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 D39374A29E for ; Mon, 25 Mar 2024 22:50:21 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id E60D868D5DB; Tue, 26 Mar 2024 00:50:19 +0200 (EET) Received: from relay6-d.mail.gandi.net (relay6-d.mail.gandi.net [217.70.183.198]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id B7CFE68D592 for ; Tue, 26 Mar 2024 00:50:12 +0200 (EET) Received: by mail.gandi.net (Postfix) with ESMTPSA id 16075C0004 for ; Mon, 25 Mar 2024 22:50:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=niedermayer.cc; s=gm1; t=1711407012; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Vj8pZEkdmQ39YT0ssbpqoye2QwruObJ7apDuqi02oNA=; b=BdY6iMn5sjV9yTnaO87K7+zzatjbTHG9JffOUn9qrS4QXcXKF0WSz6mWn7N8cILlwaFt37 POAL9ltD5WUmVhasNL3dBx3xnB5sY2pplFkCUfRbgS3R3A5dXihoaMuBZYYpve1fK/Xf+8 ROAosDWpPC9b3tSQyRI6L2l3wIIr3ScjckMhB8QdJf/w3FT9zzGCO8HeUVqFtWijNpNGPI OMHMrG11opGTxsymell19/Y8P5uXHmqvR+BlT35i81M8YjhaXUmEZ4qkNRQtwRPrA+kwK5 kR7RXIIXJAYvrSKuDmxEU9oIF7u2pU6bC9tZHubUm0rJKpwEZKgLXzshPI/vQw== Date: Mon, 25 Mar 2024 23:50:11 +0100 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20240325225011.GV6420@pb2> References: <20230929232001.23197-1-michael@niedermayer.cc> <47b96a8-db6b-aa20-d48-a6d60f0e84e@passwd.hu> <20230930140403.GK3543730@pb2> <20230930143143.GL3543730@pb2> <169610511838.6638.13529422310033823704@lain.khirnov.net> <20230930222856.GN3543730@pb2> <169623766726.6638.12142285893799599279@lain.khirnov.net> <20231002190333.GV3543730@pb2> <20231003185333.GG3543730@pb2> MIME-Version: 1.0 In-Reply-To: <20231003185333.GG3543730@pb2> X-GND-Sasl: michael@niedermayer.cc Subject: Re: [FFmpeg-devel] [PATCH 1/6] avformat/avidec: support huge durations 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: multipart/mixed; boundary="===============6795498268213012353==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============6795498268213012353== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="pUZ4J5ECQcFz8t0x" Content-Disposition: inline --pUZ4J5ECQcFz8t0x Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Oct 03, 2023 at 08:53:33PM +0200, Michael Niedermayer wrote: > On Tue, Oct 03, 2023 at 11:10:20AM +0200, Tomas H=E4rdin wrote: > > m=E5n 2023-10-02 klockan 21:03 +0200 skrev Michael Niedermayer: > > > On Mon, Oct 02, 2023 at 11:07:47AM +0200, Anton Khirnov wrote: > > > > Quoting Michael Niedermayer (2023-10-01 00:28:56) > > > > > On Sat, Sep 30, 2023 at 10:18:38PM +0200, Anton Khirnov wrote: > > > > > > Quoting Michael Niedermayer (2023-09-30 16:31:43) > > > > > > > On Sat, Sep 30, 2023 at 04:04:03PM +0200, Michael Niedermayer > > > > > > > wrote: > > > > > > > > On Sat, Sep 30, 2023 at 11:35:19AM +0200, Marton Balint > > > > > > > > wrote: > > > > > > > > >=20 > > > > > > > > >=20 > > > > > > > > > On Sat, 30 Sep 2023, Michael Niedermayer wrote: > > > > > > > > >=20 > > > > > > > > > > Fixes: signed integer overflow: 109817402400 * > > > > > > > > > > 301990077 cannot be represented in type 'long long' > > > > > > > > > > Fixes: 51896/clusterfuzz-testcase-minimized- > > > > > > > > > > ffmpeg_dem_AVI_fuzzer-6706191715139584 > > > > > > > > > >=20 > > > > > > > > > > Found-by: continuous fuzzing process > > > > > > > > > > https://github.com/google/oss-fuzz/tree/master/projects= /ffmpeg > > > > > > > > > > Signed-off-by: Michael Niedermayer > > > > > > > > > > > > > > > > > > > > --- > > > > > > > > > > libavformat/avidec.c | 12 ++++++++++-- > > > > > > > > > > 1 file changed, 10 insertions(+), 2 deletions(-) > > > > > > > > > >=20 > > > > > > > > > > diff --git a/libavformat/avidec.c > > > > > > > > > > b/libavformat/avidec.c > > > > > > > > > > index 00bd7a98a9d..cfc693842b7 100644 > > > > > > > > > > --- a/libavformat/avidec.c > > > > > > > > > > +++ b/libavformat/avidec.c > > > > > > > > > > @@ -27,6 +27,7 @@ > > > > > > > > > > #include "libavutil/avstring.h" > > > > > > > > > > #include "libavutil/opt.h" > > > > > > > > > > #include "libavutil/dict.h" > > > > > > > > > > +#include "libavutil/integer.h" > > > > > > > > > > #include "libavutil/internal.h" > > > > > > > > > > #include "libavutil/intreadwrite.h" > > > > > > > > > > #include "libavutil/mathematics.h" > > > > > > > > > > @@ -476,7 +477,7 @@ static int > > > > > > > > > > calculate_bitrate(AVFormatContext *s) > > > > > > > > > > =A0=A0=A0=A0=A0=A0=A0 AVStream *st =3D s->streams[i]; > > > > > > > > > > =A0=A0=A0=A0=A0=A0=A0 FFStream *const sti =3D ffstream(= st); > > > > > > > > > > =A0=A0=A0=A0=A0=A0=A0 int64_t duration; > > > > > > > > > > -=A0=A0=A0=A0=A0=A0=A0 