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• FFMPEG : Fixing stutter in low-motion areas

  11 juillet 2018, par stevendesu

  I’m trying to create videos with a very specific handful of requirements using FFMPEG :

  • Must have a very low (ideally less than 0.5 seconds) keyframe rate
  • Must have a moderately low ( 1Mbps) bitrate
  • Must run at a reasonable ( 24fps) framerate
  • Must have a width multiple of 4
  • Must not have any B-frames
  • Must be H.264 baseline encoded
  • Must be FLV

  Encoding speed is of no concern. If it takes 2 minutes to encode 1 second of video, that’s absolutely fine. What matters is that the output retains quality at the lowest possible bitrate.

  To this effect I currently have the following FFMPEG command :

  ffmpeg \
  
      -fflags +genpts \
  
      -i big_buck_bunny_1080p_stereo.avi \
  
      -vf "scale=trunc(360*iw/ih/4)*4:360" \
  
      -vf "settb=1/1000" \
  
      -r 24 \
  
      -g 6 \
  
      -keyint_min 6 \
  
      -force_key_frames "expr:gte(t,n_forced/4)"\
  
      -c:v libx264 \
  
          -preset veryslow \
  
          -tune zerolatency \
  
          -profile:v baseline \
  
          -pix_fmt yuv420p \
  
      -b:v 1000k \
  
      -c:a speex \
  
          -ar 16000 \
  
          -ac 1 \
  
      -b:a 64k \
  
      -f flv bbb_lo.flv

  I wish to experiment with various encoding options (me_method, subq, etc) to see how they all affect quality and bitrate. Before that, though, I’ve got an immediate quality issue to address with the command above.

  See the video here on YouTube

  I’ve clipped just a portion of the video that really demonstrates the issue. When an area of the screen undergoes very slight changes in color, there are no motion vectors. This means that certain sections of the video go un-updated until the next keyframe. This can be seen strongly in the tree on the left at the beginning of the video or in the bunny while he’s still asleep. If a viewer were staring at certain regions of the screen it may look like the video is only running at 4 frames per second (my keyframe rate) even though the video is actually running at 24 frames per second — it just isn’t updating the entire screen.

  I’d be okay if these areas of the screen became heavily blurred so long as the motion is preserved. Doing a bit of research I thought that the options -flags2 -fastpskip would fix this, however this option is not working for me :

  [libx264 @ 0x55b63e32c760] [Eval @ 0x7ffea2a7a830] Undefined constant or missing '(' in 'fastpskip'
  
  [libx264 @ 0x55b63e32c760] Unable to parse option value "fastpskip"
  
  [libx264 @ 0x55b63e32c760] Error setting option flags2 to value -fastpskip.

  How can I fix this to preserve motion at the cost of image quality ?

• How do I convert RTSP stream for iOS browser viewing

  27 juin 2018, par humble_coder

  TL ;DR

  I need to convert full RTSP (A/V) stream from Axis IP cameras to be viewed in a fully-contained/not-full-screen div in an iOS browser. Think : "Youtube live stream as viewed from iOS browser". I’ve seen several links that hint at the issue. . .

  • Streaming via RTSP or RTP in HTML5
  • RTSP tunneled HTTP, FFMPEG
  • How can I display an RTSP video stream in a web page ?
  • Embed RTSP Stream into Browser

  . . .but they’re either "incomplete" or out of date.

  The solution must be local and remain behind site firewall (so no external services).

  MORE DETAIL

  I’m currently writing a custom "Axis IP Camera Manager" Vue/Laravel web app for a client. The initial requirements were very simple :

  1. scan network for axis devices and store addresses/info for future use

  2. display grid of MJPEG for selected camera(s).

  The initial requirements were fairly straightforward. Now, though, there are additional requirements :

  3. Record RTSP stream to [seconds] long MP4 streams.

  4. Convert an RTSP stream from AXIS IP CAMERA to something viewable in both desktop and mobile browsers with full A/V.

  I’ve successfully managed #3 by using ffmpeg to capture and store the stream to MP4. However, I’m no video aficionado, and the nature of #4 is still a bit fuzzy to me. Per my understanding I can’t watch RTSP streams in a browser in iOS, but I also can’t stream an "in-process" MP4 over HTTP. I’ve seen references to several items such as Red5, Live555, Wowza, ffserver (discontinued ?), etc. but I’m completely unfamiliar with them. In the short term, I’m looking for a quick "live" conversion solution. In the long term, I’m interested in a deeper understanding of the issue(s) at hand. Any current info/expertise/links/manuals would be appreciated.

