Recherche avancée

Sur d’autres sites (6111)

• Do FFMPEG H264 compression presets affect the video quality ? [closed]

  14 novembre 2013, par angainor

  I am definitely not an FFMPEG expert, but according to this document :

  A preset is a collection of options that will provide a certain encoding speed to compression ratio. A slower preset will provide better compression (compression is quality per filesize). General usage is to use the slowest preset that you have patience for. Current presets in descending order of speed are : ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, placebo.

  So as I understand it, the ffmpeg presets should not affect the quality of the output video, but should only determine the compression ratio / output file size. Consequently, assuming the same quality setting (I will use -crf 24), the files should be larger for e.g., faster preset than for the slower preset. That would be the only reason to use a slower preset - to get a smaller file size.

  This turns out not to be the case. I encode a HD stream from a handycam using different presets, everything else is the same :

  ffmpeg -y -i "$fname" -vf yadif=1,scale=-1:720 -acodec aac -ab 128k -ac 2 -strict experimental -vcodec libx264 -vpre slow -threads 2 -crf 24 "$outp"

  Surprisingly, I get the smallest file size for veryfast preset ! For example :

  • slower : output bitrate 3500kbps, encoding speed 17 fps, file size 29MB
  • veryfast : output bitrate 3050kbps, encoding speed 34 fps, file size 25MB

  Which I think is not as it should be. Now I wonder, is that due to a worse encoding quality for the veryfast preset ? Or in my case using slower does simply not make sense for some reason ?

• Piwik 1.12, New Features, API Improvements, Stability — The Last Piwik 1.X Release

  30 mai 2013, par Piwik team — Development

  We are very excited to announce the immediate availability of Piwik v1.12 !

  • Download Link
  • How to update Piwik ?
  • List of all tickets closed : Changelog

  Piwik v1.12 is a major new release with four big new features, seven smaller new features, several API improvements and all together 82 tickets fixed. This is also the last major 1.X release, which means after this release we will be working on releasing Piwik 2.0. This also means that you should upgrade to PHP 5.3 or higher if you haven’t already, since Piwik 2.0 will only support PHP 5.3 and above.

  Finally, this release contains two breaking changes to the API. If you use the Piwik API click here or scroll down to see if you’re affected.

  Table of Contents :

  1. New Big Feature – Beta Release Channel
  2. New Big Feature – Segment Editor
  3. New Big Feature – Page Speed Reports
  4. New Big Feature – Device Detection Reports
  5. Other Improvements
  6. API Changes and Improvements
  7. What we’re working on
  8. Participate in Piwik
  9. Summary

  New Big Feature – Beta Release Channel

  

  For those of you who want to help test Piwik 2.0-beta releases as soon as they come up, we’ve made it easier to use our beta releases. Navigate to the Settings > General Settings page and click the The latest beta release radio button. You will then be able to upgrade to beta releases.

  This isn’t truly a major feature, but we think it’s just as important because it will allow us to create more beta releases and thus catch more bugs before we make a final release. This means more releases and more stability for you.

  New Big Feature – Segment Editor

  

  The Segment Editor is a long-awaited new feature that allows you to view, save and edit your segments.

  Piwik has supported segmentation (filtering visits and reports by arbitrary criteria, like browser family) for quite some time now, but it has never been possible to visually create and modify them. Nor could they be saved for later recall.

  Thanks to the eighty individuals and company who funded this feature, it is now possible to :

  • visually segment your visitors, instead of creating URLs.
  • save segments and easily switch between them, instead of remembering URLs.
  • get suggestions for segments that might be helpful to view.
  • learn more in the Segmentating Analytics reports user documentation..

  New Big Feature – Page Speed Reports

  You can now see how long it took your webserver to generate and send pages over HTTP through the new Avg. Generation Time metric.

  This metric can be viewed on both the Pages and Page Titles reports :

  

  And the average page generation time for all the pages in your website/webapp is displayed on the visitors overview :

  

  You can use this new information to benchmark your webapp and web server.

  New Big Feature – Device Detection Reports

  Piwik 1.12 also includes a new plugin that provides reports on the device types (tablet, desktop, smartphone, etc.), device brands (Apple, Google, Samsung, etc.) and device models (iPad, Nexus 7, etc.) your visitors use to access your website :

  

  The new plugin also enhances Operating system detections (detecting sub versions of Linux, Windows, and more).

