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• Save and re-stream RSTP video as straight UDP

  30 septembre 2013, par user1701362

  I am trying to write a program that will connect to a RTSP video source and redirect the video data to another location using UDP. I am also saving the RTSP packets to be able to replay the video stream at a latter moment in time as well. Right now my program can connect to the RTSP video stream and redirect and save, but when I try to look at the redirected video I get nothing using VLC.

  Currently the program just strips out the datagram from the RTSP video packets it receives in its open UDP socket and re-sends them using this code using the boost asio library.

  newVideoSocket->send_to(&dg.data[0], dg.data.size() ,Endpoint);

  When I look at the traffic using Wireshark I see that it is actually sending the data to the new address and it is recognized as a UDP packet, but when I try and view the video using VLC nothing happens. The video stream is Mpeg4 with the video encoded as H.264 and VLC can play it.

  I have tried to connect to the redirected stream as UDP and as RTP at both multicast and unicast addresses but have had no success. Do I need to add or take something out of the datagram before I resend it ? Or is it something wrong with how I am tring to view it in VLC ? Thanks for the help.

• 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

  


• Loop movie and mix with audio by ffmpeg

  29 novembre 2020, par whitebear

  I have a movie file and an audio file with different length.

  


  Audio file is longer than video file.

  


  I want to loop video and mix with audio, then set length same as audio file.

  


  ffmpeg -i "Pentagon_VJ_background_loop.mp4" -stream_loop -1 -t 60 -i "Out1.wav"  -map 0:0 -map 1:0 output.mp4


  


  With this I have -stream_loop -1 but movie doesn't loop. and have no way to set the length to audio file(I use -t 60 instead).

  


  Does anyone help ??