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• swscale/aarch64 : use multiply accumulate and shift-right narrow

  9 décembre 2019, par Sebastian Pop

  swscale/aarch64 : use multiply accumulate and shift-right narrow
  This patch rewrites the innermost loop of ff_yuv2planeX_8_neon to avoid zips and
  
  horizontal adds by using fused multiply adds. The patch also uses ld1r to load
  
  one element and replicate it across all lanes of the vector. The patch also
  
  improves the clipping code by removing the shift right instructions and
  
  performing the shift with the shift-right narrow instructions.
  I see 8% difference on an m6g instance with neoverse-n1 CPUs :
  
  $ ffmpeg -nostats -f lavfi -i testsrc2=4k:d=2 -vf bench=start,scale=1024x1024,bench=stop -f null -
  
  before : t:0.014015 avg:0.014096 max:0.015018 min:0.013971
  
  after :  t:0.012985 avg:0.013013 max:0.013996 min:0.012818
  Tested with `make check` on aarch64-linux.
  Signed-off-by : Sebastian Pop <spop@amazon.com>
  
  Reviewed-by : Clément Bœsch <u@pkh.me>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libswscale/aarch64/output.S

• FFMPEG Incredibly Slow On Windows Server 2016

  1er août 2019, par Ben Gardner

  I have a t2.small (2GB RAM, 1 vCPU) Amazon EC2 instance running a process using FFMPEG. It runs just fine ( 30 fps) on my computer (i7, 12GB RAM), but at around 2 fps on the server. Here’s the command :

  rescale_command = f'ffmpeg -i {srcVideo} -filter_complex \"scale={owidth}:{oheight}, setsar=1:1, pad={dim[0]}:{dim[1]}:{oofx}:{oofy}\" {destVideo}'

  I’ve tried uninstalling and reinstalling ffmpeg/ffprobe

  Edited per llogan’s request, I’ve also discovered that it’s relatively speedy towards the beginning (I’m rescaling 100 times over the course of the program) and slows down towards the end.

  It utilizes 100% of the CPU even from the beginning, though.

  Example command/output :
  ffmpeg -i media/8-1-2019/hi/dl-107.mp4 -filter_complex "scale=607:1080, setsar=1:1, pad=1920:1080:656:0" media/8-1-2019/hi/sl-107.mp4

  ffmpeg version 3.2 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 5.4.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-libebur128 --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-libschroedinger --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-decklink --enable-zlib
  
    libavutil      55. 34.100 / 55. 34.100
  
    libavcodec     57. 64.100 / 57. 64.100
  
    libavformat    57. 56.100 / 57. 56.100
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'media/8-1-2019/hi/dl-107.mp4':
  
    Metadata:
  
      minor_version   : 512
  
      major_brand     : isom
  
      compatible_brands: isomiso2avc1mp41
  
      comment         : vid:v09044ce0000bks3802jqrog167l3rf0
  
      encoder         : Lavf58.20.100
  
    Duration: 00:00:15.12, start: 0.000000, bitrate: 1046 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 540x960 [SAR 1:1 DAR 9:16], 972 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 64 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  [Parsed_setsar_1 @ 00000000023ac840] num:den syntax is deprecated, please use num/den or named options instead
  
  [Parsed_setsar_1 @ 00000000023ad2c0] num:den syntax is deprecated, please use num/den or named options instead
  
  [libx264 @ 00000000023ad800] using SAR=1/1
  
  [libx264 @ 00000000023ad800] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 00000000023ad800] profile High, level 4.0
  
  [libx264 @ 00000000023ad800] 264 - core 148 r2721 72d53ab - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - 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=1 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 'media/8-1-2019/hi/sl-107.mp4':
  
    Metadata:
  
      minor_version   : 512
  
      major_brand     : isom
  
      compatible_brands: isomiso2avc1mp41
  
      comment         : vid:v09044ce0000bks3802jqrog167l3rf0
  
      encoder         : Lavf57.56.100
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc (default)
  
      Metadata:
  
        encoder         : Lavc57.64.100 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
      Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
        encoder         : Lavc57.64.100 aac
  
  Stream mapping:
  
    Stream #0:0 (h264) -> scale (graph 0)
  
    pad (graph 0) -> Stream #0:0 (libx264)
  
    Stream #0:1 -> #0:1 (aac (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame=  453 fps=3.6 q=29.0 Lsize=    3016kB time=00:00:15.01 bitrate=1645.7kbits/s speed=0.12x
  
  video:2763kB audio:237kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.576820%
  
  [libx264 @ 00000000023ad800] frame I:6     Avg QP:20.93  size: 38467
  
  [libx264 @ 00000000023ad800] frame P:118   Avg QP:23.12  size: 11624
  
  [libx264 @ 00000000023ad800] frame B:329   Avg QP:25.19  size:  3725
  
  [libx264 @ 00000000023ad800] consecutive B-frames:  1.8%  2.6%  4.6% 90.9%
  
  [libx264 @ 00000000023ad800] mb I  I16..4: 16.4% 76.7%  6.9%
  
  [libx264 @ 00000000023ad800] mb P  I16..4:  2.3%  5.8%  0.9%  P16..4:  9.8%  3.8%  1.6%  0.0%  0.0%    skip:75.7%
  
  [libx264 @ 00000000023ad800] mb B  I16..4:  0.4%  0.7%  0.1%  B16..8:  9.5%  1.6%  0.3%  direct: 0.6%  skip:86.8%  L0:43.0% L1:50.8% BI: 6.2%
  
