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• FFmpeg concat creating corrupted video part (Media Info provided)

  6 mai 2022, par krv

  I am using concat to join a list of video files with the following command

  


  ffmpeg -f concat -safe 0 -i filesList.txt -c copy output.mp4 


  


  The issue here is that there are a few files that were recorded in slow motion on my phone. The slow-motion files have the same frame rate as the other files.

  


  But when concatenated the part where the slow-motion files are concatenated appears to be frozen / glitch (it does not play a single frame).

  


  I am able to seek forward and backward the part that does not play. So the portion of the video that contained normal files plays and as soon as the slow-motion video comes, nothing plays, and when a normal file comes it starts playing again.

  


  I am attaching the media Info of both files

  


  Info of the slow motion file :

  


  General
Complete name :     I:\concate Test\VID20210727114100.mp4
Format :    MPEG-4
Format profile :    Base Media / Version 2
Codec ID :  mp42 (isom/mp42)
File size :     27.6 MiB
Duration :  1 min 0 s
Overall bit rate :  3 825 kb/s
Encoded date :  UTC 2021-07-27 06:11:08
Tagged date :   UTC 2021-07-27 06:11:08
xyz :   +21.6146+071.2342/
com.android.version :   11

Video
ID :    1
Format :    HEVC
Format/Info :   High Efficiency Video Coding
Format profile :    Main@L3.1@Main
Codec ID :  hvc1
Codec ID/Info :     High Efficiency Video Coding
Duration :  1 min 0 s
Source duration :   1 min 0 s
Bit rate :  3 771 kb/s
Width :     1 280 pixels
Height :    720 pixels
Display aspect ratio :  16:9
Frame rate mode :   Variable
Frame rate :    30.000 FPS
Minimum frame rate :    29.910 FPS
Maximum frame rate :    30.090 FPS
Real frame rate :   240.000 FPS
Color space :   YUV
Chroma subsampling :    4:2:0
Bit depth :     8 bits
Bits/(Pixel*Frame) :    0.136
Stream size :   27.2 MiB (99%)
Source stream size :    27.2 MiB (99%)
Title :     VideoHandle
Language :  English
Encoded date :  UTC 2021-07-27 06:11:08
Tagged date :   UTC 2021-07-27 06:11:08
Color range :   Limited
Color primaries :   BT.709
Transfer characteristics :  BT.709
Matrix coefficients :   BT.709
mdhd_Duration :     60524
Codec configuration box :   hvcC


  


  Info of the regular video file

  


  
General
Complete name :     I:\concate Test\VID20210727113901.mp4
Format :    MPEG-4
Format profile :    Base Media / Version 2
Codec ID :  mp42 (isom/mp42)
File size :     39.0 MiB
Duration :  37 s 930 ms
Overall bit rate :  8 615 kb/s
Encoded date :  UTC 2021-07-27 06:09:40
Tagged date :   UTC 2021-07-27 06:09:40
xyz :   +21.6146+071.2342/
com.android.version :   11

Video
ID :    1
Format :    HEVC
Format/Info :   High Efficiency Video Coding
Format profile :    Main@L4@Main
Codec ID :  hvc1
Codec ID/Info :     High Efficiency Video Coding
Duration :  37 s 930 ms
Source duration :   37 s 900 ms
Bit rate :  8 408 kb/s
Width :     1 920 pixels
Height :    1 080 pixels
Display aspect ratio :  16:9
Frame rate mode :   Variable
Frame rate :    29.604 FPS
Minimum frame rate :    29.508 FPS
Maximum frame rate :    29.605 FPS
Real frame rate :   30.000 FPS
Color space :   YUV
Chroma subsampling :    4:2:0
Bit depth :     8 bits
Bits/(Pixel*Frame) :    0.137
Stream size :   38.0 MiB (98%)
Source stream size :    38.0 MiB (98%)
Title :     VideoHandle
Language :  English
Encoded date :  UTC 2021-07-27 06:09:40
Tagged date :   UTC 2021-07-27 06:09:40
Color range :   Limited
Color primaries :   BT.709
Transfer characteristics :  BT.709
Matrix coefficients :   BT.709
mdhd_Duration :     37930
Codec configuration box :   hvcC

Audio
ID :    2
Format :    AAC LC
Format/Info :   Advanced Audio Codec Low Complexity
Codec ID :  mp4a-40-2
Duration :  37 s 909 ms
Bit rate mode :     Constant
Bit rate :  128 kb/s
Channel(s) :    2 channels
Channel layout :    L R
Sampling rate :     48.0 kHz
Frame rate :    46.875 FPS (1024 SPF)
Compression mode :  Lossy
Stream size :   592 KiB (1%)
Title :     SoundHandle
Language :  English
Encoded date :  UTC 2021-07-27 06:09:40
Tagged date :   UTC 2021-07-27 06:09:40




  


• ISO-9660 Compromise, Part 2 : Finding Root

  25 octobre 2021, par Multimedia Mike — General

  A long time ago, I dashed off a quick blog post with a curious finding after studying the ISO-9660 spec : The format stores multi-byte numbers in a format I termed “omni-endian”– the committee developing the format apparently couldn’t come to an agreement on this basic point regarding big- vs. little-endian encoding (I’m envisioning something along the lines of “tastes great ! … less filling !” in the committee meetings).

