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• FFMPEG PHP Message : Unable to save frame

  30 avril 2020, par Hitesh Vala Ahir

  Hello I have try to take thumbnail through FFMPEG but get the error message like Message : Unable to save frame.

  



  PHP 7.0

  



  php-ffmpeg/php-ffmpeg : ^0.16.0

  



  Below is the code

  



  require &#x27;vendor/autoload.php&#x27;;&#xA;&#xA;&#xA;&#xA;$sec =1;&#xA;$movie = &#x27;video1581091620.mp4&#x27;;&#xA;$thumbnail = &#x27;thumbnail.png&#x27;;&#xA;&#xA;try{&#xA;$ffmpeg = FFMpeg\FFMpeg::create();&#xA;$video = $ffmpeg->open($movie);&#xA;$frame = $video->frame(FFMpeg\Coordinate\TimeCode::fromSeconds($sec));&#xA;$frame->save($thumbnail);&#xA;echo &#x27;<img src="http://stackoverflow.com/feeds/tag/&#38;#x27;.$thumbnail.&#38;#x27;" style='max-width: 300px; max-height: 300px' />&#x27;;&#xA;}catch(Exception $e) {&#xA;  echo &#x27;Message: &#x27; .$e->getMessage();&#xA;}&#xA;

  


• Matplotlib can not save animation

  1er avril 2020, par Justin Furuness

  I have a matplotlib animation and it will not save. If I do not save it, it runs totally fine and without error. When I try to save it errors with a message that is not helpful. I have googled this error and checked everything, but I cannot seem to find an answer to this problem. I have installed ffmpeg. Am I doing something wrong that is obvious ? I am running on ubuntu 19.10 with matplotlib 3.2.1 if that matters.

  



  The code to save the animation is below :

  



      def run_animation(self, total_rounds):
        anim = animation.FuncAnimation(self.fig, self.animate,
                                       init_func=self.init,
                                       frames=total_rounds * 100,
                                       interval=40,
                                       blit=True)
#        Writer = animation.writers['ffmpeg']
#        writer = Writer(fps=15, metadata=dict(artist='Me'), bitrate=1800)
        anim.save('animation.mp4')


  



  The error traceback :

  



  2020-04-01 02:20:58,279-INFO: MovieWriter._run: running command: ffmpeg -f rawvideo -vcodec rawvideo -s 1200x500 -pix_fmt rgba -r 25.0 -loglevel error -i pipe: -vcodec h264 -pix_fmt yuv420p -y animation.mp4
Traceback (most recent call last):
  File "/home/anon/.local/lib/python3.7/site-packages/matplotlib/backend_bases.py", line 2785, in _wait_cursor_for_draw_cm
    self.set_cursor(cursors.WAIT)
  File "/home/anon/.local/lib/python3.7/site-packages/matplotlib/backends/backend_gtk3.py", line 468, in set_cursor
    self.canvas.get_property("window").set_cursor(cursord[cursor])
AttributeError: 'NoneType' object has no attribute 'set_cursor'


  



  Thanks a million for your help

  


• Save a Twilio of format 8Khz `mulaw` to a file

  2 avril 2020, par Joe

  There are a couple of posts that address the question, but I wasn't able to successfully playback a saved file. It usually plays back at half speed.

  



  Convert 8kHz mulaw to 16KHz PCM in real time

  



  Using the accepted answer in the above question, I saved the raw and base64 decoded the audio in go :

  



  // Media event
type Media struct {
    Track     string `json:"track"`
    Chunk     string `json:"chunk"`
    Timestamp string `json:"timestamp"`
    Payload   string `json:"payload"`
}