  Note : This plugin is not enabled by default, but will be in Piwik 2.0. If you want to view these reports now, you can activate the plugin in the Installed Plugins admin page. Navigate to Visitors > Devices to see the new reports. You may also use the new (beta) ‘Device type’.

  The new plugin was developed with the support of Clearcode.cc our technology partner

  

  Other improvements

  Majestic SEO Metrics

  

  We’ve added two new SEO metrics to the SEO widget, both of which are calculated by MajesticSEO.com. These metrics will tell you the number of external backlinks (the number of links to your site from other sites) and the number of referrer domains (the number of domains that link to your site).

  We thank the team at Majestic for their support and hard work in bringing you these metrics to your Piwik dashboards !

  Real-time Visitor Count Dashboard Widget

  

  There is now a simple new widget you can use to see the number of visitors, visits and actions that occurred in the last couple minutes. We call it the Real Time Visitor Counter !

  New segment parameter : siteSearchKeyword.

  There is now a new segment parameter you can use to segment your visits : siteSearchKeyword. This parameter will let you select visits that had site searches with a specific keyword.

  Ignore URL letter case when importing log files.

  We’ve added a new option to the log import script, –force-lowercase-path. When used, the importer will change URL paths to lowercase before tracking them. This way http://domain.com/MY/BLOG will be treated the same as http://domain.com/my/blog.

  Updated ISP Names

  

  We’ve also modified the Providers report so prettier and more up-to-date names of ISPs are displayed.

  Customize the background/text/axis color of graphs.

  

  It is now possible to change the background color, text color and/or axis color of the graph images generated by the ImageGraph plugin. To access this functionality, use the following URL query parameters when generating an image :

  • backgroundColor
  • textColor
  • axisColor

  For example :

  http://demo.piwik.org/index.php?module=API&method=ImageGraph.get&idSite=7&apiModule=UserSettings&apiAction=getBrowser&token_auth=anonymous&period=day&date=2013-03-21,2013-04-19&language=en&width=779&height=150&fontSize=9&showMetricTitle=0&aliasedGraph=1&legendAppendMetric=0&backgroundColor=efefef&gridColor=dcdcdc&colors=cb2026

  Send your users to a custom URL after they logout.

  If you manage a Piwik installation with many users and you want to send them to a custom page or website after they log out of Piwik, you can now specify the URL to redirect users after they log out.

  API Changes and Improvements

  BREAKING CHANGE – renamed segment parameters.

  The following segment parameters have been renamed :

  • continent renamed to : continentCode
  • browserName renamed to : browserCode
  • operatingSystem renamed to : operatingSystemCode
  • lat renamed to : latitude
  • long renamed to : longitude
  • region renamed to : regionCode
  • country renamed to : countryCode
  • continent renamed to : continentCode

  If you use one of the old segment parameter names, Piwik will throw an exception, so you should notice when you’re using an old name.

  BREAKING CHANGE – changes to the input & output of the Live.getLastVisitsDetails method.

  The following changes were made to the Live.getLastVisitsDetails API method :

  • The method no longer uses the maxIdVisit query parameter. It has been replaced by the filter_offset parameter.
  • Site search keywords are now displayed in a <siteSearchKeyword> element. They were formerly in <pageTitle> elements.
  • Custom variables with page scope now have ‘Page’ in their element names when displayed. For example, <customVariablePageName1>, <customVariablePageName2>, etc.

  Filter results of MultiSites.getAll by website name.

  It is now possible to filter the results of MultiSites.getAll by website name. To do this, set the pattern query parameter to the desired regex pattern.

  Get suggested values to use for a segment parameter.

  The new API method API.getSuggestedValuesForSegment can now be used to get suggested values for a segment parameter. This method will return a list of the most seen values (in the last 60 days) for a certain segment parameter. So for browserCode, this would return the codes for the browsers most visitors used in the last 60 days.

  Use extra tracking query parameters with the JS tracker (such as ‘lat’ & ‘long’).

  We’ve added a new method to the JavaScript tracker named appendToTrackingUrl. You can use this method to add extra query parameters to a tracking request, like so :

  _paq.push(['appendToTrackingUrl', 'lat=X&long=Y']);

  What we’re working on

  As we said above, Piwik v1.12 is the last in the 1.X series of releases. This means we are now officially working on Piwik 2.0.

  Piwik 2.0 will be a big release, to be sure, but it’s going to bring you more than just a couple new features and a bag of bug fixes. For Piwik 2.0 we will be revisiting the user needs and the ideals that originally prompted us to create Piwik in order to build our vision of the future of web analytics.

