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• RTP Timestamps Are Not Monotonically increasing

  25 août 2019, par Fr0sty

  I am finding it a bit difficult trying to understand whether or not the hack around with FFmpeg and OpenCV really provided a RTP timestamp. My last post helped a little bit but got me stuck in trying to validate the timestamps obtained through this work around by modifying ffmpeg and opencv.

  FFmpeg version : 4.1.0
  OpenCV version : 3.4.1

  import cv2
  
  import time
  
  from datetime import datetime, date
  
  
  
  uri = 'rtsp://admin:password@192.168.1.66:554/Streaming/Channels/101'
  
  cap = cv2.VideoCapture(uri)
  
  '''One is the offset between the two epochs. Unix uses an epoch located at 1/1/1970-00:00h (UTC) and NTP uses 1/1/1900-00:00h.
  
  This leads to an offset equivalent to 70 years in seconds (there are 17 leap years between the two dates so the offset is'''
  
  time_offset = 2208988800 # (70*365 + 17)*86400 = 2208988800 (in seconds)
  
  # offset = 3775484294
  
  days = 43697
  
  pdat = "1900-01-01 00:00:00:00"
  
  mdat = "2019-08-23 22:02:44:00" # str(datetime.now()) + str(datetime.now().time())
  
  pdate = datetime.strptime(pdat, "%Y-%m-%d %H:%M:%S:%f").date()
  
  mdate = datetime.strptime(mdat, "%Y-%m-%d %H:%M:%S:%f").date()
  
  delta = (mdate - pdate).days
  
  offset = delta * 86400
  
  def time_delta(s):
  
      return (s - time_offset)
  
  
  
  while True:
  
      frame_exists, curr_frame = cap.read()
  
      if frame_exists:
  
          seconds = cap.getRTPTimeStampSeconds()
  
          fraction = cap.getRTPTimeStampFraction()
  
          timestamp = cap.getRTPTimeStampTs()
  
          unix_offset = seconds - time_offset
  
          msec = int((int(fraction) / 0xFFFFFFFF) * 1000.0)
  
          ts = float(str(unix_offset) + "." + str(msec))
  
          # print("Timestamp per Frame:%i" % timestamp)
  
          print((datetime.fromtimestamp(float(ts) + offset)))
  
  cap.release()

  My Output :

  On August 23, 2019 at 22:02

  ...
  
  2019-08-23 13:59:52.781000
  
  2019-08-23 13:59:52.726000
  
  2019-08-23 13:59:52.671000
  
  2019-08-23 13:59:52.616000
  
  2019-08-23 13:59:52.561000
  
  2019-08-23 13:59:52.506000
  
  2019-08-23 13:59:52.451000
  
  2019-08-23 13:59:52.396000
  
  2019-08-23 13:59:52.342000
  
  2019-08-23 13:59:52.287000
  
  2019-08-23 13:59:52.232000
  
  2019-08-23 13:59:52.177000
  
  2019-08-23 13:59:52.122000
  
  2019-08-23 13:59:52.067000
  
  2019-08-23 13:59:52.012000
  
  2019-08-23 13:59:53.570000
  
  2019-08-23 13:59:53.020000
  
  2019-08-23 13:59:53.847000
  
  2019-08-23 13:59:53.792000

  I’ve noticed how the time increments weirdly (that’s not suppose to happen in the real, current time), such as the last two lines and a few others in between in the output. A bit flabbergasted as to what went wrong. Also trying this out on multiple IP cameras, with each showing a different timestamp probably related to when they were turned on.

• ffmpeg m4a/m4b/mp4 output file's "Time" value is incorrect when read into iTunes

  2 juin 2019, par PistoletPierre

  I’m using ffmpeg to convert audiobooks to m4a/m4b/mp4. All seems to work until trying to play them in iTunes. It plays in VLC, QuickTime, and MacOS’s Quicklook without issue.

  "So why are you posting here ? This isn’t an iTunes forum."

  I’m hoping this is iTunes being picky about file formats and that I can add some magic argument to my ffmpeg command and have it spit out something that iTunes can read.

  Below is the bash function I’m using to do the conversion. I’ve tried m4a/mp4/m4b as values for TEMP_FILE_EXTENSION and tried opening the intermediate file as well. It’s always the same corrupted "Time" value when you put it in iTunes.

