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• Programming Language Levels

  20 mai 2011, par Multimedia Mike — Programming

  I’ve been doing this programming thing for some 20 years now. Things sure do change. One change I ponder from time to time is the matter of programming language levels. Allow me to explain.

  The 1990s
  When I first took computer classes in the early 1990s, my texts would classify computer languages into 3 categories, or levels. The lower the level, the closer to the hardware ; the higher the level, the more abstract (and presumably, easier to use). I recall that the levels went something like this :

  • High level : Pascal, BASIC, Logo, Fortran
  • Medium level : C, Forth
  • Low level : Assembly language

  Keep in mind that these were the same texts which took the time to explain the history of computers from mainframes -> minicomputers -> a relatively recent phenomenon called microcomputers or "PCs".

  Somewhere in the mid-late 1990s, when I was at university, I was introduced to a new tier :

  • Very high level : Perl, shell scripting

  I think there was some debate among my peers about whether C++ and Java were properly classified as high or very high level. The distinction between high and very high, in my observation, seemed to be that very high level languages had more complex data structures (at the very least, a hash / dictionary / associative array / key-value map) built into the language, as well as implicit memory management.

  Modern Day
  These days, the old hierarchy is apparently forgotten (much like minicomputers). I observe that there is generally a much simpler 2-tier classification :

  • Low level : C, assembly language
  • High level : absolutely every other programming language in wide use today

  I find myself wondering where C++ and Objective-C fit in this classification scheme. Then I remember that it doesn’t matter and this is all academic.

  Relevancy
  I think about this because I have pretty much stuck to low-level programming all of my life, mostly due to my interest in game and multimedia-type programming. But the trends in computing have favored many higher level languages and programming paradigms. I woke up one day and realized that the kind of work I often do — lower level stuff — is not very common.

  I’m not here to argue that low or high level is superior. You know I’m all about using the appropriate tool for the job. But I sometimes find myself caught between worlds, having the defend and explain one to the other.

  • On one hand, it’s not unusual for the multitudes of programmers working at the high level to gasp and wonder why I or anyone else would ever use C or assembly language for anything when there are so many beautiful high level languages. I patiently explain that those languages have to be written in some other language (at first) and that they need to run on some operating system and that most assuredly won’t be written in a high level language. For further reading, I refer them to Joel Spolsky’s great essay called Back to Basics which describes why it can be useful to know at least a little bit about how the computer does what it does at the lowest levels.
  • On the other hand, believe it or not, I sometimes have to defend the merits of high level languages to my low level brethren. I’ll often hear variations of, "Any program can be written in C. Using a high level language to achieve the same will create a slow and bloated solution." I try to explain that the trade-off in time to complete the programming task weighed against the often-negligible performance hit of what is often an I/O-bound operation in the first place makes it worthwhile to use the high level language for a wide variety of tasks.

    Or I just ignore them. That’s actually the best strategy.

• FFmpeg - Past Duration Too Large

  14 avril 2018, par Nimble

  I’m having an issue with the warning "Past Duration Too Large" being spammed in my console. There has been quite a bit of discussion about this "warning" online but I have yet to find an actual solution to get rid of it.

  Many just say silence your console, but then I can’t see my segments and other things like warnings, it’s really not a good solution. Another suggests using the fps filter but I have found it creates stutter in the end files...

  Very strangely for reasons completely unknown to me if I double the input framerate and then specify the actual framerate for the output file the warning disappears. Example :

  ffmpeg - y -thread_queue_size 9999 -indexmem 9999 -guess_layout_max 0 -f dshow -video_size 3440x1440 -rtbufsize 2147.48M ^
  
  -framerate 200 -pixel_format nv12 -i video="Video (00 Pro Capture HDMI 4K+)":audio="SPDIF/ADAT (1+2) (RME Fireface UC)" ^
  
  -map 0:0,0:1 -map 0:1 -flags +cgop -force_key_frames expr:gte(t,n_forced*2) -c:v h264_nvenc -preset: llhp -pix_fmt nv12 ^
  