  Piwik 2.0 won’t just be a bigger, better web app, but a new platform for observing and analyzing the things that matter to you.

  Participate in Piwik

  Are you a talented developer or an experienced User Interface designer ? Or maybe you like to write documentation or are a marketing guru ?

  If you have some free time and if you want to contribute to one of the most awesome open source projects around, please get in touch with the Piwik team, or read this page to learn more…

  Summary

  For the full list of changes in Piwik 1.12 check out the Changelog.

  Thank you to the core developers, all the beta testers and users, our official supporters, the translators & everyone who reported bugs or feature requests. Also thank you to softwares we use, and the libraries we use.

  If you are a company and would like to help an important project like Piwik grow, please get in touch, it means a lot to us. You can also participate in the project —

  –> if you like what you read, please tell your friends and colleagues or write on your website, blog, forums, stackoverflow, etc. <–
  

  Peace. Enjoy !

• FFMPEG enocde flv with alpha channel

  25 octobre 2013, par tree

  I'm trying to encode a video (mov) to an flv with alpha channel in FFMPEG but I can't seem to either

  1. find a codec that is supported
  2. find one that actually maintains the alpha

  Does anyone know how to set that up ?

  Thanks,

  ffmpeg -i abc_btr_1280x800_Takeover.mov -vcodec flv -pix_fmt yuv444p -s 1280x800 test4.flv

  here is the report...

  ffmpeg started on 2013-10-25 at 15:47:30
  
  Report written to "ffmpeg-20131025-154730.log"
  
  Command line: 
  
  ffmpeg -i abc_btr_1280x800_Takeover.mov -vcodec flv -pix_fmt yuv444p -s 1280x800     test4.flv -report
  
  ffmpeg version N-57367-g2f31b73 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Oct 23 2013 20:34:17 with gcc 4.8.2 (GCC)
  
    configuration: --disable-static --enable-shared --enable-gpl --enable-version3 --    disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --    enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-    libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --    enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  
    libavutil      52. 47.101 / 52. 47.101
  
    libavcodec     55. 38.101 / 55. 38.101
  
    libavformat    55. 19.104 / 55. 19.104
  
    libavdevice    55.  4.100 / 55.  4.100
  
    libavfilter     3. 89.100 /  3. 89.100
  
    libswscale      2.  5.101 /  2.  5.101
  
    libswresample   0. 17.104 /  0. 17.104
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Splitting the commandline.
  
  Reading option '-i' ... matched as input file with argument     'abc_btr_1280x800_Takeover.mov'.
  
  Reading option '-vcodec' ... matched as option 'vcodec' (force video codec ('copy' to     copy stream)) with argument 'flv'.
  
  Reading option '-pix_fmt' ... matched as option 'pix_fmt' (set pixel format) with argument 'yuv444p'.
  
  Reading option '-s' ... matched as option 's' (set frame size (WxH or abbreviation)) with argument '1280x800'.
  
  Reading option 'test4.flv' ... matched as output file.
  
  Reading option '-report' ... matched as option 'report' (generate a report) with argument '1'.
  
  Finished splitting the commandline.
  
  Parsing a group of options: global .
  
  Applying option report (generate a report) with argument 1.
  
  Successfully parsed a group of options.
  
  Parsing a group of options: input file abc_btr_1280x800_Takeover.mov.
  
  Successfully parsed a group of options.
  
  Opening an input file: abc_btr_1280x800_Takeover.mov.
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] Format mov,mp4,m4a,3gp,3g2,mj2 probed with size=2048 and score=100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] ISO: File Type Major Brand: qt  
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] File position before avformat_find_stream_info() is 281624339
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] All info found
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] File position after avformat_find_stream_info() is 288732
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'abc_btr_1280x800_Takeover.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      creation_time   : 2013-09-22 02:50:18
  
    Duration: 00:00:10.00, start: 0.000000, bitrate: 225299 kb/s
  
      Stream #0:0(eng), 1, 1/24: Video: qtrle (rle  / 0x20656C72), bgra, 1280x800, 225293 kb/s, SAR 1280:1280 DAR 8:5, 24 fps, 24 tbr, 24 tbn, 24 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-09-22 02:50:18
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
      Stream #0:1(eng), 0, 1/24: Data: none (tmcd / 0x64636D74), 0 kb/s (default)
  
      Metadata:
  
        creation_time   : 2013-09-22 02:50:22
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
  Successfully opened the file.
  
  Parsing a group of options: output file test4.flv.
  
