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• how can use openrtsp to change audio sample-rate ?

  10 septembre 2015, par Bilel Eljaamii

  I use openRTSP to get audio from my IP Camera, When I try to open it with Audacity or ffplayer (ffmpeg player) ffplay audio-PCMA-2 the audio speed was very high.

  I changed the sample rate to 8000 and I get a normal audio speed. I tried to change it the ffmpeg library but without any positive result.

  ffmpeg  -i video-H264-1 -i audio-PCMA-2.al  -strict experimental -sample_rate 8000 -f alaw -acodec aac -ab 64k -ar 44100 -f mpegts test.ts

  How can I use openrtsp to change the bit sample-rate ?
  the command wich i use to get the stream is

  ./openRTSP "rtsp://user:pass@IP_CAMERA/....."

• error convert sample rate from AV_SAMPLE_FMT_FLTP to AV_SAMPLE_FMT_S16

  10 avril 2013, par user1881371

  convert sample rate from AV_SAMPLE_FMT_FLTP to AV_SAMPLE_FMT_S16 and play the openAL, get the following error(http://joxi.ru/B_JkUdg5CbDrWhe9oNI)

  CONV_FUNC (AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, av_clip_int16 (lrintf (* (const float *) pi * (1 << 15))))

  in file audioconvert.c

  my code

  swrContext = swr_alloc();
  
  av_opt_set_int(swrContext, "in_channel_layout",  cc->channel_layout, 0);
  
  av_opt_set_int(swrContext, "out_channel_layout", cc->channel_layout,  0);
  
  av_opt_set_int(swrContext, "in_sample_rate",     cc->sample_rate, 0);
  
  av_opt_set_int(swrContext, "out_sample_rate",    cc->sample_rate, 0);
  
  av_opt_set_sample_fmt(swrContext, "in_sample_fmt",  cc->sample_fmt, 0);
  
  av_opt_set_sample_fmt(swrContext, "out_sample_fmt", AV_SAMPLE_FMT_S16P,  0);
  
  swr_init(swrContext);
  
  
  
  uint8_t *output;
  
  int out_samples = (int)av_rescale_rnd(swr_get_delay(swrContext, 44100) + (int64_t)decoded_frame->nb_samples, 44100, 44100, AV_ROUND_UP);
  
  swr_convert(swrContext, &output, out_samples, (const uint8_t **)decoded_frame->extended_data, decoded_frame->nb_samples); //error
  
  alBufferData(BufID,AL_FORMAT_STEREO16,output, decsize,44100);

  may have other solutions ?

  may have other solutions ? I'm doing on the How to convert sample rate from AV_SAMPLE_FMT_FLTP to AV_SAMPLE_FMT_S16 ?

• Matplotlib use Ffmpeg to save plot to be mp4 not include full step

  21 décembre 2020, par 昌翰余

  I use ffmpeg to store the dynamic graph drawn on matplotlib, but the output file is only 2 seconds
but It should have been 30 seconds.
I set a graph to run three curves, a total of 30 seconds of data,
the graph that ran on the py file is normal,
but the output is only the first two seconds of the output.
May I ask if I missed something

  


  Below is my code

  


  import matplotlib.pyplot as plt
from matplotlib import animation
from numpy import random 
import pandas as pd
from matplotlib.animation import FFMpegWriter

FFwriter=animation.FFMpegWriter(fps=30, extra_args=['-vcodec', 'libx264'])
data = pd.read_csv('apple1.csv', delimiter = ',', dtype = None)
data = data.values
AccX1=[]
AccY1=[]
AccZ1=[]
AccX2=[]
AccY2=[]
AccZ2=[]

time = []

for i in range(600):
        AccX1.append(data[i][8])
        AccY1.append(data[i][9])
        AccZ1.append(data[i][10])
        AccX2.append(data[i][24])
        AccY2.append(data[i][25])
        AccZ2.append(data[i][26])
        
        time.append(data[i][0])
        
fig = plt.figure()
ax1 = plt.axes(xlim=(0,3000), ylim=(6,-6))
line, = ax1.plot([], [], lw=2)
plt.xlabel('ACC')
plt.ylabel('Time')

plotlays, plotcols = [3], ["r","g","b"]
lines = []
for index in range(3):
    lobj = ax1.plot([],[],lw=2,color=plotcols[index])[0]
    lines.append(lobj)


def init():
    for line in lines:
        line.set_data([],[])
    return lines

x1,y1 = [],[]
x2,y2 = [],[]
x3,y3 = [],[]



i=0

def animate(frame):
    global i
    
    i+=1
    x = i
    y = AccX1[i]

    x1.append(x)
    y1.append(y)

    x = i
    y = AccY1[i]
    x2.append(x)
    y2.append(y)

    x = i
    y = AccZ1[i]
    x3.append(x)
    y3.append(y)
    

    xlist = [x1, x2,x3]
    ylist = [y1, y2,y3]


    for lnum,line in enumerate(lines):
        line.set_data(xlist[lnum], ylist[lnum]) 


    return lines


anim = animation.FuncAnimation(fig, animate,
                    init_func=init, blit=True,interval=10)
anim.save('test.mp4',writer=FFwriter)
plt.show()


  


  The dynamic picture ran out using plt.show is correct.
And I don't think I have set the length of storage. Did I add something ?