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• How to concatenate .mp4 files into one 4x4 movie using -ffmpeg- ?

  7 août 2021, par Clive Nicholas

  How should I best concatenate 16 separate .mp4 files into one 4x4 movie using -ffmpeg- ?

  


  I have workable code to create 2x2 movies (with changeable optional flag calls), with four equally-sized files, thus :

  


  ffmpeg -i foo1.mp4 -i foo2.mp4 -i foo3.mp4 -i foo4.mp4 \ 
 -filter_complex \
   "[0:v][1:v]hstack[t]; \
    [2:v][3:v]hstack[b]; \
    [t][b]vstack,format=yuv420p[v]; \
    [0:a][1:a][2:a][3:a]amerge=inputs=4[a]" \
-map "[v]" \ 
-map "[a]" \
-ac 2 -c:v libx264 \
foo.mp4


  


  and with four unequally-sized files, thus :

  


  ffmpeg -i foo1.mp4 -i foo2.mp4 -i foo3.mp4 -i foo4.mp4 \
 -filter_complex \
   "[0:v]scale=640:360[v0]; \
    [1:v]scale=640:360[v1]; \
    [2:v]scale=640:360[v2]; \
    [3:v]scale=640:360[v3]; \
    [v0][v1]hstack[t]; \
    [v2][v3]hstack[b]; \
    [t][b]vstack,format=yuv420p[v]; \
    [0:a][1:a][2:a][3:a]amerge=inputs=4[a]" \
-map "[v]" \
-map "[a]" \
-c:v libx264 -crf 23 \
-c:a aac -b:a 192k \
foo.mp4


  


  There is a solution posted here for splitting a single movie file into 16 4x4 pieces, but naturally I want to do the opposite ! I can't quite work out in my own mind how I can knit together the necessary elements from my 2x2 code routines and the 4x4 split code into a satisfactory 4x4 solution. It may well be that the 16 individual movie files each have to be re-scaled downwards.

  


  Any ideas would be gratefully received, especially coding solutions which are readily tweakable to any matrix combination (e.g., 3x3, 5x5, etc).

  


  Thanks very much, Clive

  


• avcodec/dvdsubdec, dvbsubdec : remove bitmap dumping in DEBUG builds

  28 mai 2022, par softworkz

  avcodec/dvdsubdec, dvbsubdec : remove bitmap dumping in DEBUG builds
  It's been a regular annoyance and often undesired.
  
  There will be a subtitle filter which allows to dump individual
  
  subtitle bitmaps.
  Signed-off-by : softworkz <softworkz@hotmail.com>
  
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavcodec/dvbsubdec.c
  • [DH] libavcodec/dvdsubdec.c

• Merging input Streams with nodejs/ffmpeg

  14 septembre 2020, par jAndy

  I'm creating a very basic and rudimentary Video-Web-Chat. On the client side, I'm going to use a simple getUserMedia API call to capture the webcam data and send video-data as data-blob to my server.

  


  From There, I'm planning to either use the fluent-ffmpeg library or just spawn ffmpeg myself and pipe that raw data to ffmpeg, which in turn, does some magic and pushes that out as HLS stream to an Amazon AWS Service (for instance), which then gets actually displayed on a Web Browser for all participating people in the video chat.

  


  So far, I think all of this should be fairly easy to implement, but I keep my head spinning around the question, how I can create a "combined" or "merged" frame and stream, so the output HLS data from my server to the distributing cloud service has only to be one combined data stream to receive.

  


  If there are 3 people in that video chat, my server receives 3 data streams from those clients and combines these data streams (from the individual web-cam data sources) into one output stream.

  


  How could that be accomplished ?
Can I "create" a new frame with ffmpeg, so to speak ? I would be very thankful if anybody could give me a heads up here, maybe I'm thinking in a complete wrong direction.

  


  Another question which arises to me is, if I really can just "dump" any data, which I'm receiving from a binary blob created from getUserMedia or MultiStreamRecorder to ffmpeg or if I have to specify somewhere and somehow the exact codecs being used etc.?