[FFmpeg-trac] #8071(avcodec:new): Integer overflow in bitrate / libx264 encoding

[FFmpeg]

#8071: Integer overflow in bitrate / libx264 encoding
---------------------------------+----------------------------------
             Reporter:  jonfryd  |                     Type:  defect
               Status:  new      |                 Priority:  normal
            Component:  avcodec  |                  Version:  4.1.4
             Keywords:  libx264  |               Blocked By:
             Blocking:           |  Reproduced by developer:  0
Analyzed by developer:  0        |
---------------------------------+----------------------------------
 Summary of the bug:

 There seems to be a 32 bit integer overflow / conversion issue in how the
 video bitrate parameter is being handled by libx264 (I have tested a few
 other encoders and they seem to be fine).

 Notice how a bitrate of 3 gb/s gets interpreted as "-1294967 kb/s" in the
 example below. FFmpeg also displays a warning "The bitrate parameter is
 set too low" which is nice and how I initially detected the problem.

 Bonus info: the same example works fine in version 4.1.

 How to reproduce:
 {{{
 % ffmpeg -f lavfi -i life -c:v libx264 -vb 3G test.mov
 ffmpeg version 4.1.4-0york3~18.04 Copyright (c) 2000-2019 the FFmpeg
 developers
   built with gcc 7 (Ubuntu 7.4.0-1ubuntu1~18.04.1)
   configuration: --prefix=/usr --extra-version='0york3~18.04'
 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu
 --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl
 --disable-stripping --enable-avresample --disable-filter=resample
 --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom
 --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca
 --enable-libcdio --enable-libcodec2 --enable-libflite --enable-
 libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme
 --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa
 --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-
 libpulse --enable-librsvg --enable-librubberband --enable-libshine
 --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh
 --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-
 libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-
 libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi
 --enable-lv2 --enable-omx --enable-openal --enable-opengl --enable-sdl2
 --enable-nonfree --enable-libfdk-aac --enable-libdc1394 --enable-libdrm
 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264
 --enable-shared
   libavutil      56. 22.100 / 56. 22.100
   libavcodec     58. 35.100 / 58. 35.100
   libavformat    58. 20.100 / 58. 20.100
   libavdevice    58.  5.100 / 58.  5.100
   libavfilter     7. 40.101 /  7. 40.101
   libavresample   4.  0.  0 /  4.  0.  0
   libswscale      5.  3.100 /  5.  3.100
   libswresample   3.  3.100 /  3.  3.100
   libpostproc    55.  3.100 / 55.  3.100
 Input #0, lavfi, from 'life':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: rawvideo (B0W1 / 0x31573042), monob, 320x240 [SAR
 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
 Stream mapping:
   Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
 Press [q] to stop, [?] for help
 [swscaler @ 0x556dfb947740] deprecated pixel format used, make sure you
 did set range correctly
 [libx264 @ 0x556dfb936e00] using SAR=1/1
 [libx264 @ 0x556dfb936e00] using cpu capabilities: MMX2 SSE2Fast SSSE3
 SSE4.2 AVX FMA3 BMI2 AVX2
 [libx264 @ 0x556dfb936e00] profile High 4:4:4 Predictive, level 6.2, 4:4:4
 8-bit
 [libx264 @ 0x556dfb936e00] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC
 codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options:
 cabac=1 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1
 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=0
 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=4 threads=7
 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0
 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25
 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=1
 bitrate=2000000 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4
 ip_ratio=1.40 aq=1:1.00
 The bitrate parameter is set too low. It takes bits/s as argument, not
 kbits/s
 Output #0, mov, to 'test.mov':
   Metadata:
     encoder         : Lavf58.20.100
     Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuvj444p(pc),
 320x240 [SAR 1:1 DAR 4:3], q=-1--1, -1294967 kb/s, 25 fps, 12800 tbn, 25
 tbc
     Metadata:
       encoder         : Lavc58.35.100 libx264
     Side data:
       cpb: bitrate max/min/avg: 0/0/-1294967296 buffer size: 0 vbv_delay:
 -1
 frame=  841 fps=575 q=-1.0 Lsize=   16868kB time=00:00:33.52
 bitrate=4122.5kbits/s speed=22.9x
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8071>
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