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• FFmpeg get frames equally spaced out from video

  2 décembre 2017, par TheOtherguyz4kj

  I am having some real problems with FFmpeg in my Android application. I am currently trying to take a video recorded from the device and extract frames from the video equally throughout the video. I used this blog post. The last formula :

  ffmpeg -i input.avi -f image2 -ss 2 -r 0.05 frame-%05d.png

  with my own -ss and own -r values.

  Now everything is fine. Like mentioned in the blog the first 2 frames are the same for some reason. So i delete one of the frames then I feel as though the frames accurately show the video. In the blog it also says to delete some of the last frames I dont do this because then i dont get frames going to the end of the whole video.

  In the output the first two images should be discarded and the next 6 images (from 3rd til 8th) will be the ones we were looking for. Most probably there’ll be a 9th image as well which can be discarded too. You can also add the -vframes 8 option (where 8 is number_of_frames + 2) to skip the creation of the last image that you won’t need anyway.

  How accurately are these frames captured ? Because I would like to add timestamps to each frame. (FFProbe is not an option because I am using an Android application and dont want to have to build the binaries just for this).

  If for example I had a video of 14 seconds long and ffmpeg extracted 11 frames (I remove one of the first duplicate ones, so now 10 frames). If i then did videoLength / number of frames * which frame I want to find how accurate would this be ? So :

  14/10 * 1 = 1 so frame one goes from 0s - 1.4s
  
  14/10 * 2 = 2.8 so frame two goes from 1.4s - 2.8s
  
  14/10 * 3 = 4.2 so frame two goes from 2.8s - 4.2s
  
  ...
  
  14/10 * 10 = 14 so frame two goes from 12.6s - 14s

  Would this accurate represent each frame ?

  If not could someonne give me a better solution please thanks.

  The idea is I have created a video cropper with a recyclerview so I will be able to "go over" each frame with a drag tool, calculate how much the frame has been covered and then find what range that frame represents and then set a time for the start and end crop times

• Is there any way to edit just the metadata of an AVI file, like mkvpropedit does with MKV files ?

  20 juillet 2016, par hmj6jmh

  I am trying to swap the order of 2 audio tracks of an AVI file using ffmpeg.

  ffmpeg -i "infile.avi" -map 0:0 -map 0:2 -map 0:1 -c copy "outfile.avi"

  This works but the file is being re-encoded, not copied. It takes much longer than a straight copy to finish and the resulting file is larger than the original.

  Is there any way to edit just the metadata of an AVI file, like mkvpropedit does with MKV files ? Command line tool preferred.

  General
  
  Complete name                            : infile.avi
  
  Format                                   : AVI
  
  Format/Info                              : Audio Video Interleave
  
  File size                                : 451 MiB
  
  Duration                                 : 43mn 11s
  
  Overall bit rate                         : 1 460 Kbps
  
  Writing application                      : VirtualDubMod 1.5.10.2 (build 2540/release)
  
  Writing library                          : VirtualDubMod build 2540/release
  
  
  
  Video
  
  ID                                       : 0
  
  Format                                   : MPEG-4 Visual
  
  Format profile                           : Advanced Simple@L5
  
  Format settings, BVOP                    : 3
  
  Format settings, QPel                    : No
  
  Format settings, GMC                     : No warppoints
  
  Format settings, Matrix                  : Default (MPEG)
  
  Muxing mode                              : Packed bitstream
  
  Codec ID                                 : XVID
  
  Codec ID/Hint                            : XviD
  
  Duration                                 : 43mn 11s
  
  Bit rate                                 : 1 190 Kbps
  
  Width                                    : 656 pixels
  
  Height                                   : 368 pixels
  
  Display aspect ratio                     : 16:9
  
  Frame rate                               : 23.976 fps
  
  Color space                              : YUV
  
  Chroma subsampling                       : 4:2:0
  
  Bit depth                                : 8 bits
  
  Scan type                                : Progressive
  
  Compression mode                         : Lossy
  
  Bits/(Pixel*Frame)                       : 0.206
  
  Stream size                              : 367 MiB (82%)
  
  Writing library                          : XviD 1.2.1 (UTC 2008-12-04)
  
  
  
  Audio #1
  
  ID                                       : 1
  
  Format                                   : MPEG Audio
  
  Format version                           : Version 1
  
  Format profile                           : Layer 3
  
  Codec ID                                 : 55
  
  Codec ID/Hint                            : MP3
  
  Duration                                 : 43mn 11s
  
  Bit rate mode                            : Constant
  
  Bit rate                                 : 128 Kbps
  
  Channel count                            : 2 channels
  
  Sampling rate                            : 48.0 KHz
  
  Compression mode                         : Lossy
  
  Stream size                              : 39.5 MiB (9%)
  
