[FFmpeg-trac] #9943(avformat:new): avformat/mpjpeg: should be more lenient when server fails to produce first boundary

[FFmpeg]

#9943: avformat/mpjpeg: should be more lenient when server fails to produce first
boundary
-------------------------------------+-------------------------------------
             Reporter:  Ratchanan    |                     Type:
  Srirattanamet                      |  enhancement
               Status:  new          |                 Priority:  normal
            Component:  avformat     |                  Version:
                                     |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug: Some old cameras (e.g. D-Link DCS-5020L) produce a
 non-compliant `multipart/x-mixed-replace` stream which doesn't start with
 the boundary. This trips the `mpjpeg` parser with `Invalid data found when
 processing input` error. Since this format is autodetected, it should be
 able to handle this case.

 Specifying `-f mjpeg` works around this issue. However, many library users
 don't allow specifying format directly, thus the workaround can't be
 applied there.

 Attached picture is the first parts of the camera's response, captured
 from Wireshark. I want to just provide you the Wireshark dump, but I would
 have to find a way to redact e.g. my credentials from it.

 Reproducible on ffmpeg 4.4.2 and John Van Sickle's static Linux build
 built on 2022-09-10.

 How to reproduce:
 {{{
 $ ./ffprobe -report -v 9 -loglevel 99 -i http://<redacted>/mjpeg.cgi
 ffprobe started on 2022-09-26 at 14:37:10
 Report written to "ffprobe-20220926-143710.log"
 Log level: 99
 Command line:
 ./ffprobe -report -v 9 -loglevel 99 -i "http://<redacted>/mjpeg.cgi"
 ffprobe version N-63101-gc92edd969a-static
 https://johnvansickle.com/ffmpeg/  Copyright (c) 2007-2022 the FFmpeg
 developers
   built with gcc 8 (Debian 8.3.0-6)
   configuration: --enable-gpl --enable-version3 --enable-static --disable-
 debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio
 --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp
 --enable-libgme --enable-gray --enable-libaom --enable-libfribidi
 --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame
 --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
 --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt
 --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab
 --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264
 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid
 --enable-libzvbi --enable-libzimg
   libavutil      57. 36.101 / 57. 36.101
   libavcodec     59. 42.104 / 59. 42.104
   libavformat    59. 30.101 / 59. 30.101
   libavdevice    59.  8.101 / 59.  8.101
   libavfilter     8. 48.100 /  8. 48.100
   libswscale      6.  8.108 /  6.  8.108
   libswresample   4.  9.100 /  4.  9.100
   libpostproc    56.  7.100 / 56.  7.100
 [NULL @ 0x69644c0] Opening 'http://<redacted>/mjpeg.cgi' for reading
 [http @ 0x6964d00] Setting default whitelist
 'http,https,tls,rtp,tcp,udp,crypto,httpproxy,data'
 [tcp @ 0x6967c00] Original list of addresses:
 [tcp @ 0x6967c00] Address <redacted> port 80
 [tcp @ 0x6967c00] Interleaved list of addresses:
 [tcp @ 0x6967c00] Address <redacted> port 80
 [tcp @ 0x6967c00] Starting connection attempt to <redacted> port 80
 [tcp @ 0x6967c00] Successfully connected to <redacted> port 80
 [http @ 0x6964d00] request: GET /mjpeg.cgi HTTP/1.1
 User-Agent: Lavf/59.30.101
 Accept: */*
 Range: bytes=0-
 Connection: close
 Host: <redacted>
 Icy-MetaData: 1


 [http @ 0x6964d00] header='HTTP/1.0 401 Authorization Required'
 [http @ 0x6964d00] http_code=401
 [http @ 0x6964d00] header='Server: alphapd/2.1.8'
 [http @ 0x6964d00] header='Date: Mon Sep 26 14:37:10 2022'
 [http @ 0x6964d00] header='Pragma: no-cache'
 [http @ 0x6964d00] header='Cache-Control: no-cache'
 [http @ 0x6964d00] header='Content-type: text/html'
 [http @ 0x6964d00] header='Content-length: 103'
 [http @ 0x6964d00] header='WWW-Authenticate: Basic realm="NIPCA"'
 [http @ 0x6964d00] header=''
 [tcp @ 0x6968200] Original list of addresses:
 [tcp @ 0x6968200] Address <redacted> port 80
 [tcp @ 0x6968200] Interleaved list of addresses:
 [tcp @ 0x6968200] Address <redacted> port 80
 [tcp @ 0x6968200] Starting connection attempt to <redacted> port 80
 [tcp @ 0x6968200] Successfully connected to <redacted> port 80
 [http @ 0x6964d00] request: GET /mjpeg.cgi HTTP/1.1
 User-Agent: Lavf/59.30.101
 Accept: */*
 Range: bytes=0-
 Connection: close
 Host: <redacted>
 Icy-MetaData: 1
 Authorization: Basic <redacted>


 [http @ 0x6964d00] header='HTTP/1.0 200 OK'
 [http @ 0x6964d00] http_code=200
 [http @ 0x6964d00] header='Server: alphapd/2.1.8'
 [http @ 0x6964d00] header='Date: Mon Sep 26 14:37:10 2022'
 [http @ 0x6964d00] header='Pragma: no-cache'
 [http @ 0x6964d00] header='Cache-Control: no-cache'
 [http @ 0x6964d00] header='Content-Type: multipart/x-mixed-
 replace;boundary=--video boundary--'
 [http @ 0x6964d00] header=''
 Probing mpjpeg score:0 increased to 75 due to MIME type
 [mpjpeg @ 0x69644c0] Format mpjpeg probed with size=2048 and score=75
 [AVIOContext @ 0x6978780] Statistics: 3000 bytes read, 0 seeks
 http://<redacted>/mjpeg.cgi: Invalid data found when processing input
 }}}
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9943>
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