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XMP PHP
13 mai 2011, parDixit Wikipedia, XMP signifie :
Extensible Metadata Platform ou XMP est un format de métadonnées basé sur XML utilisé dans les applications PDF, de photographie et de graphisme. Il a été lancé par Adobe Systems en avril 2001 en étant intégré à la version 5.0 d’Adobe Acrobat.
Étant basé sur XML, il gère un ensemble de tags dynamiques pour l’utilisation dans le cadre du Web sémantique.
XMP permet d’enregistrer sous forme d’un document XML des informations relatives à un fichier : titre, auteur, historique (...) -
Use, discuss, criticize
13 avril 2011, parTalk to people directly involved in MediaSPIP’s development, or to people around you who could use MediaSPIP to share, enhance or develop their creative projects.
The bigger the community, the more MediaSPIP’s potential will be explored and the faster the software will evolve.
A discussion list is available for all exchanges between users. -
Installation en mode ferme
4 février 2011, parLe mode ferme permet d’héberger plusieurs sites de type MediaSPIP en n’installant qu’une seule fois son noyau fonctionnel.
C’est la méthode que nous utilisons sur cette même plateforme.
L’utilisation en mode ferme nécessite de connaïtre un peu le mécanisme de SPIP contrairement à la version standalone qui ne nécessite pas réellement de connaissances spécifique puisque l’espace privé habituel de SPIP n’est plus utilisé.
Dans un premier temps, vous devez avoir installé les mêmes fichiers que l’installation (...)
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Winamp and the March of GUI
Ars Technica recently published a 15-year retrospective on the venerable Winamp multimedia player, prompting bouts of nostalgia and revelations of "Huh ? That program is still around ?" from many readers. I was among them.
I remember first using Winamp in 1997. I remember finding a few of these new files called MP3s online and being able to play the first 20 seconds using the official Fraunhofer Windows player— full playback required the fully licensed version. Then I searched for another player and came up with Winamp. The first version I ever used was v1.05 in the summer of 1997. I remember checking the website often for updates and trying out every single one. I can’t imagine doing that nowadays— programs need to auto-update themselves (which Winamp probably does now ; I can’t recall the last time I used the program).
Video Underdog
The last time Winamp came up on my radar was early in 2003 when a new version came with support for a custom, proprietary multimedia audio/video format called Nullsoft Video (NSV). I remember the timeframe because the date is indicated in the earliest revision of my NSV spec document (back when I was maintaining such docs in a series of plaintext files). This was cobbled together from details I and others in the open source multimedia community sorted out from sample files. It was missing quite a few details, though.Then, Winamp founder Justin Frankel — introduced through a colleague on the xine team — emailed me his official NSV format and told me I was free to incorporate details into my document just as long as it wasn’t obvious that I had the official spec. This put me in an obnoxious position of trying to incorporate details which would have been very difficult to reverse engineer without the official doc. I think I coped with the situation by never really getting around to updating my doc in any meaningful way. Then, one day, the official spec was released to the world anyway, and it is now mirrored here at multimedia.cx.
I don’t think the format ever really caught on in any meaningful way, so not a big deal. (Anytime I say that about a format, I always learn it saw huge adoption is some small but vocal community.)
What’s Wrong With This Picture ?
