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• avcodec/adpcm : Fix overflow in FFABS() IMA_EA_EACS

  7 décembre 2019, par Michael Niedermayer

  avcodec/adpcm : Fix overflow in FFABS() IMA_EA_EACS
  Fixes : negation of -2147483648 cannot be represented in type 'int' ; cast to an unsigned type to negate this value to itself
  
  Fixes : 19235/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ADPCM_IMA_EA_EACS_fuzzer-5680878952382464
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/adpcm.c

• FFMpeg kills itself when restreaming http to rtmp

  22 novembre 2019, par dust19992

  We are trying to restream few stations to our Emby server (alternative to plex), but always when we start the command as provided by many cast-software it runs for some time and then it dies.

  Here is our command :

  ffmpeg -i http://URL/IP:1515/station/discoverychannel/15HD -c:a aac -b:a 96k -ar 44100 -vcodec copy -f flv rtmp://server/discoverystation/15HD

  The error is none the only exit message is :

    Stream #0:0 -> #0:0 (copy)
  
    Stream #0:1 -> #0:1 (aac (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame=33056 fps= 60 q=-1.0 Lsize=  302387kB time=00:09:11.45 bitrate=4492.0kbits/s speed=1.01x
  
  video:295223kB audio:6576kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.194924%
  
  [aac @ 0x55b6a748ee40] Qavg: 583.684
  
  Exiting normally, received signal 2 
  
  root@simpsons:~#```
  
  
  
  
  
  Our server is WOWZA media server, and we have been looking for the problem for some time now, but without any success, so we hope you guys can help us figure it out, we are trying to copy the live video as it is, and we do not want to change the encoding, or anything else, but if necessary then it has to be encoded.
  
  
  
  I have not much experience in ffmpeg but we have been using VMIX that uses ffmpeg and it's running smooth there to the server without dying, so there has to be a way to run that with the ffmpeg standalone. 
  
  
  
  Here is the WOWZA restream manual: https://www.wowza.com/docs/how-to-restream-using-ffmpeg-with-wowza-streaming-engine
  
  
  
  Thanks.

• Python : How to decode a mp3 chunk into PCM samples ?

  30 mars 2021, par Bendzko

  I'm trying to catch chunks of an mp3 webstream and decoding them into PCM samples for signal processing. I tried to catch the audio via requests and io.BytesIO to save the data as .wav file.

  



  I have to convert the mp3 data to wav data, but I don't know how. (My goal is not to record a .wav file, i am just doing this to test the algorithm.)

  



  I found the pymedia lib, but it is very old (last commit in 2006), using python 2.7 and for me not installable.

  



  Maybe it is possible with ffmpeg-python, but I have just seen examples using files as input and output.

  



  Here's my code :

  



  import requests
import io
import soundfile as sf
import struct
import wave
import numpy as np


def main():
    stream_url = r'http://dg-wdr-http-dus-dtag-cdn.cast.addradio.de/wdr/1live/diggi/mp3/128/stream.mp3'
    r = requests.get(stream_url, stream=True)
    sample_array = []
    try:
        for block in r.iter_content(1024):
            data, samplerate = sf.read(io.BytesIO(block), format="RAW", channels=2, samplerate=44100, subtype='FLOAT',
                                       dtype='float32')
            sample_array = np.append(sample_array, data)

    except KeyboardInterrupt:
        print("...saving")
        obj = wave.open('sounds/stream1.wav', 'w')
        obj.setnchannels(1)  # mono
        obj.setsampwidth(2)  # bytes
        obj.setframerate(44100)

        data_max = np.nanmax(abs(sample_array))

        # fill WAV with samples from sample_array
        for sample in sample_array:
            if (np.isnan(sample) or np.isnan(32760 * sample / data_max)) is True:
                continue
            try:
                value = int(32760 * sample / data_max)  # normalization INT16
            except ValueError:
                value = 1
            finally:
                data = struct.pack('code>

  



  Do you have an idea how to handle this problem ?