  -b:v 250M -minrate 250M -maxrate 250M -bufsize 250M -c:a aac -ar 44100 -b:a 384k -ac 2 -r 100 ^
  
  -af "atrim=0.038, asetpts=PTS-STARTPTS, aresample=async=250" -vsync 1 -ss 00:00:01.096 -max_muxing_queue_size 9999 ^
  
  -f segment -segment_time 600 -segment_wrap 9 -reset_timestamps 1 C:\Users\djcim\Videos\PC\PC\PC%02d.ts

  As you can see I have -framerate on the input at 200 and -r on the output at 100, believe it or not this gets rid of the warning completely and the resulting file has no issues. However... this is not something you can pull off with any capture card, the only reason I can do this with the Magewell is because under certain resolutions it can record 200fps. Therefore FFmpeg allows me to set it, even though it is double what the card actually allows at the resolution I’m recording. So when I record my camera with a card from Elgato I can’t pull that off :

  ffmpeg -y -thread_queue_size 9999 -indexmem 9999 -guess_layout_max 0 -f dshow -video_size 1920x1080 -rtbufsize 2147.48M ^
  
  -framerate 60 -pixel_format yuyv422 -i video="Game Capture HD60 Pro (Video) (#01)":audio="ADAT (5+6) (RME Fireface UC)" ^
  
  -map 3:0,3:1 -map 3:1 -flags +cgop -r 60 -force_key_frames expr:gte(t,n_forced*2) -c:v h264_nvenc -preset: llhp ^
  
  -pix_fmt yuv420p -b:v 40M -minrate 40M -maxrate 40M -bufsize 40M -c:a aac -ar 44100 -b:a 384k -ac 2 ^
  
  -af "pan=mono|c0=c0, adelay=112|112, aresample=async=250" -vsync 1 -max_muxing_queue_size 9999 -f segment ^
  
  -segment_time 600 -segment_wrap 9 -reset_timestamps 1 C:\Users\djcim\Videos\PC\Camera\CPC%02d.ts 

  When I try to set the -framerate to 120 is just throws an error and wont start recording. Also, while I really wish I could just double the framerate and be done with it, it is pretty clear that that is not a conventional or "actual" solution. That really shouldn’t get rid of the message... The only solution I have come up with besides buying another Magewell is to modify the if statement in the code and compile FFmpeg myself.

  Also I’d like to mention that at times the message is spammed so much that it actually crashes the console, so it’s a real issue not just a warning...

  Any help would be appreciated.

• FFMpeg - Overlay not being shown when enable=between parameter is added

  19 août 2020, par Khawar Raza

  I am using below command to add transitions effect between videos using overlays such that when one videos is about to finish, the overlay gets visible. Before showing overlays, I have to add padding and concatenate videos make one single video and then display overlays. :

  


  ffmpeg 
-i input1.mp4 
-i input2.mp4 
-i input3.mp4 
-i transition1.mp4 
-i transition2.mp4 
-filter_complex 
"[0:v]pad=width=1080:height=1920:x=(1080-iw)*0.5:y=(1920-ih)*0.5:color=black[video0];
[1:v]pad=width=1080:height=1920:x=(1080-iw)*0.5:y=(1920-ih)*0.5:color=black[video1];
[2:v]pad=width=1080:height=1920:x=(1080-iw)*0.5:y=(1920-ih)*0.5:color=black[video2];
[video0][video1][video2]concat=n=3:v=1:a=0[outv];
[3:v]colorkey=0x00d800:0.1[t0];
[t0]scale=w=1080:h=1920[tr0];
[4:v]colorkey=0x00d800:0.1[t1];
[t1]scale=w=1080:h=1920[tr1];
[outv][tr0]overlay=0:0:enable='between(t\,7\,9)'[out0];
[out0][tr1]overlay=0:0:enable='between(t\,12\,15)'[out1];
[0:a][1:a][2:a]concat=n=3:v=0:a=1[audio]" 
-vsync 0 -c:v libx264 -pix_fmt yuv420p -map [out1] -map [audio] -preset ultrafast output.mp4


  


  But above command does not show any overlay video. If I remove enable=between(t, start, end) from overlay parameters, all the overlay gets displayed at video start. I am very beginner to video editing and to FFMpeg. Can anybody guide me what I am doing wrong here ?

