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• apng : Add a basic APNG encoder

  31 mars 2015, par Donny Yang

  apng : Add a basic APNG encoder
  Signed-off-by : Donny Yang <work@kota.moe>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] configure
  • [DH] libavcodec/Makefile
  • [DH] libavcodec/allcodecs.c
  • [DH] libavcodec/pngenc.c

• What it the expected behavior when using the input Framerate option (in FFmpeg) when the input is a real-time camera device ?

  28 août 2023, par J.M.

  As far as I know, the use of the Framerate option should be used only on an input files (like sequence of images or perhaps a video file that don't have a defined PTS).

  



  However, if I run the command below on my web-cam, the video still streams fine (at least for a few hours from what I've checked till now). Why is that still works ? Should I expect that something will get wrong ? (maybe later, after a few hours or days of streaming)

  



  ffmpeg -framerate 30 -f v4l2 -copyts -i /dev/video0 -c:v libx264 -r 30 -f mpegts udp://192.168.10.199:1234


  



  EDIT :

  



  After running some more tests, it seems that when I'm running the command like this, the steam get stuck after a few hours :

  



  ffmpeg -framerate 30 -f v4l2 -copyts -i /dev/video0 -c:v libx264 -r 30 -f mpegts udp://192.168.10.199:1234


  



  However, if I run the command like this, it runs for days :

  



  ffmpeg -r 30 -f v4l2 -copyts -i /dev/video0 -c:v libx264 -r 30 -f mpegts udp://192.168.10.199:1234


  



  But I don't understand why...

  


• FFMPEG parameter -sseof position is not “cutting” as expected

  9 mai 2020, par Vitalii

  I have a regular recording of the desktop screen, indefinite in time. I want to keep in memory, only the last 30 seconds. My command looks like this, where I try to cut the video of the last 30 seconds, using -sizeof -30. But the entire length of the video is saved.
  
avfoundation -i '1' it's my macbook screen

  



  ffmpeg -rtbufsize 300M -sseof -30 -f avfoundation -i '1' -c:v libx264 -preset ultrafast -tune zerolatency -crf 25 ~/Desktop/output.mkv


  



  System Macos 10.15
  
ffmpeg version 4.2.2

  



  My full log

  



  ffmpeg -rtbufsize 300M -sseof -30  -f avfoundation -i '1' -c:v libx264 -preset ultrafast -tune zerolatency -crf 25 ~/Desktop/output.mkv
ffmpeg version 4.2.2 Copyright (c) 2000-2019 the FFmpeg developers
  built with Apple clang version 11.0.3 (clang-1103.0.32.59)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.2_3 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags=-fno-stack-check --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
[AVFoundation input device @ 0x7fec8551cec0] Configuration of video device failed, falling back to default.
[avfoundation @ 0x7fec8600a200] Selected pixel format (yuv420p) is not supported by the input device.
[avfoundation @ 0x7fec8600a200] Supported pixel formats:
[avfoundation @ 0x7fec8600a200]   uyvy422
[avfoundation @ 0x7fec8600a200]   yuyv422
[avfoundation @ 0x7fec8600a200]   nv12
[avfoundation @ 0x7fec8600a200]   0rgb
[avfoundation @ 0x7fec8600a200]   bgr0
[avfoundation @ 0x7fec8600a200] Overriding selected pixel format to use uyvy422 instead.
[avfoundation @ 0x7fec8600a200] Stream #0: not enough frames to estimate rate; consider increasing probesize
Cannot use -sseof, duration of 1 not known
Input #0, avfoundation, from '1':
  Duration: N/A, start: 107388.118500, bitrate: N/A
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 2560x1600, 1000k tbr, 1000k tbn, 1000k tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 0x7fec869bee00] MB rate (16000000000) > level limit (16711680)
[libx264 @ 0x7fec869bee00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x7fec869bee00] profile High 4:2:2, level 6.2, 4:2:2 8-bit
[libx264 @ 0x7fec869bee00] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - 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=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=4 lookahead_threads=4 sliced_threads=1 slices=4 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=25.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
Output #0, matroska, to '/Users/vitalii-artec3d/Desktop/output.mkv':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) (H264 / 0x34363248), yuv422p, 2560x1600, q=-1--1, 1000k fps, 1k tbn, 1000k tbc
    Metadata:
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame=  322 fps= 30 q=19.0 Lsize=     947kB time=00:00:10.80 bitrate= 718.0kbits/s speed=0.998x    
video:943kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.382723%
[libx264 @ 0x7fec869bee00] frame I:2     Avg QP:19.00  size:465715
[libx264 @ 0x7fec869bee00] frame P:320   Avg QP:19.30  size:   105
[libx264 @ 0x7fec869bee00] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x7fec869bee00] mb P  I16..4:  0.0%  0.0%  0.0%  P16..4:  0.1%  0.0%  0.0%  0.0%  0.0%    skip:99.9%
[libx264 @ 0x7fec869bee00] coded y,uvDC,uvAC intra: 36.9% 24.9% 21.0% inter: 0.0% 0.1% 0.0%
[libx264 @ 0x7fec869bee00] i16 v,h,dc,p: 66% 28%  4%  2%
[libx264 @ 0x7fec869bee00] i8c dc,h,v,p: 70% 16% 12%  1%
[libx264 @ 0x7fec869bee00] kb/s:23977740.00