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• Ramp- Slow Motion in IOS

  26 juin 2013, par 2vision2

  I have to do "ramp-slow motion" in a video file along with audio, in-between some frames and need to store the ramped video as a new video.

  Ref : http://www.youtube.com/watch?v=BJ3_xMGzauk (watch from 0 to 10s)

  From my analysis, I've found that AVFoundation framework can be helpful.

  Ref :
  http://developer.apple.com/library/ios/#documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/00_Introduction.html

  Copy and pasted from the above link :

  "
  Editing
  AV Foundation uses compositions to create new assets from existing pieces of media (typically, one or more video and audio tracks). You use a mutable composition to add and remove tracks, and adjust their temporal orderings. You can also set the relative volumes and ramping of audio tracks ; and set the opacity, and opacity ramps, of video tracks. A composition is an assemblage of pieces of media held in memory. When you export a composition using an export session, it's collapsed to a file.
  On iOS 4.1 and later, you can also create an asset from media such as sample buffers or still images using an asset writer.

  "

  Questions :
  Can I "ramp-slow mote" the video/audio file using the AVFoundation framework ? Or Is there any other package available ? If i want to handle audio and video separately, please guide me how to do ?

• ffmpeg got stuck while trying to crossfade merge two videos

  30 juin 2017, par Jeflopo

  I’m trying to do a crossfade merge (1s) between two videos. An intro (39secs duration) video with the main video. When I executed the command it started working without throwing errors but at some frame ffmpeg gets stuck.

  I read a lot of q/a here in stackoverflow, and the official docs but I can’t solve this so :

  This is the command :

  ffmpeg -i "inputs/intro.mp4" -i "inputs/240p.mp4" -an -filter_complex \
  
      "[0:v]trim=start=0:end=38,setpts=PTS-STARTPTS[firstclip]; \
  
      [0:v]trim=start=38:end=39,setpts=PTS-STARTPTS[fadeoutsrc]; \
  
      [1:v]trim=start=1,setpts=PTS-STARTPTS[secondclip]; \
  
      [1:v]trim=start=0:end=1,setpts=PTS-STARTPTS[fadeinsrc]; \
  
      [fadeinsrc]format=pix_fmts=yuva420p, fade=t=in:st=0:d=1:alpha=1[fadein]; \
  
      [fadeoutsrc]format=pix_fmts=yuva420p, fade=t=out:st=0:d=1:alpha=1[fadeout]; \
  
      [fadein]fifo[fadeinfifo]; \
  
      [fadeout]fifo[fadeoutfifo]; \
  
      [fadeoutfifo][fadeinfifo]overlay[crossfade]; \
  
      [firstclip][crossfade][secondclip]concat=n=3[output]; \
  
      [0:a][1:a] acrossfade=d=1 [audio]" -vcodec libx264 -map "[output]" -map "[audio]" "outputs/240p.mp4"

  Here’s the raw command (the exact command I used) :

  ffmpeg -i "inputs/intro.mp4" -i "inputs/240p.mp4" -an -filter_complex "[0:v]trim=start=0:end=38,setpts=PTS-STARTPTS[firstclip]; [0:v]trim=start=38:end=39,setpts=PTS-STARTPTS[fadeoutsrc]; [1:v]trim=start=1,setpts=PTS-STARTPTS[secondclip]; [1:v]trim=start=0:end=1,setpts=PTS-STARTPTS[fadeinsrc]; [fadeinsrc]format=pix_fmts=yuva420p, fade=t=in:st=0:d=1:alpha=1[fadein]; [fadeoutsrc]format=pix_fmts=yuva420p, fade=t=out:st=0:d=1:alpha=1[fadeout]; [fadein]fifo[fadeinfifo]; [fadeout]fifo[fadeoutfifo]; [fadeoutfifo][fadeinfifo]overlay[crossfade]; [firstclip][crossfade][secondclip]concat=n=3[output]; [0:a][1:a] acrossfade=d=1 [audio]" -vcodec libx264 -map "[output]" -map "[audio]" "outputs/240p.mp4"

  The "error" is reproducible with and without the -an and the acrossfade filters.

