Recherche avancée

Sur d’autres sites (7175)

• Does ffmpeg rtp_mpegts muxer support setting DVB triplet ?

  19 février 2021, par drake7

  It seems ffmpeg lets you set the DVB triplet with UDP but not with RTP.

  


  FYI : This is a followup on my findings about the rtp_mpegts muxer compared to the mpegts muxer : Question

  


  In my tests I was using ffmpeg version 4.3.1-2021-01-01-full_build-www.gyan.dev on windows.

  


  findings

  


  I analyzed my streams with dectec's "StreamXpert" :

  


  


  • With UDP and it's mpegts muxer, the DVB triplet can be set (1)

    


  


  • With RTP and it's rtp_mpegts muxer, the DVB triplet is ignored (3) (Note that 3a and 3b create very similar results in "StreamXpert".)

    


  


  • Using UDP with DVB triplet as input and output with RTP ignores the DVB triplet (2)

    


  



  


  Interestingly, leaving out the following options...

  


  -pcr_period 20 -pat_period 0.10 -sdt_period 0.25 -metadata:s:a:0 language=nya \
-mpegts_flags +pat_pmt_at_frames -mpegts_flags system_b


  


  ... the rtp_mpegts muxer (3b) creates a valid DVB transport stream, while the the mpegts muxer (4) does not.

  


  ffmpeg params :

  


  



  


  muxer : mpegts (udp)

  


  ffmpeg -f lavfi -i testsrc -r 25 -c:v libx264 -pix_fmt yuv420p -profile:v main -level 3.1 -preset veryfast -vf scale=1280:720,setdar=dar=16/9 -an -bsf:v h264_mp4toannexb -b:v 4M -muxrate 8M \
-pcr_period 20 -pat_period 0.10 -sdt_period 0.25 -metadata:s:a:0 language=nya -mpegts_flags +pat_pmt_at_frames \
-mpegts_transport_stream_id 0x005A \
-mpegts_original_network_id 0x005B \
-mpegts_service_id 0x005C \
-mpegts_pmt_start_pid 0x005D -mpegts_start_pid 0x005E -mpegts_service_type advanced_codec_digital_hdtv \
-metadata service_provider="Provider foo" \
-metadata service_name="Service bar" \
-mpegts_flags system_b -flush_packets 0 \
-f mpegts "udp://239.10.33.10:1234?pkt_size=1316"


  


  



  


  muxer : rtp_mpegts (rtp)

  


  ffmpeg -i "udp://239.10.33.10:1234" -map 0 -c copy \
-f rtp_mpegts "rtp://239.10.33.11:1234?pkt_size=1316"


  


  



  


  a) muxer : rtp_mpegts (rtp)

  


  ffmpeg -f lavfi -i testsrc -r 25 -c:v libx264 -pix_fmt yuv420p -profile:v main -level 3.1 -preset veryfast -vf scale=1280:720,setdar=dar=16/9 -an -bsf:v h264_mp4toannexb -b:v 4M -muxrate 8M \
-pcr_period 20 -pat_period 0.10 -sdt_period 0.25 -metadata:s:a:0 language=nya -mpegts_flags +pat_pmt_at_frames \
-mpegts_transport_stream_id 0x005A \
-mpegts_original_network_id 0x005B \
-mpegts_service_id 0x005C \
-mpegts_pmt_start_pid 0x005D -mpegts_start_pid 0x005E -mpegts_service_type advanced_codec_digital_hdtv \
-metadata service_provider="Provider foo" \
-metadata service_name="Service bar" \
-mpegts_flags system_b -flush_packets 0 \
-f rtp_mpegts "rtp://239.10.33.10:1234?pkt_size=1316"


  


  b) muxer : rtp_mpegts (rtp) (omitting some options)

  


  ffmpeg -f lavfi -i testsrc -r 25 -c:v libx264 -vf scale=1280:720,setdar=dar=16/9 -b:v 4M -muxrate 8M \
-mpegts_transport_stream_id 0x005A \
-mpegts_original_network_id 0x005B \
-mpegts_service_id 0x005C -mpegts_pmt_start_pid 0x005D -mpegts_start_pid 0x005E \
-mpegts_service_type advanced_codec_digital_hdtv \
-metadata service_provider="Provider foo" \
-metadata service_name="Service bar" \
-f rtp_mpegts "rtp://239.10.33.10:1234"


