Recherche avancée

Sur d’autres sites (10995)

• Sending video stream from NodeJS to python in real time [closed]

  17 juin 2021, par Tristan Delort

  I'm using a NodeJS server to catch a video stream through a WebRTC PeerConnection and I need to send it to a python script.

  


  I use NodeJS mainly because it's easy to use WebRTC in it and the package 'wrtc' supports RTCVideoSink and python's aiortc doesn't.

  


  I was thinking of using a named pipe with ffmpeg to stream the video stream but 3 questions arose :

  


  


  • Should I use python instead of NodeJS and completely avoid the stream through a named pipe part ? (This means there is a way to extract individual frames from a MediaStreamTrack in python)

    


  


  • If I stick with the "NodeJS - Python" approach, how do I send the stream from one script to the other ? Named pipe ? Unix domain sockets ? And with FFMpeg ?

    


  


  • Finally, for performance purpose I think that sending a stream and not each individual frames is better and simpler but is this true ?

    


  


  


  Thanks all !

  


• FFmpeg outputs video with wrong frame rate when using input pipe

  14 juillet 2020, par Eduardo Lemus

  I am using FFmpeg to convert animated GIF to WEBM video in C#. While this seems to work fine by passing file paths as input/output, my goal is to prevent any access to disk so I'm trying out named pipes instead.

  


  The following options to read the output from a named pipe apparently works fine :

  


  ffmpeg -f image2pipe -i input.gif -c:v libvpx-vp9 -b:v 0 -crf 30 -an -y -f webm \\.\pipe\fromFFmpeg


  


  but when trying to provide also the input from a named pipe, the output WEBM plays at what seems to be the wrong framerate making a 5-6 secs animation to last 2 secs :

  


  ffmpeg -f image2pipe -i \\.\pipe\toFFmpeg -c:v libvpx-vp9 -b:v 0 -crf 30 -an -y -f webm \\.\pipe\fromFFmpeg


  


  Any idea on how to roughly preserve the "same speed" ?

  


• no sound when using ffmpeg and sdl2

  15 octobre 2020, par Nana Noe

  ......
swr_alloc_set_opts(
    audio_convert_ctx, out_channel_layout, AV_SAMPLE_FMT_S16,
    audio_codec_ctx->sample_rate, in_channel_layout,
    audio_codec_ctx->sample_fmt, audio_codec_ctx->sample_rate,
    0, nullptr);
......
len1 = avcodec_decode_audio4(aCodecCtx, &frame, &got_frame, &pkt);
......
SDL_AudioSpec wanted_spec{ audio_codec_ctx->sample_rate,AUDIO_S16SYS,2 }
swr_convert(audio_convert_ctx, &audio_buf_global, frame.nb_samples, (const uint8_t**)frame.data, frame.nb_samples);
......


  


  When i inputed a mp4 file with aac(lc) fltp format,SDL2 was no sound.

  


  But,when i write data in audio_buf_global to a pcm file,SDL2 played the sound.

  


  If set AV_SAMPLE_FMT_S16 to AV_SAMPLE_FMT_FLTP in swr_alloc_set_opts(),SDL2 played sharp vocal.

  


  I thought the sharp vocal which SDL2 played was due to 2x speed,but it was not.When Potplayer played the raw mp4 file with 2x speed,the vocal is clear,not sharp vocal.