  This is the output :

  PS C:\scripts\ffmpeg> ffmpeg -i "inputs/intro.mp4" -i "inputs/240p.mp4" -an -filter_complex "[0:v]trim=start=0:end=38,setpts=PTS-STARTPTS[firstclip]; [0:v]trim=start=38:end=39,setpts=PTS-STARTPTS[fadeoutsrc]; [1:v]trim=start=1,setpts=PTS-STARTPTS[secondclip]; [1:v]trim=start=0:end=1,setpts=PTS-STARTPTS[fadeinsrc]; [fadeinsrc]format=pix_fmts=yuva420p, fade=t=in:st=0:d=1:alpha=1[fadein]; [fadeoutsrc]format=pix_fmts=yuva420p, fade=t=out:st=0:d=1:alpha=1[fadeout]; [fadein]fifo[fadeinfifo]; [fadeout]fifo[fadeoutfifo]; [fadeoutfifo][fadeinfifo]overlay[crossfade]; [firstclip][crossfade][secondclip]concat=n=3[output]; [0:a][1:a] acrossfade=d=1 [audio]" -map "[output]" -map "[audio]" "outputs/240p.mp4"
  
  ffmpeg version N-86669-gc1d1274 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 7.1.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  
    libavutil      55. 67.100 / 55. 67.100
  
    libavcodec     57.100.102 / 57.100.102
  
    libavformat    57. 75.100 / 57. 75.100
  
    libavdevice    57.  7.100 / 57.  7.100
  
    libavfilter     6. 94.100 /  6. 94.100
  
    libswscale      4.  7.101 /  4.  7.101
  
    libswresample   2.  8.100 /  2.  8.100
  
    libpostproc    54.  6.100 / 54.  6.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'inputs/intro.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.72.101
  
    Duration: 00:06:24.45, start: 0.000000, bitrate: 491 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 426x240 [SAR 1:1 DAR 71:40], 353 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 130 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'inputs/240p.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf56.40.101
  
    Duration: 00:06:24.43, start: 0.000000, bitrate: 375 kb/s
  
      Stream #1:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 426x240 [SAR 1:1 DAR 71:40], 243 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  Stream mapping:
  
    Stream #0:0 (h264) -> trim
  
    Stream #0:0 (h264) -> trim
  
    Stream #0:1 (aac) -> acrossfade:crossfade0
  
    Stream #1:0 (h264) -> trim
  
    Stream #1:0 (h264) -> trim
  
    Stream #1:1 (aac) -> acrossfade:crossfade1
  
    concat -> Stream #0:0 (libx264)
  
    acrossfade -> Stream #0:1 (aac)
  
  Press [q] to stop, [?] for help
  
  [libx264 @ 00000000026b2240] using SAR=1/1
  
  [libx264 @ 00000000026b2240] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
  
  [libx264 @ 00000000026b2240] profile High, level 2.1
  
  [libx264 @ 00000000026b2240] 264 - core 152 r2851 ba24899 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 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=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'outputs/240p.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.75.100
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 426x240 [SAR 1:1 DAR 71:40], q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
  
      Metadata:
  
        encoder         : Lavc57.100.102 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
      Stream #0:1: Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        encoder         : Lavc57.100.102 aac
  
  frame=10369 fps=503 q=28.0 size=   24064kB time=00:06:55.68 bitrate= 474.2kbits/s speed=20.2x

  At frame 10000 it gets stuck... I waited for 1hour but it keeps stuck.

  I’ve updated ffmpeg :

  ffmpeg -version
  
  ffmpeg version N-86669-gc1d1274 Copyright (c) 2000-2017 the FFmpeg developers
  
  built with gcc 7.1.0 (GCC)
  
  configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  
  libavutil      55. 67.100 / 55. 67.100
  
  libavcodec     57.100.102 / 57.100.102
  
  libavformat    57. 75.100 / 57. 75.100
  
  libavdevice    57.  7.100 / 57.  7.100
  
  libavfilter     6. 94.100 /  6. 94.100
  
  libswscale      4.  7.101 /  4.  7.101
  
  libswresample   2.  8.100 /  2.  8.100
  
  libpostproc    54.  6.100 / 54.  6.100

  I used these references :

  • https://www.youtube.com/watch?v=INiRu2_XdJE
  • How to use FFMPEG for a cutaway with audio crossfade ?
  • https://superuser.com/questions/778762/crossfade-between-2-videos-using-ffmpeg
  • https://ffmpeg.org/ffmpeg-filters.html#trim
  • https://ffmpeg.org/ffmpeg.html

• FFMpeg concat streams

  9 juillet 2017, par chourizo

  I am trying to receive two H264 UDP streams from two cameras, and save them to one file (so they are always synchronized). I tried a lot of things, but it always says that there is no video on the second stream (although I can watch it).

  ffmpeg -probesize 20M -analyzeduration 20M -i udp://@127.0.0.1:1234 -probesize 20M -analyzeduration 20M -i udp://@127.0.0.1:1235 -filter_complex "[0:v]fps=15,scale=320:240,setsar=1/1,setpts=PTS-STARTPTS[v0]; [1:v]fps=15,scale=320:240,setsar=1/1,setpts=PTS-STARTPTS[v1]; [v0][v1]concat=n=2:v=1:a=0 [v0] [v1]" -map "[v0]" -map "[v1]" -threads 0 -y kk.ts

  Is it possible to apply the concat to real time streams, so we have a video with two programs as a result ?