What I really wanted to discuss in this post was the matter of graphical user interfaces and how they have changed in the last 15 years.
I still remember when I first downloaded Winamp v1.05 and tried it on my Windows machine at the time. Indignantly, the first thought I had was, "What makes this program think it’s so special that it’s allowed to violate the user interface conventions put forth by the rest of the desktop ?" All of the Windows programs followed a standard set of user interface patterns and had a consistent look and feel... and then Winamp came along and felt it could violate all those conventions.I guess I let the program get away with it because it was either that or only play 20-second clips from the unregistered Fraunhofer player. Though incredibly sterile by comparison, the Fraunhofer player, it should be noted, followed Windows UI guidelines to the letter.
As the summer of 1997 progressed and more Winamp versions were released, eventually one came out (I think it was v1.6 or so) that supported skins. I was excited because there was a skin that made the program look like a proper Windows program— at least if you used the default Windows color scheme, and had all of your fonts a certain type and size.
Skins were implemented by packaging together a set of BMP images to overlay on various UI elements. I immediately saw a number of shortcomings with this skinning approach. A big one was UI lock-in. Ironically, if you skin an app and wish to maintain backwards compatibility with the thousands of skins selflessly authored by your vibrant community (seriously, I couldn’t believe how prolific these things were), then you were effectively locked into the primary UI. Forget about adding a new button anywhere.
Another big problem was resolution-independence. Basing your UI on static bitmaps doesn’t scale well with various resolutions. Winamp had its normal mode and it also had double-sized mode.
Skins proliferated among many types of programs in the late 1990s. I always treasured this Suck.com (remember them ? that’s a whole other nostalgia trip) essay from April, 2000 entitled Skin Cancer. Still, Winamp was basically the standard, and the best, and I put away my righteous nerd rage and even dug through the vast troves of skins. I remember settling on Swankamp for a good part of 1998, probably due to the neo-swing revival at the time.
Then again, if Winamp irked me, imagine my reaction when I was first exposed to the Sonique Music Player in 1998 :
The New UI Order
Upon reflection, I realize now that I had a really myopic view of what a computer GUI should be. I thought the GUIs were necessarily supposed to follow the WIMP (windows, icons, mouse, pointer) paradigm and couldn’t conceive of anything different. For a long time, I couldn’t envision a useful GUI on a small device (like a phone) because WIMP didn’t fit well on such a small interface (even though I saw various ill-fated attempts to make it work). This thinking seriously crippled me when I was trying to craft a GUI for a custom console media player I was developing as a hobby many years ago.I’m looking around at what I have open on my Windows 7 desktop right now. Google Chrome browser, Apple iTunes, Adobe Photoshop Elements, and VMware Player are 4 programs which all seem to have their own skins. Maybe Winamp doesn’t look so out of place these days.
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ffmpeg command for faster encoding at a decent bitrate with smaller file size
28 juillet 2023, par Blair HolmesI'm currently using an implementation of ffmpeg on my android app. I'm allowing users to take short videos within my app and then when they upload them to the server, I'm crunching them down with ffmpeg to decrease file size so they're not passing huge amounts of data over the wire.



