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• Decode audio using ffmpeg (packet-by-packet) in Java

  27 mai 2022, par quad478

  In my application, I receive an audio stream from an IP-camera via RTP using NETTY.
The stream from IP-camera comes in the "G.711 mulaw" format, I would like to recode it to the "AAC" format.
I can't use files in this task as it's a live stream, and each packet needs to be decoded and delivered to the client (browser) immediately.
For this task, I wanted to use the ffmpeg child process :
when connecting to the camera, create a ffmpeg process and send to stdin (ffmpeg) each received packet, then I would like to receive the decoded packet from stdout.
Here is the command I run ffmeg with :

  


  "ffmpeg.exe -f mulaw -re -i - -f adts -"


  


  I'm not sure if "-re" should be used here, but without this option, ffmpeg outputs the decode result only after stdin is closed and the process exits.
The problem is that I don't get anything on stdout after sending the packet to ffmpeg.

  


  Decoder code :

  


  package ru.ngslab.insentry.web.video.protocols.rtp;&#xA;&#xA;import io.netty.buffer.ByteBuf;&#xA;import io.netty.channel.ChannelHandlerContext;&#xA;import io.netty.handler.codec.MessageToMessageDecoder;&#xA;&#xA;import java.io.Closeable;&#xA;import java.io.IOException;&#xA;import java.io.InputStream;&#xA;import java.io.OutputStream;&#xA;import java.util.List;&#xA;import java.util.concurrent.ExecutorService;&#xA;import java.util.concurrent.Executors;&#xA;import java.util.concurrent.Future;&#xA;&#xA;public class RtpFfmpegDecoder extends MessageToMessageDecoder<rtppacket> implements Closeable {&#xA;&#xA;    private final Process ffmegProcess;&#xA;    private final OutputStream ffmpegOutput;&#xA;    private final InputStream ffmegInput;&#xA;    private final ExecutorService ffmpegInputReaderService = Executors.newSingleThreadExecutor();&#xA;&#xA;    public RtpFfmpegDecoder() {&#xA;&#xA;        //Start Ffmpeg process&#xA;        ProcessBuilder ffmpegBuilder = new ProcessBuilder("ffmpeg.exe", "-f", "mulaw",&#xA;                "-re", "-i", "-", "-f", "adts", "-").redirectError(ProcessBuilder.Redirect.INHERIT);&#xA;        try {&#xA;            ffmegProcess = ffmpegBuilder.start();&#xA;            ffmpegOutput = ffmegProcess.getOutputStream();&#xA;            ffmegInput = ffmegProcess.getInputStream();&#xA;        } catch (IOException e) {&#xA;            throw new IllegalStateException(e);&#xA;        }&#xA;    }&#xA;&#xA;    @Override&#xA;    protected void decode(ChannelHandlerContext channelHandlerContext, RtpPacket rtpPacket, List list) throws Exception {&#xA;&#xA;        //start read ffmpeg output in another thread&#xA;        Future future = ffmpegInputReaderService.submit(this::startReadFFmpegOutput);&#xA;&#xA;        //write rtp- packet bytes to ffmpeg-input&#xA;        ByteBuf data = rtpPacket.getData();&#xA;        byte[] rtpData = new byte[data.readableBytes()];&#xA;        data.getBytes(data.readerIndex(), rtpData);&#xA;        ffmpegOutput.write(rtpData);&#xA;        ffmpegOutput.flush();&#xA;&#xA;        //waiting here for the decoding result from ffmpeg&#xA;        //blocks here&#xA;        byte[] result = future.get();&#xA;        //then process result...&#xA;    }&#xA;&#xA;    private byte[] startReadFFmpegOutput() {&#xA;        try {&#xA;            //I don&#x27;t know how many bytes to expect here, for test purposes I use 1024&#xA;            var bytes = new byte[1024];&#xA;            ffmegInput.read(bytes);&#xA;            return bytes;&#xA;        } catch (IOException e) {&#xA;            throw new IllegalStateException(e);&#xA;        }&#xA;    }&#xA;&#xA;    @Override&#xA;    public void close() throws IOException {&#xA;        //Close streams code...&#xA;    }&#xA;}&#xA;</rtppacket>

  


  This doesn't work because ffmpeg doesn't send anything after receiving the packet.
No errors in log, no output data.
Just wait for result here :

  


  byte[] result = future.get();


  


  Normally, ffmpeg only outputs after stdin is closed and the process stops.
It may be necessary to run ffmpeg with some special
parameters so that it outputs each received packet at once ?

