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• avcodec/encode : Fix check for encoders impl. encode-simple API

  13 avril 2022, par Andreas Rheinhardt

  avcodec/encode : Fix check for encoders impl. encode-simple API
  FFCodec.cb is a union.
  Reviewed-by : Anton Khirnov <anton@khirnov.net>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/encode.c

• Understanding ffmpeg map option

  7 avril 2021, par Austin Kyker

  I came across the following command in a blog post which creates different quality video streams that are packaged into DASH format via the dash muxer.

  


  ffmpeg -i $VIDEO_IN \
    -preset $PRESET_P -keyint_min $GOP_SIZE -g $GOP_SIZE -sc_threshold 0 \
    -r $FPS -c:v libx264 -pix_fmt yuv420p -c:a aac -b:a 128k -ac 1 -ar 44100 \
    -map v:0 -s:0 $V_SIZE_1 -b:v:0 2M -maxrate:0 2.14M -bufsize:0 3.5M \
    -map v:0 -s:1 $V_SIZE_2 -b:v:1 145k -maxrate:1 155k -bufsize:1 220k \
    -map v:0 -s:2 $V_SIZE_3 -b:v:2 365k -maxrate:2 390k -bufsize:2 640k \
    -map v:0 -s:3 $V_SIZE_4 -b:v:3 730k -maxrate:3 781k -bufsize:3 1278k \
    -map v:0 -s:4 $V_SIZE_4 -b:v:4 1.1M -maxrate:4 1.17M -bufsize:4 2M \
    -map v:0 -s:5 $V_SIZE_5 -b:v:5 3M -maxrate:5 3.21M -bufsize:5 5.5M \
    -map v:0 -s:6 $V_SIZE_5 -b:v:6 4.5M -maxrate:6 4.8M -bufsize:6 8M \
    -map v:0 -s:7 $V_SIZE_6 -b:v:7 6M -maxrate:7 6.42M -bufsize:7 11M \
    -map v:0 -s:8 $V_SIZE_6 -b:v:8 7.8M -maxrate:8 8.3M -bufsize:8 14M \
    -map 0:a \
    -init_seg_name init\$RepresentationID\$.\$ext\$ -media_seg_name chunk\$RepresentationID\$-\$Number%05d\$.\$ext\$ \
    -use_template 1 -use_timeline 1  \
    -seg_duration 4 -adaptation_sets "id=0,streams=v id=1,streams=a" \
    -f dash Dash/dash.mpd


  


  The thing I'm struggling to understand is how the maps work. I've read the Map docs but they don't seem to have a comparable example.

  


  

  1. Why is -map v:0 used for every video stream ?

  


  2. Why does the first map line operate on stream 0 (e.g. -b:v:0) and the next map line operates on stream 1 (e.g. -b:v:1), etc.

  


  


  Would really appreciate a breakdown.

  


• How we compressed videofile (all format) in android programmatically

  29 mars 2017, par prakash choudhary

  i am stuck with the funtionality for the compressed video before upload to the Amazon s3. i am looking functionality like the whatsup that compressed all the video of the gallery and camera after R&D i got FFmpeg library but that is increasing size of the app apk.Please there is any alternative t ? Any idea about this problem