  I recently discovered another bit of compromise in the ISO-9660 spec : It seems that there are 2 different methods for processing the directory structure. That means it’s incumbent upon ISO-9660 creation software to fill in the data structures to support both methods, because some ISO-reading programs out there rely on one set of data structures while the rest prefer to read the other set.

  Background

  As a refresher, the “ISO” extension of an ISO file refers to the ISO-9660 specification. This is a type of read-only filesystem (i.e, the filesystem is created once and never updated after initial creation) for the purpose of storing on a read-only medium, often an optical disc (CD-ROM, DVD-ROM). The level of nostalgic interest I display for the ISO-9660 filesystem reminds me of my computer science curriculum professors from the mid-90s reminiscing about ye olden days of punchcard programming, but such is my lot. I’m probably also alone in my frustration of seeing rips of, e.g., GameCube or Xbox or 3DO games being tagged with the extension .ISO since those systems use different read-only filesystems.

  I recently fell in with an odd bunch called the eXoDOS project and was trying to help fill in a few gaps. One request was a 1994 game called Power Drive for DOS.

  
  
  

  
  

  My usual CD-ROM ripping method (for the data track) is a simple ‘dd’ command from a Linux command line to copy the string of raw sectors. However, it turned out to be unusually difficult to open the resulting ISO. A few of the the options I know of worked but most didn’t. What’s the difference ?

  Methods that work :

  • Mounting the file with the Linux iso9660 kernel module, i.e.,

    mount -t iso9660 /dev/optical-drive /mnt

    or

    mount -t iso9660 -o loop /path/to/Power-Drive.iso /mnt

  • Directory Opus
  • Windows 10 can read the filesystem when reading the physical disc
  • Windows 10 can burn the ISO image to a new CD (“right click” -> “Burn disc image”) ; this method does not modify any of the existing sectors but did append 149 additional empty sectors

  Methods that don’t work :

  • fuseiso
  • Dosbox
  • Winrar
  • 7zip
  • Daemon Tools
  • Imgburn
  • Internet Archive’s ISO lister (“View contents” on the ISO file)

  Understanding The Difference

  I think I might have a handle on why some tools are able to process this disc while most can’t. There appears to be 2 sets of data structures to describe the base of the filesystem : A root directory, and a path table. These both occur in the first substantive sector of the ISO-9660 filesystem, usually sector 16.

  A compact disc can be abstractly visualized as a long string of sectors, each one 2,352 bytes long. (See my Grand Unified Theory of Compact Disc post for deeper discussion.) A CD-ROM data track will contain 2048 bytes of data. Thus, sector 16 appears at 0x8000 of an ISO filesystem. I like the clarity of this description of the ISO-9660 spec. It shows that the path table is defined at byte 140 (little-endian ; big comes later) and location of the root directory is at byte 158. Thus, these locations generally occur at 0x808c and 0x809e.

  
  
  Primary Volume Descriptor
  

  The path table is highlighted in green and the root directory record is highlighted in red. These absolute locations are specified in sectors. So the path table is located at sector 0x12 = offset 0x9000 in the image, while the root directory record is supposed to be at sector 0x62 = 0x31000. Checking into those sectors, it turns out that the path table is valid while the root directory record is invalid. Thus, any tool that relies on the path table will be successful in interpreting the disc, while tools that attempt to recursively traverse starting from root directory record are gonna have a bad time.

  Since I was able to view the filesystem with a few different tools, I know what the root directory contains. Searching for those filenames reveals that the root directory was supposed to point to the next sector, number 0x63. So this was a bizarre off-by-1 error on the part of the ISO creation tool. Maybe. I manually corrected 0x62 -> 0x63 and that fixed the interaction with fuseiso, but not with other tools. So there may have been some other errors. Note that a quick spot-check of another, functional ISO revealed that this root directory sector is supposed to be exact, not 1-indexed.

  Upon further inspection, I noticed that, while fuseiso appeared to work with that one patch, none of the files returned correct data, and none of the directories contained anything. That’s when I noticed that ALL of the sector locations described in the various directory and file records are off by 1 !

  Further Investigation

  I have occasionally run across ISO images on the Internet Archive that return the error about not being able to read the contents when trying to “View contents” (error text : “failed to obtain file list from xyz.iso”, as seen with this ISO). Too bad I didn’t make a record of them because I would be interested to see if they have the same corruption.

  Eventually, I’ll probably be able to compile an archive of deviant ISO-9660 images. A few months ago, I was processing a large collection from IA and found a corrupted ISO which had a cycle, i.e., the subdirectory pointed to a parent directory, which caused various ISO tools to loop forever. Just one of those things that is “never supposed to happen”, so why write code to deal with it gracefully ?

