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• Why FFmpeg transcode with strips

  15 septembre 2023, par Андрей Тернити

  I have MJPEG video. I want get VP9 webm video.

  


  ffmpeg -loglevel verbose -i "input.yuvj422p" -pix_fmt yuv420p -c:v libvpx-vp9 -crf 20 -b:v 0 constantQualityExample.webm


  


  And it works ok (right image), log :

  


  [mjpeg @ 0x55b9b4b7ea40] Format mjpeg detected only with low score of 25, misdetection possible!
Input #0, mjpeg, from 'input.yuvj422p':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: mjpeg (Baseline), 1 reference frame, yuvj422p(pc, bt470bg/unknown/unknown, center), 1280x720 [SAR 1:1 DAR 16:9], 25 tbr, 1200k tbn, 25 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg (native) -> vp9 (libvpx-vp9))
Press [q] to stop, [?] for help
[graph 0 input from stream 0:0 @ 0x55b9b4ba4a00] w:1280 h:720 pixfmt:yuvj422p tb:1/1200000 fr:25/1 sar:1/1
[auto_scaler_0 @ 0x55b9b4ba7c00] w:iw h:ih flags:'bicubic' interl:0
[format @ 0x55b9b4ba5800] auto-inserting filter 'auto_scaler_0' between the filter 'Parsed_null_0' and the filter 'format'
[swscaler @ 0x55b9b4ba8b00] deprecated pixel format used, make sure you did set range correctly
[auto_scaler_0 @ 0x55b9b4ba7c00] w:1280 h:720 fmt:yuvj422p sar:1/1 -> w:1280 h:720 fmt:yuv420p sar:1/1 flags:0x4
[libvpx-vp9 @ 0x55b9b4b85840] v1.7.0
[libvpx-vp9 @ 0x55b9b4b85840] --prefix=/usr --enable-pic --enable-shared --disable-install-bins --disable-install-srcs --size-limit=16384x16384 --enable-postproc --enable-multi-res-encoding --enable-temporal-denoising --enable-vp9-temporal-denoising --enable-vp9-postproc --target=x86_64-linux-gcc
Output #0, webm, to 'constantQualityExample.webm':
  Metadata:
    encoder         : Lavf58.45.100
    Stream #0:0: Video: vp9 (libvpx-vp9), 1 reference frame, yuv420p(center), 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 1k tbn, 25 tbc
    Metadata:
      encoder         : Lavc58.91.100 libvpx-vp9
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
No more output streams to write to, finishing.
Automatically inserted bitstream filter 'vp9_superframe'; args=''


  


  But I want the same by libav. I take official example and make a little changes to make code easy (remove audio capabilities, remove multi-video streams capabilities), my code here. But it produce video with strips and drop last frame (left image).

Mediainfo :

My example log :

  


  Input #0, jpeg_pipe, from 'input.yuvj422p':
  Duration: N/A, bitrate: N/A
  Stream #0:0: Video: mjpeg (Baseline), yuvj422p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 25 tbn
[libvpx-vp9 @ 0x5593e186fa80] v1.11.0
Output #0, webm, to 'VideoOut.webm':
  Stream #0:0: Video: vp9, yuv420p(unknown/bt470bg/unknown), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 25 tbn
[swscaler @ 0x5593e221af00] deprecated pixel format used, make sure you did set range correctly


  


  What I should change in my code to take ok result like ffmpeg ?

  


• Mobile Analytics SDK : beta release of Piwik iOS SDK

  30 octobre 2013, par Piwik team

  Mattias Levin, a Mobile developer enthusiast from Sweden, has released the first public beta version of the official Piwik SDK for iOS !

  If you are building apps for iOS or OSX, you will be able to track your App usage with Piwik. Learn more in this blog post.

  Apps & Mobile apps Analytics

  Using Piwik to track your app usage would give interesting statistics usage such as :

  • number of active users (per day, week, month, …) of my mobile or desktop app,
  • how long users spend in the app,
  • track which icons, buttons are clicked (or any other custom event),
  • record device info, operating system,
  • reports on any Custom Variables you that are relevant to your app (see examples below),
  • how often is the app opened ? When and how long is the app opened ?
  • number of new users, active users, total users,
  • record errors or exception thrown

  Piwik SDK for iOS
  

  The PiwikTracker is an Objective-C framework (for iOS and OSX) designed to send app usage data to a Piwik analytics server. It is realeased under MIT license. Piwik server is a downloadable, Free/Libre (GPLv3 licensed) real time analytics platform.

