz.413.2021.12.26.08.01.17; Sun, 26 Dec 2021 08:01:19 -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 8E1A468B110; Sun, 26 Dec 2021 18:01:12 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org 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 3DDC668AFAF for ; Sun, 26 Dec 2021 18:01:06 +0200 (EET) Received: from smtp1.mailbox.org (smtp1.mailbox.org [IPv6:2001:67c:2050:105:465:1:1:0]) (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-101.mailbox.org (Postfix) with ESMTPS id 4JMQWj2027zQk2f for ; Sun, 26 Dec 2021 17:01:05 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de From: Gyan Doshi To: ffmpeg-devel@ffmpeg.org Date: Sun, 26 Dec 2021 21:30:44 +0530 Message-Id: <20211226160044.5913-1-ffmpeg@gyani.pro> MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH v3] 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: XX4z/vT2Y38v 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. --- v3 changes: factored out loop simplified correction logic added doc 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..f93c8bef31 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)/sample_count; + 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 }, };