  


  Here is the log from console :

  


  ffmpeg version v4.4-dev-416
I/mobile-ffmpeg:  Copyright (c) 2000-2020 the FFmpeg developers
      built with Android (6454773 based on r365631c2) clang version 9.0.8 (https://android.googlesource.com/toolchain/llvm-project 98c855489587874b2a325e7a516b99d838599c6f) (based on LLVM 9.0.8svn)
      configuration: --cross-prefix=aarch64-linux-android- --sysroot=/files/android-sdk/ndk/21.3.6528147/toolchains/llvm/prebuilt/linux-x86_64/sysroot --prefix=/home/taner/Projects/mobile-ffmpeg/prebuilt/android-arm64/ffmpeg --pkg-config=/usr/bin/pkg-config --enable-version3 --arch=aarch64 --cpu=armv8-a --cc=aarch64-linux-android24-clang --cxx=aarch64-linux-android24-clang++ --extra-libs='-L/home/taner/Projects/mobile-ffmpeg/prebuilt/android-arm64/cpu-features/lib -lndk_compat' --target-os=android --enable-neon --enable-asm --enable-inline-asm --enable-cross-compile --enable-pic --enable-jni --enable-optimizations --enable-swscale --enable-shared --enable-v4l2-m2m --disable-outdev=fbdev --disable-indev=fbdev --enable-small --disable-openssl --disable-xmm-clobber-test --disable-debug --enable-lto --disable-neon-clobber-test --disable-programs --disable-postproc --disable-doc --disable-htmlpages --disable-manpages --disable-podpages --disable-txtpages --disable-static --disable-sndio --disable-schannel --disable-securetransport --disable-xlib --disable-cuda --disable-cuvid --disable-nvenc --disable-vaapi --disable-vdpau --disable-videotoolbox --disable-audiotoolbox --disable-appkit --disable-alsa --disable-cuda --disable-cuvid --disable-nvenc --disable-vaapi --disable-vdpau --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-gmp --enable-gnutls --enable-libmp3lame --enable-libass --enable-iconv --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libxml2 --enable-libopencore-amrnb --enable-libshine --enable-libspeex --enable-libwavpack --enable-libkvazaar --enable-libx264 --enable-gpl --enable-libxvid --enable-gpl --enable-libx265 --enable-gpl --enable-libvidstab --enable-gpl --enable-libilbc --enable-libopus --enable-libsnappy --enable-libsoxr --enable-libaom --enable-libtwolame --disable-sdl2 --enable-libvo-amrwbenc --enable-zlib --enable-mediacodec
      libavutil      56. 55.100 / 56. 55.100
      libavcodec     58. 96.100 / 58. 96.100
      libavformat    58. 48.100 / 58. 48.100
      libavdevice    58. 11.101 / 58. 11.101
      libavfilter     7. 87.100 /  7. 87.100
      libswscale      5.  8.100 /  5.  8.100
      libswresample   3.  8.100 /  3.  8.100

I/mobile-ffmpeg: Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input1.mp4':
      Metadata:
        major_brand     : 
    mp42
        minor_version   : 
    0
        compatible_brands: 
    isommp42
        creation_time   : 
    2020-08-12T17:21:49.000000Z
        com.android.version: 
    9
      Duration: 
I/mobile-ffmpeg: 00:00:08.12
    , start: 
    0.000000
    , bitrate: 
    17298 kb/s
        Stream #0:0
    (eng)
    : Video: h264 (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 16309 kb/s
    , SAR 1:1 DAR 16:9
    , 
    28.70 fps, 
    29.50 tbr, 
    90k tbn, 
    60 tbc
     (default)
        Metadata:
          rotate          : 
    90
          creation_time   : 
    2020-08-12T17:21:49.000000Z
          handler_name    : 
    VideoHandle
        Side data:
          