  [libx264 @ 00000000023ad800] 8x8 transform intra:67.4% inter:78.3%
  
  [libx264 @ 00000000023ad800] coded y,uvDC,uvAC intra: 32.5% 40.1% 9.4% inter: 2.7% 3.9% 0.1%
  
  [libx264 @ 00000000023ad800] i16 v,h,dc,p: 50% 25%  6% 19%
  
  [libx264 @ 00000000023ad800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 38% 11% 27%  3%  3%  5%  3%  6%  3%
  
  [libx264 @ 00000000023ad800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 43% 11% 12%  5%  7%  9%  4%  7%  3%
  
  [libx264 @ 00000000023ad800] i8c dc,h,v,p: 62% 11% 22%  5%
  
  [libx264 @ 00000000023ad800] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 00000000023ad800] ref P L0: 64.4% 14.3% 16.1%  5.2%
  
  [libx264 @ 00000000023ad800] ref B L0: 90.6%  7.5%  2.0%
  
  [libx264 @ 00000000023ad800] ref B L1: 97.7%  2.3%
  
  [libx264 @ 00000000023ad800] kb/s:1496.84
  
  [aac @ 0000000000628120] Qavg: 754.761

• ffmpeg stream chrome kiosk mode ubuntu 16.04 server

  15 février 2021, par Raul

  I have a weird out-of-sync issue while using ffmpeg to stream to youtube live a chrome browser from an ub untu 16.04 server.

  



  Issue : output video streamed to youtube has audio/video out of sync, sometimes with as much as 3s

  



  Current flow :

  



  1) start pulseaudio - we using something like this to start it :

  



  pulseaudio --start -vvv --disallow-exit --log-target=syslog --high-priority --exit-idle-time=-1 --daemonize


  



  2) start Xvfb

  



  Xvfb :0 -ac -screen 0 1920x1080x24


  



  3) start chrome linux in kiosk mode

  



  google-chrome --kiosk --disable-gpu --incognito --no-first-run --disable-java --disable-plugins --disable-translate --disk-cache-size=$((1024 * 1024)) --disk-cache-dir=/tmp/chrome/ --user-data-dir=/tmp/chrome/ --force-device-scale-factor=1 --window-size=1920,1080 --window-position=0,0 LOCATION_URL


  



  4) start ffmpeg

  



  ffmpeg -y \
  -thread_queue_size 8192 -rtbufsize 250M -f x11grab -video_size 1920x1080 -framerate 24 -i :0 \
  -thread_queue_size 8192 -channel_layout stereo -f alsa -i pulse \
  -c:v libx264 -pix_fmt yuv420p -c:v libx264 -g 48 -crf 24 -filter:v fps=24 -preset ultrafast -tune zerolatency \
  -c:a aac -strict -2 -channel_layout stereo -ab 96k -ac 2 -flags +global_header \
  -f flv YOUTUBE_LIVE_STREAMING_RTMP


  



  Note : this is running on an amazon ec2 instance, meaning there is no soundcard, so alsa and pulseaudio are creating a dummy audio card. However, the latency does not come from there. Logs :

  



  Nov 25 06:14:22 ip-172-31-29-8 pulseaudio[26602]: [pulseaudio] protocol-native.c: Adjust latency mode enabled, configuring sink latency to half of overall latency.
Nov 25 06:14:22 ip-172-31-29-8 pulseaudio[26602]: [pulseaudio] protocol-native.c: Requested latency=23.22 ms, Received latency=23.22 ms
Nov 25 06:14:22 ip-172-31-29-8 pulseaudio[26602]: [pulseaudio] protocol-native.c: Final latency 69.66 ms = 23.22 ms + 2*11.61 ms + 23.22 ms


  



  At this point, here's what we observed :

  



  


  1. if we start ffmpeg exactly after issuing the command to start chrome, we see the DTS errors from ffmpeg. Audio is out of sync with the video and has delay of 3-5seconds AHEAD. We also noticed the out of sync remains the same for the full duration of the stream

  


  2. if we start ffmpeg after around 10seconds, audio and video are almost in sync. We then manually added a -itsoffset -0.125 to the ffmpeg command and everything is perfect.

  


  



  Questions :

  



  

  1. Why would ffmpeg have so much lag if it's started right after chrome ?

  


  2. Is starting the ffmpeg after 10s or X seconds the expected behavior ? That is, is this because the system needs to wait for audio/video signals to be "ready" or something ?

  


  3. Is there a way to 100% calculate or know when Chrome is fully ready and start ffmpeg ? We found sometimes it takes 5s, sometimes 10. Depends on the URL we load.

  


  4. Besides the DTS error that ffmpeg throws, is there any other way to know if audio/video is out-of-sync ? as sometimes we have a delay of between 0.5 to 1s, but ffmpeg does not report anything. And a restart is required to "re-balance" the audio/video inputs and get them back in sync.

  


  5. Can pulseaudio be the problem in this scenario ?

  


  



  Thank you

  



  UPDATE Dec 20

  



  We were able to do some tricks to force chrome to start the audio on page load, and that will force connect to pulseaudio. Doing that, plus adding a 3s delay for ffmpeg to start, there is no more delay when ffmpeg starts.
However, our app is a webRTC app, and we have a STRANGER thing happening : if we start the page with no webcam/audio, once the webcam/audio is enabled, ffmpeg (while showing no errors) has a delay of 2s or so. While keep talking, in about max 30s, that delay is GONE.

  



  So the new questions are :

  



  

  1. Besides the DTS error that ffmpeg throws, is there any other way to know if audio/video is out-of-sync ? as sometimes we have a delay of between 0.5 to 1s, but ffmpeg does not report anything.

  


  2. What could cause the initial audio/video out of sync issue and then catching up ?