  Alignment                                : Aligned on interleaves
  
  Interleave, duration                     : 42 ms (1.00 video frame)
  
  Interleave, preload duration             : 504 ms
  
  Writing library                          : LAME3.98r
  
  Encoding settings                        : -m s -V 4 -q 2 -lowpass 17 -b 128
  
  
  
  Audio #2
  
  ID                                       : 2
  
  Format                                   : MPEG Audio
  
  Format version                           : Version 1
  
  Format profile                           : Layer 3
  
  Codec ID                                 : 55
  
  Codec ID/Hint                            : MP3
  
  Duration                                 : 43mn 11s
  
  Bit rate mode                            : Constant
  
  Bit rate                                 : 128 Kbps
  
  Channel count                            : 2 channels
  
  Sampling rate                            : 48.0 KHz
  
  Compression mode                         : Lossy
  
  Stream size                              : 39.5 MiB (9%)
  
  Alignment                                : Aligned on interleaves
  
  Interleave, duration                     : 42 ms (1.00 video frame)
  
  Interleave, preload duration             : 504 ms
  
  Writing library                          : LAME3.98r
  
  Encoding settings                        : -m s -V 4 -q 2 -lowpass 17 -b 128

• avcodec : Remove libaacplus

  24 janvier 2016, par Timothy Gu

  avcodec : Remove libaacplus
  TODO : bump minor
  It’s inferior in quality to fdk-aac and has an arguably more problematic
  
  license.
  As early as 2012, a HydrogenAudio user reported :
  > It has however one huge advantage : much better quality at low bitrates than
  
  > faac and libaacplus.
  (https://hydrogenaud.io/index.php?PHPSESSID=ckiq394pdglka0kj2fin6ij8t7&topic=95989.msg804633#msg804633)
  I myself have made a few spectrograms for a comparison of the two
  
  encoders as well. The FDK output is consistently better than the
  
  libaacplus one, in all bitrates I tested.
  libaacplus license is 3GPP + LGPLv2. 3GPP copyright notice is completely
  
  proprietory, as follows :
  > No part may be reproduced except as authorized by written permission.
  
  >
  
  > The copyright and the foregoing restriction extend to reproduction in
  
  > all media.
  
  >
  
  > © 2008, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC).
  
  >
  
  > All rights reserved.
  (The latest 26410-d00 zip from 3GPP has the same notice, but the copyright
  
  year is changed to 2015)
  The copyright part of the FDK AAC license (section 2) is a copyleft
  
  license that permits redistribution under certain conditions (and
  
  therefore the LGPL + libfdk-aac combination is not prohibited by
  
  configure) :
  > Redistribution and use in source and binary forms, with or without
  
  > modification, are permitted without payment of copyright license fees
  
  > provided that you satisfy the following conditions :
  
  >
  
  > You must retain the complete text of this software license in
  
  > redistributions of the FDK AAC Codec or your modifications thereto in
  
  > source code form.
  
  >
  
  > You must retain the complete text of this software license in the
  
  > documentation and/or other materials provided with redistributions of
  
  > the FDK AAC Codec or your modifications thereto in binary form.
  
  >
  
  > You must make available free of charge copies of the complete source
  
  > code of the FDK AAC Codec and your modifications thereto to recipients
  
  > of copies in binary form.
  
  >
  
  > The name of Fraunhofer may not be used to endorse or promote products
  
  > derived from this library without prior written permission.
  
  >
  
  > You may not charge copyright license fees for anyone to use, copy or
  
  > distribute the FDK AAC Codec software or your modifications thereto.
  
  >
  
  > Your modified versions of the FDK AAC Codec must carry prominent
  
  > notices stating that you changed the software and the date of any
  
  > change. For modified versions of the FDK AAC Codec, the term
  
  > "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the
  
  > term "Third-Party Modified Version of the Fraunhofer FDK AAC Codec
  
  > Library for Android."
  

  • [DH] Changelog
  • [DH] LICENSE.md
  • [DH] configure
  • [DH] doc/general.texi
  • [DH] doc/platform.texi
  • [DH] libavcodec/Makefile
  • [DH] libavcodec/allcodecs.c
  • [DH] libavcodec/libaacplus.c