    displaymatrix: rotation of -90.00 degrees
        Stream #0:1
I/mobile-ffmpeg: (eng)
    : Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s
     (default)
        Metadata:
          creation_time   : 
    2020-08-12T17:21:49.000000Z
          handler_name    : 
    SoundHandle
I/mobile-ffmpeg: Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'input2.mp4':
      Metadata:
        major_brand     : 
    isom
        minor_version   : 
    512
        compatible_brands: 
    isomiso2avc1mp41
        encoder         : 
    Lavf57.25.100
I/mobile-ffmpeg:   Duration: 
    00:00:05.97
    , start: 
    0.000000
    , bitrate: 
    770 kb/s
        Stream #1:0
    (und)
    : Audio: aac (mp4a / 0x6134706D), 22050 Hz, stereo, fltp, 128 kb/s
     (default)
        Metadata:
          handler_name    : 
    SoundHandler
        Stream #1:1
    (und)
    : Video: h264 (avc1 / 0x31637661), yuv420p, 368x480, 608 kb/s
    , 
    27.29 fps, 
I/mobile-ffmpeg: 120 tbr, 
    12k tbn, 
    60 tbc
     (default)
        Metadata:
          handler_name    : 
    VideoHandler
I/mobile-ffmpeg: Input #2, mov,mp4,m4a,3gp,3g2,mj2, from 'input3.mp4':
      Metadata:
        major_brand     : 
    isom
        minor_version   : 
    512
        compatible_brands: 
    isomiso2avc1mp41
I/mobile-ffmpeg:     encoder         : 
    Lavf55.19.104
      Duration: 
    00:00:13.05
    , start: 
    0.000000
    , bitrate: 
    2453 kb/s
        Chapter #2:0: 
    start 0.000000, 
    end 13.033000
        Metadata:
          title           : 
        Stream #2:0
    (und)
    : Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s
     (default)
I/mobile-ffmpeg:     Metadata:
          handler_name    : 
    SoundHandler
        Stream #2:1
    (und)
    : Video: h264 (avc1 / 0x31637661), yuv420p, 640x480, 2320 kb/s
    , 
    25 fps, 
    25 tbr, 
    1200k tbn, 
    50 tbc
     (default)
        Metadata:
          handler_name    : 
    VideoHandler
        Stream #2:2
    (eng)
    : Data: bin_data (text / 0x74786574), 0 kb/s
I/mobile-ffmpeg:     Metadata:
          handler_name    : 
    SubtitleHandler
I/mobile-ffmpeg: Input #3, mov,mp4,m4a,3gp,3g2,mj2, from 'transition1.mp4':
      Metadata:
        major_brand     : 
    mp42
        minor_version   : 
    0
I/mobile-ffmpeg:     compatible_brands: 
    mp41isom
        creation_time   : 
    2020-08-17T09:24:04.000000Z
      Duration: 
    00:00:02.22
    , start: 
    0.000000
    , bitrate: 
    2445 kb/s
        Stream #3:0
    (und)
    : Video: h264 (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 2414 kb/s
    , 
    30 fps, 
    30 tbr, 
    30k tbn, 
    60 tbc
     (default)
I/mobile-ffmpeg:     Metadata:
          creation_time   : 
    2020-08-17T09:24:04.000000Z
          handler_name    : 
    VideoHandler
          encoder         : 
    AVC Coding
        Stream #3:1
    (und)
    : Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 79 kb/s
     (default)
        Metadata:
          creation_time   : 
I/mobile-ffmpeg: 2020-08-17T09:24:04.000000Z
          handler_name    : 
I/mobile-ffmpeg: SoundHandler
I/mobile-ffmpeg: Input #4, mov,mp4,m4a,3gp,3g2,mj2, from 'transition2.mp4':
      Metadata:
        major_brand     : 
    mp42
        minor_version   : 
    0
        compatible_brands: 
    mp41isom
        creation_time   : 
    2020-08-17T09:21:33.000000Z
      Duration: 