  


  I would be very grateful for any help

  


• Build ffmpeg on a build machine

  18 juillet 2019, par RDI

  Build ffmpeg on build PC using libx264 and shared libraries (not static).
  I am building on a Red Hat 6.6 Server and final target machine is CentOS 6.6.
  I am trying, as said, to build ffmpeg with encoding enabled (with libx264) and shared libraries ; of course I do not want to install the libraries on the build PC, they should be only extracted and then delivered together with the final RPM.
  After the "./configure" I get all RPMs (related to ffmpeg) but when trying to installing ffmpeg-libs on the build pc it fails because the libx264.so.157 is not found, even if as test I installed it (configure/make/make install) and present at /usr/local/lib.

  Where am I wrong ?

  Thanks

  This is my SPEC file at the moment :

  ldconfig /usr/local/lib
  
  export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH
  
  
  
  
  
  # configure 
  
  ./configure \
  
   --enable-gpl --disable-static --enable-shared --extra-cflags="-I/usr/local/include" --extra-ldflags="-L/usr/local/lib" --extra-libs=-ldl --disable-autodetect --disable-doc --disable-postproc --disable-ffplay --disable-everything --enable-encoder=aac --enable-encoder=png --enable-encoder=mjpeg --enable-encoder=libx264 --enable-decoder=aac --enable-decoder=h264 --enable-decoder=mpeg4 --enable-decoder=rawvideo --enable-decoder=png --enable-muxer=mp4 --enable-muxer=stream_segment --enable-muxer=image2 --enable-demuxer=aac --enable-demuxer=h264 --enable-demuxer=mov --enable-demuxer=rtp --enable-parser=aac --enable-parser=h264 --enable-parser=mpeg4video --enable-bsf=aac_adtstoasc --enable-protocol=file --enable-protocol=http --enable-protocol=tcp --enable-protocol=rtp --enable-protocol=udp --enable-indev=xcbgrab --disable-alsa --enable-libxcb --enable-libxcb-xfixes --enable-libxcb-shape --enable-zlib --prefix=%{_prefix} --bindir=%{_bindir} --datadir=%{_datadir}/%{name} --shlibdir=%{_libdir} --enable-alsa --enable-avfilter --enable-avresample --enable-libx264 --enable-filter=scale \

• Applying same filter_complex many times before output [duplicate]

  19 août 2019, par Fabián

  This question already has an answer here :

  • FFmpeg command to apply multiple filters and limit the final file size [closed]
    
    1 answer
    
  • Applying multiple filters at once with FFMPEG
    
    2 answers
    
  • FFMpeg - Combine multiple filter_complex and overlay functions
    
    1 answer
    
  • ffmpeg : multiple video filter order issue
    
    1 answer
    

  It’s not a duplicate. This is about using filter_complex, not -vf.

  In my video there’s an object that has shades of yellow (more orange-like) and a solid yellow as background.

  I need to output all frames into a png sequence, using a color key filter to replace the yellow from the background :

  ffmpeg -ss 4 -i original.mp4 -t 2 -filter_complex "[0:v]colorkey=0xfff31b:0.125:0[ckout]" -map "[ckout]" colorkey-%d.png

  This removes the specific color, but leaves some pints behind, and some items are yellow-themed, so blending value is a no-no for this scenario.

  I need to get rid of 4 specific yellow-colors from the frames : 0xfff31b, 0xfae56b, 0xfaec46 and 0xeee2a0, and I plan to run the same filter for specific colors before getting the final result.

  So first I tried this :

  ffmpeg -ss 4 -i original.mp4 -t 2 -filter_complex "[0:v]colorkey=0xfff31b:0.4:0[ckout1];[0:v]colorkey=0xfae56b:0.4:0[ckout2];[0:v]colorkey=0xfaec46:0.4:0[ckout3];[0:v]colorkey=0xeee2a0:0.4:0[ckout4]" -map "[ckout4]" colorkeyrefined-%d.png

  Then this :

  ffmpeg -ss 4 -i original.mp4 -t 2 -filter_complex "[0:v]colorkey=0xfff31b:0.4:0[ckout]" -filter_complex "[0:v]colorkey=0xfae56b:0.4:0[ckout]" -filter_complex "[0:v]colorkey=0xfaec46:0.4:0[ckout]" -filter_complex "[0:v]colorkey=0xeee2a0:0.4:0[ckout]" -map "[ckout]" colorkeyrefined-%d.png

  But both display the same error :

  Filter colorkey has an unconnected output.

  Is there a way to apply the colorkey feature 4 times (with the mentioned values) in one go ?