  dedrm_audible () {
  
    # Check for AtomicParsley, ffmpeg, and 3 args
  
    if (! type AtomicParsley >/dev/null 2>/dev/null) || (! type ffmpeg >/dev/null 2>/dev/null) || [ ! $# -eq 3 ]; then
  
      echo "Usage:"
  
      echo "    dedrm_audible <path to="to"> <activation bytes="bytes"> <path to="to" output="output" file="file">"
  
      echo "    Note: AtomicParsley and ffmpeg must be in PATH variable"
  
      return
  
    fi
  
    local ORIGINAL_PWD="$(pwd)"
  
    local TEMP_DIR="/tmp/audible"
  
    local AUDIOBOOK_FILE="$1"
  
    local ACTIVATION_BYTES="$2"
  
    local OUTPUT_FILE="$3"
  
    local FULL_AUDIOBOOK_PATH="$(realpath "${AUDIOBOOK_FILE}")"
  
    local OUTPUT_PATH="$(realpath "${OUTPUT_FILE}")"
  
    local TEMP_FILE_EXTENSION="m4a"
  
  
  
    mkdir -p "${TEMP_DIR}"
  
    cd "${TEMP_DIR}"
  
  
  
    # Extract the book cover
  
    ffmpeg -activation_bytes "${ACTIVATION_BYTES}" -i "${FULL_AUDIOBOOK_PATH}" -vcodec copy artwork.png
  
    # Convert the audio
  
    ffmpeg -activation_bytes "${ACTIVATION_BYTES}" -i "${FULL_AUDIOBOOK_PATH}" -vn -c:a copy -v debug output.${TEMP_FILE_EXTENSION}
  
    # Add the cover to the new file
  
    AtomicParsley output.${TEMP_FILE_EXTENSION} --artwork artwork.png --overWrite
  
  
  
    # Put it where you want it and clean up
  
    cp output.${TEMP_FILE_EXTENSION} "${OUTPUT_PATH}"
  
    rm artwork.png
  
    rm output.${TEMP_FILE_EXTENSION}
  
    cd "${ORIGINAL_PWD}"
  
  }
  
  </path></activation></path>

  It goes off without a hitch. The new file is there waiting for me, with all the metadata including the cover when I do a "Get Info" or "Quick look" on it (I’m on MacOS). But when opening it and trying to play it in iTunes, the "time" field is way off and it immediately skips to the next song/audiobook in the queue.

  Attempts to convert it within iTunes fail immediately - too quickly to see what’s happening. The errors in the console simply say "Assert failure :" (with nothing after the colon).

  edit : Tommy answered the question. Here’s a working bash function :

  dedrm_audible () {
  
    # Check for AtomicParsley, ffmpeg, and 3 args
  
    if (! type AtomicParsley >/dev/null 2>/dev/null) || (! type ffmpeg >/dev/null 2>/dev/null) || [ ! $# -eq 3 ]; then
  
      echo "Usage:"
  
      echo "    dedrm_audible <path to="to"> <activation bytes="bytes"> <path to="to" output="output" file="file">"
  
      echo "    Note: AtomicParsley and ffmpeg must be in PATH variable"
  
      return
  
    fi
  
    local ORIGINAL_PWD="$(pwd)"
  
    local TEMP_DIR="/tmp/audible"
  
    local AUDIOBOOK_FILE="$1"
  
    local ACTIVATION_BYTES="$2"
  
    local OUTPUT_FILE="$3"
  
    # Alternative to realpath (since I read somewhere that it's not there by default on some systems): OUTPUT_PATH="$( cd "$( dirname "$OUTPUT_FILE" )" &amp;&amp; pwd )"
  
    local FULL_AUDIOBOOK_PATH="$(realpath "${AUDIOBOOK_FILE}")"
  
    local AUDIOBOOK_NAME="${$(basename "${FULL_AUDIOBOOK_PATH}")%.aax}.m4a"
  
    local OUTPUT_PATH="$(realpath "${OUTPUT_FILE}")"
  
    local TEMP_FILE_EXTENSION="m4a"
  
  
  
    mkdir -p "${TEMP_DIR}"
  
    cd "${TEMP_DIR}"
  
  
  
    cp "${FULL_AUDIOBOOK_PATH}" "${AUDIOBOOK_NAME}"
  
  
  
    # Extract the book cover
  
    ffmpeg -activation_bytes "${ACTIVATION_BYTES}" -i "${AUDIOBOOK_NAME}" -vcodec copy artwork.png
  
    # Convert the audio
  
    ffmpeg -activation_bytes "${ACTIVATION_BYTES}" -i "${AUDIOBOOK_NAME}" -vn -c:a copy -v debug output.${TEMP_FILE_EXTENSION}
  
    # Add the cover to the new file
  
    AtomicParsley output.${TEMP_FILE_EXTENSION} --artwork artwork.png --overWrite
  
  
  
    # Put it where you want it and clean up
  
    mv output.${TEMP_FILE_EXTENSION} "${OUTPUT_PATH}"
  
    rm artwork.png
  
    rm "${AUDIOBOOK_NAME}"
  
    cd "${ORIGINAL_PWD}"
  
  }
  
  </path></activation></path>

• Mix additional audio file with video(+audio) in ffmpeg

  21 mai 2019, par Serg

  I’m trying to mix additional audio file with video which has also audio within. But the problem is that I already have complex ffmpeg command and don’t know how to combine them together.

