Recherche avancée

Sur d’autres sites (11067)

• how to extract a metadata track from MP4 file

  30 août 2019, par ravi

  I need to extract metadata track from a MP4 file and save as separate file. I see that, using ffmpeg I can extract standard tracks like Audio or Video or Subtitle track and save it as a new file. For ex : to save audio track I use the command below :

  ffmpeg -i input-video.avi -vn -acodec copy output-audio.aac

  But my need is to save a proprietary metadata track. Any pointers will be helpful.

  Here is output of ffmpeg to know different traks that are present in the file. Particuarly, I am interested in extracting track corresponding to Stream #0:3(eng)...

  C:\Users\rkumar\Documents\work\tools\ffmpeg\bin>ffmpeg.exe -i input.MP4
  
  ffmpeg version N-57176-g64b3aaf Copyright (c) 2000-2013 the FFmpeg developers
  
  built on Oct 15 2013 21:32:52 with gcc 4.8.1 (GCC)
  
  
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.MP4':
  
  Metadata:
  
  major_brand     : mp41
  
  minor_version   : 538120216
  
  compatible_brands: mp41
  
  creation_time   : 1970-01-01 00:00:09
  
  Duration: 00:00:10.52, start: 0.000000, bitrate: 834 kb/s
  
  
  
  Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuvj420p(pc, bt709), 
  
  854x480 [SAR 1:1 DAR 427:240], 679 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc (default)
  
  Metadata:
  
  creation_time   : 1970-01-01 00:00:09
  
  handler_name    : AVC
  
  timecode        : 00:00:13:22
  
  
  
  Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
  
  Metadata:
  
  creation_time   : 1970-01-01 00:00:09
  
  handler_name    : AAC
  
  timecode        : 00:00:13:22
  
  
  
  Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
  
  Metadata:
  
  creation_time   : 1970-01-01 00:00:09
  
  handler_name    : TCD
  
  timecode        : 00:00:13:22
  
  
  
  Stream #0:3(eng): Data: none (ssmd / 0x646D7067), 5 kb/s (default)
  
  Metadata:
  
  creation_time   : 1970-01-01 00:00:09
  
  handler_name    : MET
  
  
  
  Stream #0:4(eng): Data: none (fdsc / 0x63736466), 10 kb/s (default)
  
  Metadata:
  
  creation_time   : 1970-01-01 00:00:09
  
  handler_name    : SOS

• 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>