  Applying option vcodec (force video codec ('copy' to copy stream)) with argument flv.
  
  Applying option pix_fmt (set pixel format) with argument yuv444p.
  
  Applying option s (set frame size (WxH or abbreviation)) with argument 1280x800.
  
  Successfully parsed a group of options.
  
  Opening an output file: test4.flv.
  
  Successfully opened the file.
  
  detected 4 logical cores
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'video_size' to value '1280x800'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'pix_fmt' to value '30'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'time_base' to value '1/24'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'pixel_aspect' to value '1280/1280'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'sws_param' to value 'flags=2'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'frame_rate' to value '24/1'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] w:1280 h:800 pixfmt:bgra tb:1/24 fr:24/1 sar:1/1 sws_param:flags=2
  
  [scaler for output stream 0:0 @ 00000000003056a0] Setting 'w' to value '1280'
  
  [scaler for output stream 0:0 @ 00000000003056a0] Setting 'h' to value '800'
  
  [scaler for output stream 0:0 @ 00000000003056a0] Setting 'flags' to value '0x4'
  
  [scaler for output stream 0:0 @ 00000000003056a0] w:1280 h:800 flags:'0x4' interl:0
  
  Incompatible pixel format 'yuv444p' for codec 'flv', auto-selecting format 'yuv420p'
  
  [format @ 00000000002f8320] compat: called with args=[yuv420p]
  
  [format @ 00000000002f8320] Setting 'pix_fmts' to value 'yuv420p'
  
  [AVFilterGraph @ 000000000085bc60] query_formats: 5 queried, 4 merged, 0 already done, 0 delayed
  
  [scaler for output stream 0:0 @ 00000000003056a0] w:1280 h:800 fmt:bgra sar:1/1 -> w:1280 h:800 fmt:yuv420p sar:1/1 flags:0x4
  
  [flv @ 0000000000374be0] intra_quant_bias = 0 inter_quant_bias = -64
  
  Output #0, flv, to 'test4.flv':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      encoder         : Lavf55.19.104
  
      Stream #0:0(eng), 0, 1/1000: Video: flv1 (flv) ([2][0][0][0] / 0x0002), yuv420p,             1280x800 [SAR 1:1 DAR 8:5], q=2-31, 200 kb/s, 1k tbn, 24 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-09-22 02:50:18
  
            handler_name    : Apple Alias Data Handler
  
            timecode        : 00:00:00:00        
  
      Stream mapping:
  
        Stream #0:0 -> #0:0 (qtrle -> flv)
  
  Press [q] to stop, [?] for help
  
  frame=   27 fps=0.0 q=31.0 size=     351kB time=00:00:01.12 bitrate=2554.2kbits/s    
  
  frame=   46 fps= 45 q=31.0 size=     477kB time=00:00:01.91 bitrate=2039.5kbits/s    
  
  frame=   60 fps= 39 q=31.0 size=     543kB time=00:00:02.50 bitrate=1779.4kbits/s    
  
  frame=   74 fps= 36 q=31.0 size=     629kB time=00:00:03.08 bitrate=1672.4kbits/s    
  
  frame=   96 fps= 37 q=31.0 size=     795kB time=00:00:04.00 bitrate=1627.4kbits/s    
  
  frame=  123 fps= 40 q=31.0 size=     924kB time=00:00:05.12 bitrate=1477.0kbits/s    
  
  frame=  149 fps= 41 q=31.0 size=    1133kB time=00:00:06.20 bitrate=1494.7kbits/s    
  
  frame=  175 fps= 43 q=31.0 size=    1224kB time=00:00:07.29 bitrate=1375.5kbits/s    
  
  frame=  201 fps= 44 q=31.0 size=    1352kB time=00:00:08.37 bitrate=1322.7kbits/s    
  
  frame=  228 fps= 45 q=31.0 size=    1461kB time=00:00:09.50 bitrate=1260.1kbits/s    
  
  [output stream 0:0 @ 00000000003053c0] EOF on sink link output stream 0:0:default.
  
  No more output streams to write to, finishing.
  
  frame=  240 fps= 45 q=31.0 Lsize=    1600kB time=00:00:10.00 bitrate=1310.4kbits/s    
  
  
  
  video:1596kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.252476%
  
  240 frames successfully decoded, 0 decoding errors
  
  [AVIOContext @ 000000000032dfc0] Statistics: 3 seeks, 242 writeouts
  
  [AVIOContext @ 000000000085bde0] Statistics: 281664506 bytes read, 3 seeks