  See Also

  • The disc archived at The Internet Archive
  • MobyGames Entry
  • Wikipedia Entry

  The post ISO-9660 Compromise, Part 2 : Finding Root first appeared on Breaking Eggs And Making Omelettes.

• How Media Analytics for Piwik gives you the insights you need to measure how effective your video and audio marketing is – Part 1

  31 janvier 2017, par InnoCraft — Community

  Do you have video or audio content on your website or in your app ? If you answered this with yes, you should continue reading and learn everything about our Media Analytics premium feature.

  When you produce video or audio content, you are either spending money or time or often both money and time on your content in the hope of increasing conversions or sales. This means you have to know how your media is being used, when it is used, for how long and by whom. You can simply not afford not to know how this content affects your overall business goals as you are likely losing money and time by not making the most out of it. Would you be able to answer any of the above questions ? Do you know whether you can justify the cost and time for producing them, which videos work better than others and how they support your marketing strategy ? Luckily, getting all these insights is now so trivial it is almost a crime to not measure it.

  Getting Media Analytics and Installation

  Media Analytics can be purchased from the Piwik Marketplace where you find all sorts of free plugins as well as several premium features such as A/B Testing or Funnel. After the purchase you will receive a license key that you can enter in your Piwik to install and update the plugin with just one click.

  The feature will in most cases automatically start tracking your media content and you don’t even need to change the tracking code on your website. Currently supported players are for example YouTube, Vimeo, HTML 5, JW Player, VideoJS and many more players. You can also easily extend it by adding a custom media player or simply by letting us know which player you use and we will add support for it for you.

  By activating this feature, you get more than 15 new media reports, even more exportable widgets, new segments, APIs, and more. We will cover some of those features in this blog post and in part 2. For a full list of features check out the Media Analytics page on the Piwik Marketplace.

  Media Overview

  As the name says, it gives you an overview over your media usage and how it performs over time. You can choose any media metrics in the big evolution graph and the sparklines below give you an overview over all important metrics in a glance.

  

  It lets you for example see how often media was shown to your users, how often users start playing your media, for how long they watched it, how often they finished it, and more. If you see some spikes there, you should definitely have a deeper look at the other reports. When you hover a metric, it will show you a tooltip explaining how the data for this is collected and what it means.

  Real-Time Media

  On the Real-Time page you can see how your content is being used by your visitors right now, for example within the last 30 minutes, last 60 minutes and last 24 hours.

  It shows you how many plays you had in the last minutes, for how long they played it, and it shows you currently most popular media titles. This is great to discover which media content performs best right now and lets you make decisions based on user behaviour that is happening right now.

  

  Below you can see our Audience Real-Time Map that shows you from where in the world your media is being played. A bigger circle indicates that a media play happened more recently and of course you can zoom in down to countries and regions.

  

  All the reports update every few seconds so you can always have a look at it and see in just a second how your content is doing and how certain marketing campaigns affect it. All these real-time reports can be also added as widgets to any of your Piwik Dashboards and they can be exported for example as an iframe.

  Video, Audio and Media Player reports

  Those reports come with so many features, we need a separate blog post and cover this in part 2.

  Events

  Media Analytics will automatically track events so you can see how often users pressed for example play or pause, how often they resumed a video and how often they finished a video. This helps you better understand how your media is being used.

  

  For example in the past we noticed a couple of videos with lots of pause and resume events. We then had a look at the Audience Log – which we will cover next – to better understand why visitors paused the videos so often. We then realized they did this especially for videos that were served from a specific server and because the videos were loading so slow, users often pressed pause to let the media buffer, then played the media for a few seconds and then paused it again as they had to wait for the video to load. Moving those videos to another, faster server showed us immediate results in the number of pauses going down and on average visitors watched the videos for much longer.

  Audience Log

  At InnoCraft, we understand that not only aggregated metrics matter but also that you often need the ability to dig into your data and “debug” certain behaviours to understand the cause for some unusual high or low metrics. For example you may find out that many of your users often pause a video, then you wonder how each individual user behaved so you can better understand the why.

  

  The audience log shows you a detailed log of every visitor. You can chronologically see every action a visitor has performed during their whole visit. If you click on the visitor profile link, you can even see all visits of a specific visitor, and all actions they have ever performed on your website.

  This lets you ultimately debug and understand your visitors and see exactly which actions they performed before playing your media, which media they played, how they played your media, and how they behaved after playing your media.

  The visitor log of course also shows important information about each visitor like where they came from (referrer), their location, software, device and much more information.

  Audience Map

  The Audience Map is similar to the Real-Time Map but it shows you the locations of your visitors based on a selected date range and not in real time. The darker the blue, the more visitors from that country, region or city have interacted with your media.

  

  Coming in part 2

  In the next part we will cover which video, audio and media player reports Media Analytics provides, how segmenting gives you insights into different personas, and how nicely it integrates into Piwik.

  How to get Media Analytics and related features

  You can get Media Analytics on the Piwik Marketplace. If you want to learn more about this feature, you might be also interested in the Media Analytics User Guide and the Media Analytics FAQ.