  Getting started

  1. Create a new website in the Piwik web interface called “My App”. Copy the Website ID and the token_auth.
  2. Download the PiwikTracker SDK.
  3. Add the PiwikTracker files to your project.
  4. Create and configure the PiwikTracker.
  5. Add code in your app to track screen views, events, exceptions, goals and more
  6. Let the dispatch timer dispatch pending events to the Piwik server, or dispatch events manually.

  For more info, check out the Readme.

  Requirements

  The latest PiwikTracker version uses ARC and support iOS6+ and OSX 10.7+.

  • iOS tracker depends on : Core Data, Core Location, Core Graphics, UIKit and AFNetworking.
  • OSX tracker depends on : Core Data, Core Graphics, Cocoa and AFNetworking.

  Demo project

  The workspace contains an iPhone demo app that uses and demonstrates the features available in the SDK.

  

  Feedback needed

  If you use the iOS SDK to track your app, we would like to hear your suggestions, bug reports or general feedback.

  We hope to work with you to improve the SDK and move it out of beta !

  Please report suggestions, bugs, feature requests in the Github Issues at Piwik iOS SDK.

  Happy App Analytics !

• Chrome struggles to play videos

  11 décembre 2017, par Cameron

  I have some video files I want to display on a webpage using the HTML5 video player. The videos were sent to me at 1920x1080 in H.254 MP4 format.

  Using FFMPEG I have converted them so I have a smaller Mp4 file, an OGV file, and a WebM file using the following commands :

  ffmpeg -i FILE.mp4 -vcodec h264 FILE.mp4
  
  
  
  ffmpeg -i FILE.mp4 -acodec libvorbis -vcodec libtheora -f ogv FILE.ogv
  
  
  
  ffmpeg -i FILE.mp4 -c:v libvpx -crf 10 -b:v 1M -c:a libvorbis FILE.webm

  And then the video is embedded into the page like so :

  <video preload="metadata" crossorigin="anonymous" poster="poster.jpg" controls="controls" playsinline="playsinline">
  
      <source src="FILE.webm" type="video/webm">
  
      <source src="FILE.ogv" type="video/ogv">
  
      <source src="FILE.mp4" type="video/mp4">
  
  </source></source></source></video>

  However when I click to play the video in Chrome, it stops after a few seconds and then if I click play again it restarts. If I right click and open the video in a new tab I just see a tiny player and not the video e.g.
  

  The same happens for all three formats. But if I refresh the browser enough times I can get the MP4 file to show up in the new tab though it still suffers from the aforementioned bug of playing for a few seconds before failing.

  I have tested this in Firefox and Safari and it works fine ! In fact it even works in IE and Edge :D And I can also play the videos in a player on the machine itself... e.g. QuickTime.

  Any ideas why Chrome is acting this way ? Or any resolutions ? I’m seeing the same behaviour on Chrome for Windows and Mac. Is the way I have converted the videos using FFMPEG in anyway a cause that could affect Chrome but not other browsers ?

  Chrome version tested on : Version 63.0.3239.84 (Official Build) (64-bit)

  Output from ffprobe as per the comments on the one of the webm files :

  ffprobe version 3.4 Copyright (c) 2007-2017 the FFmpeg developers
  
    built with Apple LLVM version 7.3.0 (clang-703.0.31)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-ffplay --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --enable-openssl --disable-lzma --enable-libopenjpeg --disable-decoder=jpeg2000 --extra-cflags=-I/usr/local/Cellar/openjpeg/2.3.0/include/openjpeg-2.3 --enable-nonfree
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libavresample   3.  7.  0 /  3.  7.  0
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  Input #0, matroska,webm, from 'FILE.webm':
  
    Metadata:
  
      COMPATIBLE_BRANDS: mp42mp41
  
      MAJOR_BRAND     : mp42
  
      MINOR_VERSION   : 0
  
      ENCODER         : Lavf57.83.100
  
    Duration: 00:00:52.57, start: 0.000000, bitrate: 910 kb/s
  
      Stream #0:0(eng): Video: vp8, yuv420p(progressive), 1920x1080, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        HANDLER_NAME    : Alias Data Handler
  
        ENCODER         : Lavc57.107.100 libvpx
  
        DURATION        : 00:00:52.563000000
  
      Stream #0:1(eng): Audio: vorbis, 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        HANDLER_NAME    : Alias Data Handler
  
        ENCODER         : Lavc57.107.100 libvorbis
  
        DURATION        : 00:00:52.568000000