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• Loss of frames results in a memory leak in the FFmpeg H.264 decoder

  9 octobre 2013, par user2863509

  guys !

  I am using FFmpeg library 'avcodec' in my VOIP-application for decoding streaming video in H.264 format. Video stream is transmitted over the network via RTP. I am using function avcodec_decode_video2() to decode H.264 frames received from the network.

  I've used valgrind with tool 'massif' and found the memory leaks in the function avcodec_decode_video2().

  I've discovered that the leaks occur when there is a loss of RTP packets before receiving the first INTRA frame (keyframe). The leak is directly proportional to the time which passes from the moment the first call avcodec_decode_video2() until arrival of the next INTRA frame (keyframe).

  Question 1 : Has anyone seen this behavior function avcodec_decode_video2() ?

  Question 2 : There is a suspicion that the decoder allocates memory for data and does not release it after the arrival of good keyframe. How to bring back the memory in heap ?

  Thank all !

• node.js ffmpeg spawn child_process unexpected data output and not possible to kill or stop

  1er septembre 2021, par PLNR

  
I'm rather new to backend stuff, so please excuse, if my question is trivial.
  
For an Intranet project, I want to present a video element in a webpage (React, HLS.js Player) with the possibility reload the stream in case it hung.
  
The video sources are mpeg-ts streams delivered as udp multicast.
  
A small node.js / express server should handle the ffmpeg commands, to transcode the multicast to hls to display them in a browser.
  

  
My Problem is, that I am unable to stop the process...
  
I've tried to SIGINT, SIGTERM the process with it's pid, but the encoding is just going on.

  


  Here is the code I wrote for transcoding so far :

  


  const express = require("express");
const { spawn, exec } = require("child_process");
const cors = require("cors");
const process = require("process")

let ls;
let pid;

const app = express();

app.use(cors());

app.get('/cam/:source', (body) => {
    const cam = body.params.source;
    console.log(cam);

    let source = "udp://239.1.1.1:4444";
    let stream = "/var/www/html/streams/tmp/cam1.m3u8"


    stream = spawn("ffmpeg", ["-re", "-i", source, "-c:v", "libx264", "-crf", "21", "-preset", "veryfast", "-c:a", "aac", "-b:a", "128k", "-ac", "2", "-f", "hls", "-hls_list_size", "5", "-hls_flags", "delete_segments", stream], {detached: true});

    pid = stream.pid;

    stream.stdout.on("data", data => {
        console.log(`stdout: ${data}`);
    });

    stream.stderr.on("data", data => {
        console.log(`stderr: ${data}`);
        console.log("pid: ", pid);
    });

    stream.on("error", error => {
        console.log(`error: ${error.message}`);
    });

    stream.on("close", code => {
        console.log(`child process exited with code ${code}`);
    });
})

app.get('/cam/quit', () => {
    process.kill(pid, 'SIGINT')
})

app.listen(5000, ()=> {
    console.log('Listening');
})


  


  On requesting the /cam/quit i would expect the process to stop... but it doesn't.
  
I've tried :

  


  app.get('/cam/quit', () => {
    process.kill(pid, 'SIGINT')
})


  


  app.get('/cam/quit', () => {
    process.kill(stream.pid, 'SIGINT')
})


  


  app.get('/cam/quit', () => {
    stream.kill(pid, 'SIGINT')
})


  


  app.get('/cam/quit', () => {
    stream.kill(0, 'SIGINT')
})


  


  But none of this worked... do I miss something ? Is there something I need to change ?

  


  Problem 2 - Output :
  
The output is emitted on stderr... even the process is working as expected.
  
This is maybe only cosmetics, but it makes me wondering.
  
Here is the terminal output :

  


  [nodemon] starting `node server.js`
Listening
camera stream reloaded
stderr: ffmpeg version 4.3.2-0+deb11u1ubuntu1 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 10 (Ubuntu 10.2.1-20ubuntu1)
  configuration: --prefix=/usr --extra-version=0+deb11u1ubuntu1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100

pid:  4206
stderr: Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'udp://239.1.1.1':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    creation_time   : 
pid:  4206
stderr: 1970-01-01T00:00:00.000000Z
    encoder         : Lavf52.54.0
  Duration: 01:55:59.20, start: 0.000000, bitrate: 1436 kb/s
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 720x384 [SAR 1:1 DAR 15:8], 1272 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 159 kb/s (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : SoundHandler