  


  



  


  muxer : mpegts (udp) (omitting some options)

  


  ffmpeg -f lavfi -i testsrc -r 25 -c:v libx264 -vf scale=1280:720,setdar=dar=16/9 -b:v 4M -muxrate 8M \
-mpegts_transport_stream_id 0x005A \
-mpegts_original_network_id 0x005B \
-mpegts_service_id 0x005C -mpegts_pmt_start_pid 0x005D -mpegts_start_pid 0x005E \
-mpegts_service_type advanced_codec_digital_hdtv \
-metadata service_provider="Provider foo" \
-metadata service_name="Service bar" \
-f mpegts "udp://239.10.33.10:1234"


  


  Analyzing the transport stream

  


  

  


• Static ffmpeg library windows

  29 novembre 2022, par peter

  Im trying to use the ffmpeg libraries (libavutil, libswscale, ...) in a bigger project by statically linking them, im not interested in the binaries. Now the issue comes down to getting them statically built. I tried searching for pre-compiled builds but without success.

  


  Following the docs, i compiled them on wsl2 for win64 with

  


  ./configure --arch=x86_64 --target-os=mingw32 --cross-prefix=i686-w64-mingw32- --disable-shared --enable-static
make


  


  After that i copied the libavformat/libavformat.a as libavformat.lib (which should be fine since they are cross-compiled ar archives ?) into my project and linked them with CMake.

  


  When compiling smth like

  


  AVFormatContext* pFormatContext = avformat_alloc_context();


  


  i get a linker error saying

  


  lld-link : error : undefined symbol: avformat_alloc_context


  


  When looking at the libs with dumpbin -linkermember libavformat.lib, i can see

  


  >dumpbin -linkermember libavformat.lib
...
  135CD92 _avformat_alloc_context
...


  


  notice the underscore.

  


  Can i not link the cross-compiled *.a files directly into a windows executable ?

  


  Honestly at this point any ideas are welcome.

  


  Thanks

  


• Playing RTP stream on Android 4.1.2 (Jelly Bean) [closed]

  27 décembre 2024, par Homie_Tomie

  I'll try to keep it quick. Using FFMPEG I started a stream on my PC. Here is the code :

  


  import subprocess

def start_stream():
    command = [
        'ffmpeg',
        '-f', 'gdigrab',  # Desktop capture (Windows)
        '-framerate', '15',  # Low framerate for higher performance
        '-i', 'desktop',  # Capture desktop
        '-c:v', 'libx264',  # Video codec (H.264)
        '-preset', 'ultrafast',  # Ultra-fast encoding preset for minimal latency
        '-tune', 'zerolatency',  # Zero latency for real-time streaming
        '-x264opts', 'keyint=15:min-keyint=15:no-scenecut',  # Frequent keyframes
        '-b:v', '500k',  # Low bitrate to minimize data usage and reduce latency
        '-s', '800x480',  # Resolution fits phone screen and helps performance
        '-max_delay', '0',  # No buffering, instant frame output
        '-flush_packets', '1',  # Flush packets immediately after encoding
        '-f', 'rtp',  # Use mpegts as the container for RTP stream
        'rtp://192.168.72.26:1234',  # Stream over UDP to localhost on port 1234
        '-sdp_file', 'stream.sdp'  # Create SDP file
    ]
    
    try:
        print("Starting stream...")
        subprocess.run(command, check=True)
    except subprocess.CalledProcessError as e:
        print(f"Error occurred: {e}")
    except KeyboardInterrupt:
        print("\nStream interrupted")

if __name__ == "__main__":
    print("Starting screen capture...")
    start_stream()


  


  Now, when I start the stream I can connect to it in VLC when I open up the stream.sdp file. Using the same method I can open up the stream on my iPhone, but when I try to open it on my old Android phone the stream connects but the screen is black. However, when I turn the screen I can see the first frame that was sent to the phone. Why does the stream not work ?

  


  I will be thankful for any and all advice :)