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• Combine Audio and Images in Stream

  19 décembre 2017, par SenorContento

  I would like to be able to create images on the fly and also create audio on the fly too and be able to combine them together into an rtmp stream (for Twitch or YouTube). The goal is to accomplish this in Python 3 as that is the language my bot is written in. Bonus points for not having to save to disk.

  So far, I have figured out how to stream to rtmp servers using ffmpeg by loading a PNG image and playing it on loop as well as loading a mp3 and then combining them together in the stream. The problem is I have to load at least one of them from file.

  I know I can use Moviepy to create videos, but I cannot figure out whether or not I can stream the video from Moviepy to ffmpeg or directly to rtmp. I think that I have to generate a lot of really short clips and send them, but I want to know if there’s an existing solution.

  There’s also OpenCV which I hear can stream to rtmp, but cannot handle audio.

  A redacted version of an ffmpeg command I have successfully tested with is

  ffmpeg -loop 1 -framerate 15 -i ScreenRover.png -i "Song-Stereo.mp3" -c:v libx264 -preset fast -pix_fmt yuv420p -threads 0 -f flv rtmp://SITE-SUCH-AS-TWITCH/.../STREAM-KEY

  or

  cat Song-Stereo.mp3 | ffmpeg -loop 1 -framerate 15 -i ScreenRover.png -i - -c:v libx264 -preset fast -pix_fmt yuv420p -threads 0 -f flv rtmp://SITE-SUCH-AS-TWITCH/.../STREAM-KEY

  I know these commands are not set up properly for smooth streaming, the result manages to screw up both Twitch’s and Youtube’s player and I will have to figure out how to fix that.

  The problem with this is I don’t think I can stream both the image and the audio at once when creating them on the spot. I have to load one of them from the hard drive. This becomes a problem when trying to react to a command or user chat or anything else that requires live reactions. I also do not want to destroy my hard drive by constantly saving to it.

  As for the python code, what I have tried so far in order to create a video is the following code. This still saves to the HD and is not responsive in realtime, so this is not very useful to me. The video itself is okay, with the one exception that as time passes on, the clock the qr code says versus the video’s clock start to spread apart farther and farther as the video gets closer to the end. I can work around that limitation if it shows up while live streaming.

  def make_frame(t):
  
    img = qrcode.make("Hello! The second is %s!" % t)
  
    return numpy.array(img.convert("RGB"))
  
  
  
  clip = mpy.VideoClip(make_frame, duration=120)
  
  clip.write_gif("test.gif",fps=15)
  
  
  
  gifclip = mpy.VideoFileClip("test.gif")
  
  gifclip.set_duration(120).write_videofile("test.mp4",fps=15)

  My goal is to be able to produce something along the psuedo-code of

  original_video = qrcode_generator("I don't know, a clock, pyotp, today's news sources, just anything that can be generated on the fly!")
  
  original_video.overlay_text(0,0,"This is some sample text, the left two are coordinates, the right three are font, size, and color", Times_New_Roman, 12, Blue)
  
  original_video.add_audio(sine_wave_generator(0,180,2)) # frequency min-max, seconds
  
  
  
  # NOTICE - I did not add any time measurements to the actual video itself. The whole point is this is a live stream and not a video clip, so the time frame would be now. The 2 seconds list above is for our psuedo sine wave generator to know how long the audio clip should be, not for the actual streaming library.
  
  
  
  stream.send_to_rtmp_server(original_video) # Doesn't matter if ffmpeg or some native library

  The above example is what I am looking for in terms of video creation in Python and then streaming. I am not trying to create a clip and then stream it later, I am trying to have the program be able to respond to outside events and then update it’s stream to do whatever it wants. It is sort of like a chat bot, but with video instead of text.

  def track_movement(...):
  
    ...
  
    return ...
  
  
  
  original_video = user_submitted_clip(chat.lastVideoMessage)
  
  original_video.overlay_text(0,0,"The robot watches the user's movements and puts a blue square around it.", Times_New_Roman, 12, Blue)
  
  original_video.add_audio(sine_wave_generator(0,180,2)) # frequency min-max, seconds
  
  
  
  # It would be awesome if I could also figure out how to perform advance actions such as tracking movements or pulling a face out of a clip and then applying effects to it on the fly. I know OpenCV can track movements and I hear that it can work with streams, but I cannot figure out how that works. Any help would be appreciated! Thanks!

  Because I forgot to add the imports, here are some useful imports I have in my file !

  import pyotp
  
  import qrcode
  
  from io import BytesIO
  
  from moviepy import editor as mpy

  The library, pyotp, is for generating one time pad authenticator codes, qrcode is for the qr codes, BytesIO is used for virtual files, and moviepy is what I used to generate the GIF and MP4. I believe BytesIO might be useful for piping data to the streaming service, but how that happens, depends entirely on how data is sent to the service, whether it be ffmpeg over command line (from subprocess import Popen, PIPE) or it be a native library.