pid:  4206
stderr: Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help

pid:  4206
stderr: [libx264 @ 0x5616b38b5440] using SAR=1/1

pid:  4206
stderr: [libx264 @ 0x5616b38b5440] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2

pid:  4206
stderr: [libx264 @ 0x5616b38b5440] profile High, level 3.0, 4:2:0, 8-bit

pid:  4206
stderr: [libx264 @ 0x5616b38b5440] 264 - core 160 r3011 cde9a93 - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - http://www.videolan.org/x264.html - options: cabac=1 ref=1 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=6 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=10 rc=crf mbtree=1 crf=21.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, hls, to '/var/www/html/streams/tmp/aft.m3u8':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
    Stream #0:0(und): Video: h264 (libx264), yuv420p, 720x384 [SAR 1:1 DAR 15:8], q=-1--1, 25 fps, 90k tbn, 25 tbc (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : VideoHandler
      encoder         : Lavc58.91.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
    Stream #0:1(und): Audio: aac (LC), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : SoundHandler
      encoder         : Lavc58.91.100 aac

pid:  4206
stderr: frame=    8 fps=0.0 q=0.0 size=N/A time=00:00:00.46 bitrate=N/A speed=0.931x    
pid:  4206
stderr: frame=   21 fps= 21 q=26.0 size=N/A time=00:00:00.96 bitrate=N/A speed=0.95x    
pid:  4206
stderr: frame=   33 fps= 22 q=26.0 size=N/A time=00:00:01.49 bitrate=N/A speed=0.982x    
pid:  4206
stderr: frame=   46 fps= 23 q=26.0 size=N/A time=00:00:02.00 bitrate=N/A speed=0.989x    
pid:  4206
stderr: frame=   58 fps= 23 q=26.0 size=N/A time=00:00:02.49 bitrate=N/A speed=0.986x    
pid:  4206


  


  and so on...
  

  
Any help would be highly appreciated !
  
Many thanks in advance

  


• Node.js - Buffer Data to Ffmpeg

  24 septembre 2017, par user8568709

  I used Node.js and Ffmpeg to create animations. Because I was trying to avoid third-party avi/mp4 parsers, I decided to output the animation as raw rgb24 data file and then use some program to convert it to mp4 file.

  I found that Ffmpeg is free and open source which can do exactly it. So, I made a Node.js application which allocates a Buffer of size 1920 x 1080 x 3 (width times height times number of bytes per pixel), then I created a rendering context library, and finally I animated frame by frame and saved each frame consecutivelly in a binary file (using fs module).

  Then I invoked Ffmpeg to convert it to mp4 file and it works very good. Animations are pretty easy to make and Ffmpeg does its job correctly.

  However, the only problem is because it is very slow and eats space on hard disk. I want to create very long animations (more than a hour). The final mp4 file is relativelly small, but raw video file is extremelly big. About ninety percents of each frame are black pixels, so Ffmpeg comress it very good, but raw file cannot be compressed and it takes sometimes mor ethan 100 Gigabytes. Also, there is very unnecessary double processing same data. Firstly I process it in Node.js to save data to file, and then Ffmpeg reads it to convert it to mp4. There is a lot of unnecessary work.

  So, I’m looking for a way (and I’m pretty sure it is possible, but I didn’t find a way to do it yet) to output raw video data (one frame at a time) to Ffmpeg process (without saving anything to the hard disk).

  My goal is to do the following :

  1. Open Ffmpeg process
  2. Render a frame in Node.js
  3. Output raw byte stream to Ffmpeg
  4. Wait for Ffmpeg to encode it and append to mp4 file
  5. Let Ffmpeg wait for my Node.js process to render next frame

  ---

  Is there a way to achieve it ? I really don’t see a reason to post code, because my current code has nothing to do with the question I’m asking here. I don’t struggle with syntax errors or implementation problems. No, instead I just don’t know which parameters to pass to Ffmpeg process in order to achieve what I’ve already explained.

  I’ve searched in documentation to find out which parameters I need to pass to Ffmpeg process in order to let it read raw data from stdin instead from file, and also to wait until my Node.js process render next frame (so to disable time limit) because rendering a frame may take more than 24 hours. Therefore, Ffmpeg process should wait without time limit. However, I didn’t find anything about it in documentation.

  I know how to write to stdin from Node.js and similar technical stuff, so no need to explain it. The only question(s) here :

  1. Which parameters to pass to Ffmpeg ?
  2. Do I need to create Ffmpeg process (using child_process) with some special options ?

  ---

  Thank you in advance. Please, take it easy, this is my first question ! :)