  This is my existing ffmpeg command which uses some offsets and replaces additional audio file with embedded one (audio inside video) and also overlays few gauges and watermark to the video.

  ffmpeg -y 
  
  -ss 00:00:01:213 -i videoFile.mp4 
  
  -ss 00:00:03:435 -i audioFile.wav 
  
  -i watermark.png 
  
  -framerate 6 -i gauge1_path/img-%04d.png 
  
  -framerate 1 -i gauge2_path/img-%04d.png 
  
  -framerate 2 -i gauge3_path/img-%04d.png 
  
  -framerate 2 -i gauge4_path/img-%04d.png 
  
  -framerate 2 -i gauge5_path/img-%04d.png 
  
  -framerate 2 -i gauge6_path/img-%04d.png 
  
  -filter_complex [0][2]overlay=(21):(H-h-21)[ovr0];
  
  [ovr0][3]overlay=(W-w-21):(H-h-21)[ovr1];
  
  [ovr1][4]overlay=(W-w-21):(H-h-333)[ovr2];
  
  [ovr2][5]overlay=(W-w-21):(H-h-418)[ovr3];
  
  [ovr3][6]overlay=(W-w-21):(H-h-503)[ovr4];
  
  [ovr4][7]overlay=(W-w-21):(H-h-588)[ovr5];
  
  [ovr5][8]overlay=(W-w-21):(H-h-673)
  
  -map 0:v -map 1:a -c:v libx264 -preset ultrafast -crf 23 -t 00:5:10:000 output.mp4

  Now I would like to use ffmpeg's amix in order to mix both audios instead of replacing them, if possible with ability to set volumes. But official documentation amix says nothing about volume.

  Separately both seems to work ok.

  ffmpeg -y -i video.mp4 -i audio.mp3 -filter_complex [0][1]amix=inputs=2[a] -map 0:v -map [a] -c:v copy output.mp4

  and

  ffmpeg -y -i video.mp4 -i audio.mp3 -i watermark.png -filter_complex [0][2]overlay=(21):(H-h-21)[ovr0] -map [ovr0]:v -map 1:a -c:v libx264 -preset ultrafast -crf 23 output.mp4

  but together

  ffmpeg -y -i video.mp4 -i audio.mp3 -i watermark.png -filter_complex [0][1]amix=inputs=2[a];[a][2]overlay=(21):(H-h-21)[ovr0] -map [ovr0]:v -map [a] -c:v libx264 -preset ultrafast -crf 23 output.mp4

  I’m getting an error :

  ffmpeg version N-93886-gfbdb3aa179 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with gcc 8.3.1 (GCC) 20190414
  
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  
    libavutil      56. 28.100 / 56. 28.100
  
    libavcodec     58. 52.101 / 58. 52.101
  
    libavformat    58. 27.103 / 58. 27.103
  
    libavdevice    58.  7.100 / 58.  7.100
  
    libavfilter     7. 53.101 /  7. 53.101
  
    libswscale      5.  4.101 /  5.  4.101
  
    libswresample   3.  4.100 /  3.  4.100
  
    libpostproc    55.  4.100 / 55.  4.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      creation_time   : 1970-01-01T00:00:00.000000Z
  
      encoder         : Lavf53.24.2
  
    Duration: 00:00:29.57, start: 0.000000, bitrate: 1421 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1032 kb/s, 25 fps, 25 tbr, 12800 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, 5.1, fltp, 383 kb/s (default)
  
      Metadata:
  
        creation_time   : 1970-01-01T00:00:00.000000Z
  
        handler_name    : SoundHandler
  
  [mp3 @ 0000015e2f934ec0] Estimating duration from bitrate, this may be inaccurate
  
  Input #1, mp3, from 'audio.mp3':
  
    Duration: 00:00:45.33, start: 0.000000, bitrate: 128 kb/s
  
      Stream #1:0: Audio: mp3, 44100 Hz, stereo, fltp, 128 kb/s
  
  Input #2, png_pipe, from 'watermark.png':
  
    Duration: N/A, bitrate: N/A
  
      Stream #2:0: Video: png, rgb24(pc), 100x56 [SAR 3779:3779 DAR 25:14], 25 tbr, 25 tbn, 25 tbc
  
  [Parsed_amix_0 @ 0000015e2ff2e940] Media type mismatch between the 'Parsed_amix_0' filter output pad 0 (audio) and the 'Parsed_overlay_1' filter input pad 0 (video)
  
  [AVFilterGraph @ 0000015e2f91c600] Cannot create the link amix:0 -> overlay:0
  
  Error initializing complex filters.
  
  Invalid argument

  So my question : whether it’s possible to combine amix and overlay together and how and in which order they should be used ? Or should I look something different because amix unable to set volume levels ?

  Thanks in advance !