    00:00:02.22
    , start: 
    0.000000
    , bitrate: 
    2331 kb/s
I/mobile-ffmpeg:     Stream #4:0
    (und)
    : Video: h264 (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 2298 kb/s
    , 
    30 fps, 
    30 tbr, 
    30k tbn, 
    60 tbc
     (default)
        Metadata:
          creation_time   : 
    2020-08-17T09:21:33.000000Z
          handler_name    : 
    VideoHandler
          encoder         : 
    AVC Coding
        Stream #4:1
    (und)
I/mobile-ffmpeg: : Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 79 kb/s
     (default)
        Metadata:
          creation_time   : 
    2020-08-17T09:21:33.000000Z
          handler_name    : 
    SoundHandler
I/mobile-ffmpeg: Stream mapping:
      Stream #0:0 (h264) -> pad
      Stream #0:1 (aac) -> concat:in0:a0
      Stream #1:0 (aac) -> concat:in1:a0
      Stream #1:1 (h264) -> pad
      Stream #2:0 (aac) -> concat:in2:a0
      Stream #2:1 (h264) -> pad
      Stream #3:0 (h264) -> colorkey
      Stream #4:0 (h264) -> colorkey
I/mobile-ffmpeg:   overlay
     -> Stream #0:0 (libx264)
      concat
     -> Stream #0:1 (aac)
    Press [q] to stop, [?] for help
W/mobile-ffmpeg: [graph 0 input from stream 0:0 @ 0x73485c3fc0] sws_param option is deprecated and ignored
    [graph 0 input from stream 1:1 @ 0x73485c4140] sws_param option is deprecated and ignored
    [graph 0 input from stream 2:1 @ 0x73485c4200] sws_param option is deprecated and ignored
    [graph 0 input from stream 3:0 @ 0x73485c42c0] sws_param option is deprecated and ignored
W/mobile-ffmpeg: [graph 0 input from stream 4:0 @ 0x73485c4380] sws_param option is deprecated and ignored
W/mobile-ffmpeg: [swscaler @ 0x7324db9000] No accelerated colorspace conversion found from yuv420p to argb.
W/mobile-ffmpeg: [swscaler @ 0x7324876000] No accelerated colorspace conversion found from yuv420p to argb.
I/mobile-ffmpeg: [libx264 @ 0x7332f9a500] using SAR=1/1
W/mobile-ffmpeg: [libx264 @ 0x7332f9a500] MB rate (8160000000) > level limit (16711680)
I/mobile-ffmpeg: [libx264 @ 0x7332f9a500] using cpu capabilities: ARMv8 NEON
I/mobile-ffmpeg: [libx264 @ 0x7332f9a500] profile Constrained Baseline, level 6.2, 4:2:0, 8-bit
    [libx264 @ 0x7332f9a500] 264 - core 160 - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
I/mobile-ffmpeg: Output #0, mp4, to 'output.mp4':
      Metadata:
I/mobile-ffmpeg:     major_brand     : 
    mp42
        minor_version   : 
    0
        compatible_brands: 
    isommp42
        com.android.version: 
    9
        encoder         : 
    Lavf58.48.100
        Chapter #0:0: 
    start 0.000000, 
    end 13.033000
        Metadata:
          title           : 
        Stream #0:0
I/mobile-ffmpeg: : Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 1080x1920 [SAR 1:1 DAR 9:16], q=-1--1
    , 
    1000k tbn, 
    1000k tbc
     (default)
        Metadata:
          encoder         : 
    Lavc58.96.100 libx264
        Side data:
          
    cpb: 
    bitrate max/min/avg: 0/0/0 buffer size: 0 
    vbv_delay: N/A
        Stream #0:1
    : Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s
     (default)
        Metadata:
I/mobile-ffmpeg:       encoder         : 
    Lavc58.96.100 aac
E/Progress: Progress: 3.6918316
D/mobile-ffmpeg: Progress: frame: 1, time: 1002, Pct: 0.036918
I/mobile-ffmpeg: frame=    1 fps=0.0 q=0.0 size=       0kB time=00:00:01.00 bitrate=   0.5kbits/s speed=1.13x