• Segmentation fault in samplerate conversion function

  17 juin 2014, par user3749290

  playmp3() using libmpg123

  if (isPaused==0 && mpg123_read(mh, buffer, buffer_size, &done) == MPG123_OK)
  
  {
  
      char * resBuffer=&buffer[0]; //22100=0,5s
  
      buffer = resample(resBuffer,22100,22100);
  
      if((ao_play(dev, (char*)buffer, done)==0)){
  
          return 1;
  
  }

  resample() Using avcodec from ffmpeg

  #define LENGTH_MS 500       // how many milliseconds of speech to store
  
  #define RATE 44100      // the sampling rate (input)
  
  #define FORMAT PA_SAMPLE_S16NE  // sample size: 8 or 16 bits
  
  #define CHANNELS 2      // 1 = mono 2 = stereo
  
  
  
  struct AVResampleContext* audio_cntx = 0;
  
  
  
  char * resample(char in_buffer[(LENGTH_MS*RATE*16*CHANNELS)/8000],int out_rate,int nsamples)
  
  {
  
      char out_buffer[ sizeof( in_buffer ) * 4];
  
      audio_cntx = av_resample_init( out_rate, //out rate
  
          RATE, //in rate
  
          16, //filter length
  
          10, //phase count
  
          0, //linear FIR filter
  
          1.0 ); //cutoff frequency
  
      assert( audio_cntx && "Failed to create resampling context!");
  
      int samples_consumed;
  
      int samples_output = av_resample( audio_cntx, //resample context
  
          (short*)out_buffer, //buffout
  
          (short*)in_buffer,  //buffin
  
          &samples_consumed,  //&consumed
  
          nsamples,       //nb_samples
  
          sizeof(out_buffer)/2,//lenout
  
          0);//is_last
  
      assert( samples_output > 0 && "Error calling av_resample()!" );
  
      av_resample_close( audio_cntx );
  
      //*resample = malloc(sizeof(out_buffer));
  
      return &out_buffer[0];  
  
  }

  When i run this code i get 3393 Segmentation fault (core dump created). Why ?

  For example, the use of pointers is correct ?
  and 22100 are the samples that are contained in 0.5 seconds of the song ?

• How to add an album cover to an mp3 stream using FFmpeg ?

  29 décembre 2022, par Daniel LAPIDES

  I'm having a bit of an issue and I'd really appreciate it if I could get some insights.

  



  What I am trying to do is to add an album cover to the mp3 file that will be downloaded from the front-end.

  



  Context

  



  I'm downloading a video stream from YouTube and converting it to mp3 using fluent-ffmpeg.
  
To get the video I use the ytdl npm module.

  



  I then pipe this stream to the front-end.

  



  What I've found

  



  fluent-ffmpeg offers either pipe() or saveToFile().

  



  What I figured is that when I use the saveToFile() function and actually save my stream into an mp3 file, it works, I do get the album cover.

  



  But when I pipe the stream to front-end or even into a file, the song is saved properly into a file but without the album cover.

  



  Here is my code

  



  Back-end (NodeJS)

  



  let video = ytdl(`http://youtube.com/watch?v=${videoId}`, {
  filter: (format) => format.container === 'mp4' && format.audioEncoding,
  quality: 'lowest'
});

let stream = new FFmpeg()
  .input(video)
  .addInput(`https://i.ytimg.com/vi/${videoId}/default.jpg`)
  .outputOptions([
      '-map 0:1',
      '-map 1:0',
      '-c copy',
      '-c:a libmp3lame',
      '-id3v2_version 3',
      '-metadata:s:v title="Album cover"',
      '-metadata:s:v comment="Cover (front)"'
  ])
  .format('mp3');


  



  And then piping it to my front-end.

  



  stream.pipe(res);
stream
  .on('end', () => {
    console.log('******* Stream end *******');
    res.end.bind(res);
  })
  .on('error', (err) => {
    console.log('ERR', err);
    res.status(500).end.bind(res);
  });


  



  Front-end (React)

  



  axios.get(url)
  .then(res => {
    axios(`${url}/download`, {
      method: 'GET',
      responseType: 'blob'
    })
      .then(stream => {
        const file = new Blob(
          [stream.data],
          { type: 'audio/mpeg' });
        //Build a URL from the file
        const fileURL = URL.createObjectURL(file);
      })
      .catch(err => {
        console.log('ERROR', err);
      });
    })
    .catch(err => {
      console.log('ERROR', err);
    });