• Automatic encoder selection failed for output stream #0:1

  9 juin 2018, par Rafael Lima

  I’m trying to use ffmpeg for edit some videos on android...
  It is working fine but if I try to use drawtext i get error

  the command is :

  path/ffmpeg -y -i /path/asd.mp4 -map 0 -segment_time 15 -f segment -c:v libx264 -preset veryfast -crf 30 -vf "drawtext=text='test message ':fontfile=/path/arial.ttf:box=1:boxborderw=30:boxcolor=0xE86F67@0.7:fix_bounds=true:fontcolor=0x2A363B:fontsize=32:x=0:y=h" -r 30 -force_key_frames expr:gte(t,n_forced*15) -an /path/temp%03d.mp4

  and the error is :

   ffmpeg version 4.0 Copyright (c) 2000-2018 the FFmpeg developers
  
    built with Android (4691093 based on r316199) clang version 6.0.2 (https://android.googlesource.com/toolchain/clang 183abd29fc496f55536e7d904e0abae47888fc7f) (https://android.googlesource.com/toolchain/llvm 34361f192e41ed6e4e8f9aca80a4ea7e9856f327) (based on LLVM 6.0.2svn)
  
   configuration: --prefix=/home/rafa/Desktop/m4/build --target-os=linux --arch=i686 --cpu=i686 --cross-prefix=/home/rafa/Desktop/m4/ndk/toolchain/i686/bin/i686-linux-android- --enable-cross-compile --cc=/home/rafa/Desktop/m4/ndk/toolchain/i686/bin/clang --cxx=/home/rafa/Desktop/m4/ndk/toolchain/i686/bin/clang++ --sysroot=/home/rafa/Desktop/m4/ndk/toolchain/i686/sysroot --pkg-config=/usr/bin/pkg-config --pkg-config-flags=--static --enable-pic --enable-gpl --enable-nonfree --enable-static --disable-shared --enable-ffmpeg --disable-ffplay --disable-ffprobe --disable-doc --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libx264 --enable-libfdk-aac --enable-bsf=aac_adtstoasc --enable-librtmp --enable-zlib --enable-libfreetype --enable-openssl --enable-libfontconfig --disable-asm --disable-devices --extra-cflags=-mno-stackrealign
  
    libavutil      56. 14.100 / 56. 14.100
  
   libavcodec     58. 18.100 / 58. 18.100
  
    libavformat    58. 12.100 / 58. 12.100
  
    libavdevice    58.  3.100 / 58.  3.100
  
       libavfilter     7. 16.100 /  7. 16.100
  
      libswscale      5.  1.100 /  5.  1.100
  
       libswresample   3.  1.100 /  3.  1.100
  
       libpostproc    55.  1.100 / 55.  1.100
  
  
  
  
  
  
  
     major_brand     : isom
  
       minor_version   : 512
  
       compatible_brands: isomiso2avc1mp41
  
       title           : 20180226 174005
  
       artist          : Rafael Lima
  
       date            : 2018
  
       encoder         : Lavf55.49.100
  
       comment         : https://www.youtube.com/watch?v=bkzc9mLyCyo
  
     Duration: 00:03:26.94, start: 0.000000, bitrate: 4156 kb/s
  
       Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 4025 kb/s, 30 fps, 30 tbr, 90k tbn, 60 tbc (default)
  
       Metadata:
  
         handler_name    : VideoHandler
  
       Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
  
       Metadata:
  
         handler_name    : SoundHandler
  
   Automatic encoder selection failed for output stream #0:1. Default encoder for format segment (codec none) is probably disabled. Please choose an encoder manually.
  
   Error selecting an encoder for stream 0:1

  things to considere :
  1. I’ve checked 3 times all the paths are valid
  2. I’ve tested the same command on ffmpeg 4.0 on windows and it works [with the same video]
  3. If I remove the drawtext filter it works fine...

  I tought it ffmpeg was built without drawtext or with some error so i spent 10 days in order to build it bymyself and guarantee every dependency is ok... but at end i got the same error

  does anyone have any idea please

  ==============================
  UPDATE

  I keep testing and if I remove the quotes from the filter and use a text without spacing it works

  ex :
  drawtext=text='test_message':fontfile=/path/arial.ttf:box=1:boxborderw=30:boxcolor=0xE86F67@0.7:fix_bounds=true:fontcolor=0x2A363B:fontsize=32:x=0:y=h

  so I believe there is something related to how android is escapes quotes and simple quotes because i compiled ffmpeg with same parameters and it runs on ubuntu with spaces at the text (just need to use simple quotes)

  does anyone know about it ?