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• merge audio and video with ffmpeg without transcoding/encoding

  25 septembre 2019, par A Person

  Hi I hope you can help me with this query

  I have a video file with no Audio and 2 Audio files

  I am running the command

  ffmpeg -i video.mxf.m2v -i audio.mxf -i audio2.mxf -filter_complex "[1][2]amix=inputs=2[a]" -map 0:v -map "[a]" -c:v copy output.mxf
  

  Problem with this command is that for some reason the audio formatting change from the original setting.

  Original setting are:

  Video:

  Format : MPEG Video

  Format version : Version 2

  Format profile : 4:2:2@High

  Format settings : CustomMatrix / BVOP

  Format settings, BVOP : Yes

  Format settings, Matrix : Custom

  Format settings, GOP : M=3, N=12

  Format settings, picture structure : Frame

  Bit rate mode : Constant

  Maximum bit rate : 50.0 Mb/s

  Width : 1 920 pixels

  Height : 1 080 pixels

  Display aspect ratio : 16:9

  Frame rate : 25.000 FPS

  Standard : Component

  Color space : YUV

  Chroma subsampling : 4:2:2

  Bit depth : 8 bits

  Scan type : Interlaced

  Scan order : Top Field First

  Audio:

  Bits per sample = 24

  Bit Rate = 1152 kb/s

  48 Khz

  1 channel

  Audio track = 2

  The video seems to come out fine and no issues there but the audio comes out with the wrong spec.

  The output it gives is:

  Audio:

  Bits per sample = 16

  Bit Rate = 768 kb/s

  48 khz

  Audio Track = 1

  Is there a way for me to get the output and without transcoding and get back a file with the correct audio and video settings.

• Create and insert new FFMPEG packet to live stream

  25 septembre 2019, par TUrwin

  I'm currently receiving an FFMPEG encoded livestream and saving it directly to a .ts file.

  The data has 2 encoded streams: One for video, and one for KLV metadata.

  I have another dataset streaming in which is raw KLV data.

  What I want to achieve is to encode the raw KLV packet data into FFMPEG packets and mux them into the same .ts file as the other data streams without having to decode and re-encode the existing FFMPEG packets.

  Is there a way to achieve this?

• Streaming a video to /dev/video0 using gstreamer and v4l2 shows a black screen [on hold]

  24 septembre 2019, par Lawliet

  I've been trying to use a video as a webcam for quite a while now. The command

  gst-launch-1.0 filesrc location=newflag.webm ! decodebin ! videoconvert ! v4l2sink device=/dev/video0

  Using this command, i'm able to watch the stream using VLC but Discord and Firefox display a black screen when using /dev/video0 as a webcam.

  I got it working using ffmpeg to stream the video in yuv420p so I suspect videoconvert converts the stream to YUY2 which is I guess not supported by Discord nor Firefox.

  Any idea on how to get this to work ?

• How to remove PES header from video stream

  24 septembre 2019, par AnkurTank

  I have captured video stream from the multimedia device which has H264 format.

  I want to remove PES header (i.e. first 14 bytes of the frame). Is it possible to do it by ffmpeg or any other tool. I tried searching online but didn't find it. I thought of scripting it out and remove it but don't know frame format completely. I know, I have to learn all format stuffs and I am going through it but I need this immediately. Any suggestion/pointers ?

• ffmpeg - Merge back frames to a video with the same encoding

  24 septembre 2019, par Vuwox

  I have a video encoded using H264 at 23.98 fps, for a duration of 00:00:06.42.

  I extracted the frames from that video, and then I processed those images one-by-one. Now I want to put them back together as a video, but I want to be the same as the source video (same duration, same audio, etc).

  Whatever I tried gives something different. The duration is always greater (around 00:00:06.59), the audio seems to be up to the end of the video (as expected), but the frame are not encoded properly, and they seems to freeze at the end and the audio continue.

  The one that look almost the same except the freeze at the end look like this:

  ffmpeg -i input.mov \
         -pattern_type glob -i 'result_*.tif' 
         -map 1 -map 0:a \
         -map_metadata 0 \
         -map_metadata:s:v 0:s:v \
         -map_metadata:s:a 0:s:a \
         output.mov
  

  Where I use the metadata and the audio from the input video, and use the frames from my second input.

  EDIT: As suggested here the details of the source video.

  ffmpeg version 2.8.15 Copyright (c) 2000-2018 the FFmpeg developers
    built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-28)
    configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic' --extra-ldflags='-Wl,-z,relro ' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --disable-crystalhd --enable-gnutls --enable-ladspa --enable-libass --enable-libcdio --enable-libdc1394 --disable-indev=jack --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-openal --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libx264 --enable-libx265 --enable-libxvid --enable-x11grab --enable-avfilter --enable-avresample --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
    libavutil      54. 31.100 / 54. 31.100
    libavcodec     56. 60.100 / 56. 60.100
    libavformat    56. 40.101 / 56. 40.101
    libavdevice    56.  4.100 / 56.  4.100
    libavfilter     5. 40.101 /  5. 40.101
    libavresample   2.  1.  0 /  2.  1.  0
    libswscale      3.  1.101 /  3.  1.101
    libswresample   1.  2.101 /  1.  2.101
    libpostproc    53.  3.100 / 53.  3.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Transparent.mov':
    Metadata:
      major_brand     : qt
      minor_version   : 0
      compatible_brands: qt
      creation_time   : 2019-09-17 22:06:44
    Duration: 00:00:06.42, start: 0.000000, bitrate: 47798 kb/s
      Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 113 kb/s (default)
      Metadata:
        creation_time   : 2019-09-17 22:06:44
        handler_name    : Core Media Data Handler
      Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 47541 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 48k tbc (default)
      Metadata:
        creation_time   : 2019-09-17 22:06:44
        handler_name    : Core Media Data Handler
        encoder         : H.264
        timecode        : 00:00:00:00
      Stream #0:2(und): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
      Metadata:
        creation_time   : 2019-09-17 22:06:44
        handler_name    : Core Media Data Handler
        timecode        : 00:00:00:00
  At least one output file must be specified