// SaveAudio will upgrade connection to websocket and save the audio to file
func SaveAudio(w http.ResponseWriter, r *http.Request) {
    utility.DebugLogf("SaveAudio")
    c, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Print("upgrade:", err)
        return
    }

    defer utility.SafeClose(c)
    inBuf := bytes.Buffer{}

    loop := true
    for loop == true {
        _, message, err := c.ReadMessage()
        utility.PanicIfErr(err)
        decMessage := TwilioWSSMessage{}
        err = json.Unmarshal(message, &decMessage)
        utility.PanicIfErr(err)

        switch decMessage.Event {
        case "connected":
            utility.DebugLogf("Connected a %s protocol version:%s", decMessage.Protocol, decMessage.Version)
        case "start":
            utility.DebugLogf("Starting audio stream: %#v", decMessage.Start)
        case "media":
            chunk, err := base64.StdEncoding.DecodeString(decMessage.Media.Payload)
            utility.PanicIfErr(err)
            _, err = inBuf.Write(chunk)
            utility.PanicIfErr(err)
        case "stop":
            utility.DebugLogf("Ending audio stream: %#v", decMessage.Stop)
            loop = false
        default:
            utility.LogWarningf("Unrecognized event type: %s", decMessage.Event)
            loop = false
        }
    }

    saveRaw(&inBuf)
}

func saveRaw(buf *bytes.Buffer) {
    rawOut, err := os.Create("out.ulaw")
    utility.PanicIfErr(err)

    _, err = rawOut.Write(buf.Bytes())
    utility.PanicIfErr(err)
}


  



  Then I used ffmpeg to convert from mulaw to the default pcm_s16le :

  



  ffmpeg -f mulaw -ar 8000 -ac 1 -i out.ulaw mulaw_decoded.wav 


  



  Then upsampled the audio from 8k->16k and play it with vlc :

  



  ffmpeg -i mulaw_decoded.wav -ar 16000 upsampled.wav && vlc upsampled.wav


  



  But it plays at half speed.

  



  Ultimately I'd like to do it all in rust or go, but I can't even get it working locally with just ffmpeg.

  



  Thanks in advance.

  



  ---

  



  output of the above two ffmpeg operations combined with the suggested sox resampler :

  



  cmd :

  



  ffmpeg -y -loglevel verbose -f mulaw -ar 8000 -ac 1 -bits_per_raw_sample 8 -i testsamples/raw_mulaw_bytes -af aresample=resampler=soxr -ar 16000 upsampled.wav


  



  output :

  



  [mulaw @ 0x7fecc0814000] Estimating duration from bitrate, this may be inaccurate
Guessed Channel Layout for Input Stream #0.0 : mono
Input #0, mulaw, from 'testsamples/raw_mulaw_bytes':
  Duration: 00:00:20.74, bitrate: 64 kb/s
    Stream #0:0: Audio: pcm_mulaw, 8000 Hz, mono, s16, 64 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_mulaw (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
[graph_0_in_0_0 @ 0x7fecc0505600] tb:1/8000 samplefmt:s16 samplerate:8000 chlayout:0x4
[Parsed_aresample_0 @ 0x7fecc0505280] ch:1 chl:mono fmt:s16 r:8000Hz -> ch:1 chl:mono fmt:s16 r:16000Hz
Output #0, wav, to 'upsampled.wav':
  Metadata:
    ISFT            : Lavf58.29.100
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 16000 Hz, mono, s16, 256 kb/s
    Metadata:
      encoder         : Lavc58.54.100 pcm_s16le
No more output streams to write to, finishing.
size=     648kB time=00:00:20.74 bitrate= 256.0kbits/s speed=1.55e+03x
video:0kB audio:648kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.011753%
Input file #0 (testsamples/raw_mulaw_bytes):
  Input stream #0:0 (audio): 519 packets read (165920 bytes); 519 frames decoded (165920 samples);
  Total: 519 packets (165920 bytes) demuxed
Output file #0 (upsampled.wav):
  Output stream #0:0 (audio): 200 frames encoded (331840 samples); 200 packets muxed (663680 bytes);
  Total: 200 packets (663680 bytes) muxed
[AVIOContext @ 0x7fecc0433cc0] Statistics: 4 seeks, 6 writeouts
[AVIOContext @ 0x7fecc042a6c0] Statistics: 165920 bytes read, 0 seeks


  



  The audio sounds the same as before