int64_t bitrate; > > > > > > > > > > +=A0=A0=A0=A0=A0=A0=A0 int64_t bitrate =3D 0; > > > > > > > > > >=20 > > > > > > > > > > =A0=A0=A0=A0=A0=A0=A0 for (j =3D 0; j < sti->nb_index_e= ntries; j++) > > > > > > > > > > =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 len +=3D sti->index_e= ntries[j].size; > > > > > > > > > > @@ -484,7 +485,14 @@ static int > > > > > > > > > > calculate_bitrate(AVFormatContext *s) > > > > > > > > > > =A0=A0=A0=A0=A0=A0=A0 if (sti->nb_index_entries < 2 || = st->codecpar- > > > > > > > > > > >bit_rate > 0) > > > > > > > > > > =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 continue; > > > > > > > > > > =A0=A0=A0=A0=A0=A0=A0 duration =3D sti->index_entries[j= -1].timestamp - > > > > > > > > > > sti->index_entries[0].timestamp; > > > > > > > > > > -=A0=A0=A0=A0=A0=A0=A0 bitrate =3D av_rescale(8*len, st= ->time_base.den, > > > > > > > > > > duration * st->time_base.num); > > > > > > > > > > +=A0=A0=A0=A0=A0=A0=A0 if (INT64_MAX / duration >=3D st= ->time_base.num) > > > > > > > > > > { > > > > > > > > > > +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 bitrate =3D av_resca= le(8*len, st- > > > > > > > > > > >time_base.den, duration * st->time_base.num); > > > > > > > > >=20 > > > > > > > > > Why not always use the AVInteger version? This is not > > > > > > > > > performance sensitive > > > > > > > > > as far as I see. > > > > > > > >=20 > > > > > > > > We can, i will have to fix the rounding though so it > > > > > > > > matches av_rescale() > > > > > > >=20 > > > > > > > will apply this with just AVInteger and fixed rounding with > > > > > > > my next push probably > > > > > >=20 > > > > > > This seems MUCH less readable to me. > > > > >=20 > > > > > we can add a av_rescale_2den() > > > >=20 > > > > Won't av_rescale_q(len, (AVRational){8, duration}, st->time_base) > > > > achieve the same effect? > > >=20 > > > duration is 64bit AVRational is 32/32 bit, so i would expect that to > > > not > > > work. > > > If duration was fitting in 32bit then duration * st->time_base.num > > > would not > > > have overflowed > >=20 > > Maybe we need a 64/64-bit version of AVRational.. >=20 > Iam not convinced at this point that we need that. > But its not hard to do, our AVInteger code will do any size integers by j= ust > changing a single number. >=20 > The real annoyance is if you have 32/32 and 64/64 rationals then suddenly > you need many functions to handle both. Sofar only a fuzzed file exceeded > our 64 * 64 / 64 =3D=3D 64 * 32/32 * 32/32 rescale in one place > adding a 64 * 64 / (64 * 64) rescale would fix that one which seems more > limited in spreading complexity through the codebase Ill apply this below, because its undefined behavior and needs to be fixed. If someone has a better solution please replace my code with it. @@ -476,7 +477,7 @@ static int calculate_bitrate(AVFormatContext *s) AVStream *st =3D s->streams[i]; FFStream *const sti =3D ffstream(st); int64_t duration; - int64_t bitrate; + AVInteger bitrate_i, den_i, num_i; for (j =3D 0; j < sti->nb_index_entries; j++) len +=3D sti->index_entries[j].size; @@ -484,9 +485,14 @@ static int calculate_bitrate(AVFormatContext *s) if (sti->nb_index_entries < 2 || st->codecpar->bit_rate > 0) continue; duration =3D sti->index_entries[j-1].timestamp - sti->index_entrie= s[0].timestamp; - bitrate =3D av_rescale(8*len, st->time_base.den, duration * st->ti= me_base.num); - if (bitrate > 0) { - st->codecpar->bit_rate =3D bitrate; + den_i =3D av_mul_i(av_int2i(duration), av_int2i(st->time_base.num)= ); + num_i =3D av_add_i(av_mul_i(av_int2i(8*len), av_int2i(st->time_bas= e.den)), av_shr_i(den_i, 1)); + bitrate_i =3D av_div_i(num_i, den_i); + if (av_cmp_i(bitrate_i, av_int2i(INT64_MAX)) <=3D 0) { + int64_t bitrate =3D av_i2int(bitrate_i); + if (bitrate > 0) { + st->codecpar->bit_rate =3D bitrate; + } } } return 1; [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The bravest are surely those who have the clearest vision of what is before them, glory and danger alike, and yet notwithstanding go out to meet it. -- Thucydides --pUZ4J5ECQcFz8t0x Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEIAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCZgH/oAAKCRBhHseHBAsP q1qhAJ9bPL84W+VTX35q9K3NzKEkdkocbgCfSuoIUdnx3oIjqOrbDHppeE1RdQo= =nYsS -----END PGP SIGNATURE----- --pUZ4J5ECQcFz8t0x-- --===============6795498268213012353== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ 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". --===============6795498268213012353==--