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• What’s So Hard About Building ?

  10 septembre 2011, par Multimedia Mike — Programming

  I finally had a revelation as to why so building software can be so difficult– because build systems are typically built on programming languages that you don’t normally use in your day to day programming activities. If the project is simple enough, the build system usually takes care of the complexities. If there are subtle complexities — and there always are — then you can to figure out how to customize the build system to meet your needs.

  First, there’s the Makefile. It’s easy to forget that the syntax which comprises a Makefile pretty well qualifies as a programming language. I wonder if it’s Turing-complete ? But writing and maintaining Makefiles manually is arduous and many systems have been created to generate Makefiles for you. At the end of the day, running ‘make’ still requires the presence of a Makefile and in the worst case scenario, you’re going to have to inspect and debug what was automatically generated for that Makefile.

  So there is the widespread GNU build system, a.k.a., “the autotools”, named due to its principle components such as autoconf and automake. In this situation, you have no fewer than 3 distinct languages at work. You write your general build instructions using a set of m4 macros (language #1). These get processed by the autotools in order to generate a shell script (language #2) called configure. When this is executed by the user, it eventually generates a Makefile (language #3).

  Over the years, a few challengers have attempted to dethrone autotools. One is CMake which configures a project using its own custom programming language that you will need to learn. Configuration generates a standard Makefile. So there are 2 languages involved in this approach.

  Another option is SCons, which is Python-based, top to bottom. Only one programming language is involved in the build system ; there’s no Makefile generated and run. Until I started writing this, I was guessing that the Python component generated a Makefile, but no.

  That actually makes SCons look fairly desirable, at least if your only metric when choosing a build system is to minimize friction against rarely-used programming languages.

  I should also make mention of a few others : Apache Ant is a build system in which the build process is described by an XML file. XML doesn’t qualify as a programming language (though that apparently doesn’t stop some people from using it as such). I see there’s also qmake, related to the Qt system. This system uses its own custom syntax.

• How to record RTSP to mp4 10 mins segments directly into FTP server

  31 octobre 2022, par HridyanshNarwal888

  I want to record a tcp RTSP stream in 10mins segments continuously which can be done with ffmpeg but i don't have enough storage on the actual device and i have many space on my FTP server

  


  and i have no idea how to do it i've tried some codes which are recording it perfectly but cant sync to ftp at the same time

  


  here the older code that i'm using

  


  ffmpeg -rtsp_transport tcp -i rtsp://192.168.1.3:10554/tcp/av0_0 -f mp4 -t 60 ftp://my_ftp_url/%Y-%m-%d/%H-%M-%S.mp4  
but it gives the error

  


  [mp4 @ 0x144ae00] muxer does not support non seekable output Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument Error initializing output stream 0:0 --  Conversion failed! exit status 1

  


  If this is not possible in this language or through ffmpeg then I've no problem to change language or packages.

  


  Thanks in advance

  


• FFMPEG subtitle always delay 1 frame

  6 janvier 2019, par lostincomputer2

  I encounter problems encoding video that I ripped from DVD, after ripping the video size is around 300MB and it plays well and subtitle sync well, then I want a smaller size for tablet and encode it using ffmpeg and the result is around 100MB but the subtitle will always late for 1 frame

  # ffmpeg -i "Original.mkv" -level 5.1 -preset veryslow -tune animation -keyint_min 12 -sc_threshold 45 -bf 8 -b_strategy 2 -refs 16 -qmin 10 -qmax 51 -qcomp 0.6 -direct-pred auto -me_range 24 -me_method umh -subq 10 -trellis 2 -an -sn -vcodec libx264 -crf 28.0 output1.mkv
  
  # ffmpeg -i "Original.mkv" -f wav -| neroAacEnc -ignorelength -lc -q 0.4 -if - -of output2.aac
  
  # mkvmerge -o outputFF.mkv --language "0:jpn" --track-name "0:SmallAnime Encode @ CRF 28.0" output1.mkv --no-chapters --language "0:jpn" --track-name "0:2.0 AAC-LC @ 0.4" output2.aac -A -D --language "2:eng" --track-name "2:Styled Subtitle (.ass)" "Original.mkv"

  In aegis sub, the video looks well which the subtitle appear normally, however when played using MPC, the subtitle always late 1 frame

  Aegis show correctly screenshot : http://puu.sh/6N2gy

  Play using MPC problems : http://puu.sh/6N38E.jpg

  Anyone know why this happens ? The ffmpeg uses libx264 video codec and it is configured using bit depth=10. The OS I am using is CentOS 6.4