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• ffmpeg video encoding for mobile devices

  27 janvier 2012, par TimGL

  I'm trying to encode the video file from f4v to mp4 for mobile devices and using 2 different ffmpeg versions with the same configuration files. Encoding goes ok for both files. The one that I convert using ffmpeg version N-32754-g936d4d4-Sherpya failing to play on my blackberry.
  This is the command line that I'm using :

  ffmpeg.exe -i some.avs -vcodec libx264 -b 500k -r 24 -acodec libfaac -ab 128k -ar 48000 -ac 2 -threads 0 -coder 0 -bf 0 -refs 1 -level 30 -maxrate 10000000 -bufsize 10000000 -y test.mp4

  The vido playes ok when I convert it using FFmpeg version SVN-r13712
  Could you give me some light on where the issue couls be ?

• Reduce HLS latency from +30 seconds

  4 juin 2014, par Rick

  Ubuntu 12.04

  nginx 1.2.4

  avconv -version

  avconv version 0.8.10-4:0.8.10-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the Libav developers
  
    built on Feb  6 2014 20:56:59 with gcc 4.6.3
  
  avconv 0.8.10-4:0.8.10-0ubuntu0.12.04.1
  
  libavutil    51. 22. 2 / 51. 22. 2
  
  libavcodec   53. 35. 0 / 53. 35. 0
  
  libavformat  53. 21. 1 / 53. 21. 1
  
  libavdevice  53.  2. 0 / 53.  2. 0
  
  libavfilter   2. 15. 0 /  2. 15. 0
  
  libswscale    2.  1. 0 /  2.  1. 0
  
  libpostproc  52.  0. 0 / 52.  0. 0

  I’m using avconv and nginx to create an HLS stream but right now my latency is regularly well over 30 seconds. After much reading I am aware that HLS has built in latency and that 10s is expected and even preferred but 30s seems quite extreme.

  I’ve seen a lot of discussion on the nginx-rtmp google group, this thread in particular had a lot of suggestions. I have attempted to reduce solve my issue by reducing the hls_fragment and the hls_playlist_length but they haven’t had a significant effect.

  nginx.conf :

  #user  nobody;
  
  worker_processes  1;
  
  
  
  error_log  logs/error.log debug;
  
  
  
  events {
  
      worker_connections  1024;
  
  }
  
  
  
  http {
  
      include       mime.types;
  
      default_type  application/octet-stream;
  
  
  
      sendfile        on;
  
      keepalive_timeout  65;
  
  
  
      server {
  
          listen       8888;
  
          server_name  localhost;
  
  
  
          add_header 'Access-Control-Allow-Origin' "*";
  
  
  
          location /hls {
  
              types {
  
                  application/vnd.apple.mpegurl m3u8;
  
                  video/mp2t ts;
  
              }
  
              root /tmp;
  
          }
  
  
  
          # rtmp stat
  
          location /stat {
  
              rtmp_stat all;
  
              rtmp_stat_stylesheet stat.xsl;
  
          }
  
          location /stat.xsl {
  
              # you can move stat.xsl to a different location
  
              root /usr/build/nginx-rtmp-module;
  
          }
  
  
  
          # rtmp control
  
          location /control {
  
              rtmp_control all;
  
          }
  
  
  
          error_page   500 502 503 504  /50x.html;
  
          location = /50x.html {
  
              root   html;
  
          }
  
      }
  
  }
  
  
  
  rtmp {
  
      server {
  
          listen 1935;
  
          ping 30s;
  
          notify_method get;
  
  
  
          application myapp {
  
              live on;
  
  
  
              hls on;
  
              hls_path /tmp/hls;
  
              hls_base_url http://x.x.x.x:8888/hls/;
  
              hls_sync 2ms;
  
              hls_fragment 2s;
  
  
  
              #hls_variant _low BANDWIDTH=160000;
  
              #hls_variant _mid BANDWIDTH=320000;
  
              #hls_variant _hi BANDWIDTH=640000;
  
          }
  
      }
  
  }

  avconv command :

  avconv -r 30 -y -f image2pipe -codec:v mjpeg -i - -f flv -codec:v libx264 -profile:v baseline -preset ultrafast -tune zerolatency -an -f flv rtmp://127.0.0.1:1935/myapp/mystream

• Setting start date in gource

  5 juin 2014, par rfc1484

  I’m trying to run gource from a certain date, but it reports me a ’codec not found error’.

  This is the command without a start date :

  gource -1280x720 --seconds-per-day 1 --stop-at-end --hide filenames --hide files --git-branch master --camera-mode track --output-ppm-stream - | ffmpeg -y -b 3000k -r 25 -f image2pipe -vcodec ppm -i - test.mp4

  Which works fine and generates the .mp4 file as expected.

  This is the command with a start date :

  gource -1280x720 --start-date '2014-01-01' --seconds-per-day 1 --stop-at-end --hide filenames --hide files --git-branch master --camera-mode track --output-ppm-stream - | ffmpeg -y -b 3000k -r 25 -f image2pipe -vcodec ppm -i - test.mp4

  Which doesn’t work and generates the following error message :

  [image2pipe @ 0x78a600] Could not find codec parameters (Video : ppm)

  Any suggestions on how to fix this ?