the problem is, it's taking forever to encode the videos on the android device. These videos usually aren't longer than 45 seconds and can take 20 minutes to encode. I've done some playing around with different switches / parameters on the ffmpeg command line and I now have it at a more comfortable time, but the file sizes are significantly bigger. I'm just not sure what codec I should use (fastest encoding but with decent quality output), how ffmpeg handles changing size (aspect ratio) in terms of speed of encoding etc.



Here are the two commands I've been using. This first one outputs the file size / quality that I want, but it just takes way too long to encode, not to mention it makes my device get really hot while it's encoding for so long :



ffmpeg -i input.mp4 -b:v 1024k -c:a copy -vf scale=960:540 output.mp4




I've tweaked the bitrate some on that as well as changed the scale to a smaller size, but I don't want to have to make the videos really small (in terms of scale) to accomplish a faster encoding. this second command goes a lot faster but makes the file size significantly bigger :



ffmpeg -i input.mp4 -vcodec libx264 -preset fast -c:a copy -s 960x540 output.mp4




I'd like to find a happy medium (smaller file size but faster encoding) keeping the video scale size close to the original. ffmpeg just has so many different parameters / switches that it's difficult to wrap my head around what I should be doing.



EDIT : adding ffmpeg output.



ffmpeg -i input.mp4 -vcodec libx264 -crf 30 -preset veryfast -c:a copy -s 960x540 output.mp4



09-13 11:06:28.330 10881-10881/someapp D/home: ffmpeg version n3.0.1 Copyright (c) 2000-2016 the FFmpeg developers
09-13 11:06:28.330 10881-10881/someapp D/home: built with gcc 4.8 (GCC)
09-13 11:06:28.331 10881-10881/someapp D/home: configuration: --target-os=linux --cross-prefix=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/bin/arm-linux-androideabi- --arch=arm --cpu=cortex-a8 --enable-runtime-cpudetect --sysroot=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/sysroot --enable-pic --enable-libx264 --enable-libass --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-fontconfig --enable-pthreads --disable-debug --disable-ffserver --enable-version3 --enable-hardcoded-tables --disable-ffplay --disable-ffprobe --enable-gpl --enable-yasm --disable-doc --disable-shared --enable-static --pkg-config=/home/vagrant/SourceCode/ffmpeg-android/ffmpeg-pkg-config --prefix=/home/vagrant/SourceCode/ffmpeg-android/build/armeabi-v7a --extra-cflags='-I/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/include -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fno-strict-overflow -fstack-protector-all' --extra-ldflags='-L/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/lib -Wl,-z,relro -Wl,-z,now -pie' --extra-libs='-lpng -lexpat -lm' --extra-cxxflags=
09-13 11:06:28.331 10881-10881/someapp D/home: libavutil 55. 17.103 / 55. 17.103
09-13 11:06:28.331 10881-10881/someapp D/home: libavcodec 57. 24.102 / 57. 24.102
09-13 11:06:28.331 10881-10881/someapp D/home: libavformat 57. 25.100 / 57. 25.100
09-13 11:06:28.331 10881-10881/someapp D/home: libavdevice 57. 0.101 / 57. 0.101
09-13 11:06:28.331 10881-10881/someapp D/home: libavfilter 6. 31.100 / 6. 31.100
09-13 11:06:28.331 10881-10881/someapp D/home: libswscale 4. 0.100 / 4. 0.100
09-13 11:06:28.331 10881-10881/someapp D/home: libswresample 2. 0.101 / 2. 0.101
09-13 11:06:28.331 10881-10881/someapp D/home: libpostproc 54. 0.100 / 54. 0.100
09-13 11:06:28.430 10881-10881/someapp D/home: Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/storage/emulated/0/ExpeditionSpot/Videos/20160913110411.mp4':
09-13 11:06:28.430 10881-10881/someapp D/home: Metadata:
09-13 11:06:28.430 10881-10881/someapp D/home: major_brand : mp42
09-13 11:06:28.430 10881-10881/someapp D/home: minor_version : 0
09-13 11:06:28.430 10881-10881/someapp D/home: compatible_brands: isommp42
09-13 11:06:28.430 10881-10881/someapp D/home: creation_time : 2016-09-13 17:04:33
09-13 11:06:28.430 10881-10881/someapp D/home: com.android.version: 6.0.1
09-13 11:06:28.430 10881-10881/someapp D/home: Duration: 00:00:19.41, start: 0.000000, bitrate: 20222 kb/s
09-13 11:06:28.430 10881-10881/someapp D/home: Stream #0:0(eng): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p, 1920x1080, 19963 kb/s, SAR 1:1 DAR 16:9, 30.03 fps, 30 tbr, 90k tbn, 180k tbc (default)
09-13 11:06:28.430 10881-10881/someapp D/home: Metadata:
09-13 11:06:28.430 10881-10881/someapp D/home: creation_time : 2016-09-13 17:04:33
09-13 11:06:28.430 10881-10881/someapp D/home: handler_name : VideoHandle
09-13 11:06:28.431 10881-10881/someapp D/home: Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 96 kb/s (default)
09-13 11:06:28.431 10881-10881/someapp D/home: Metadata:
09-13 11:06:28.431 10881-10881/someapp D/home: creation_time : 2016-09-13 17:04:33
09-13 11:06:28.431 10881-10881/someapp D/home: handler_name : SoundHandle
09-13 11:06:28.448 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] using SAR=1/1
09-13 11:06:28.448 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] using cpu capabilities: none!
09-13 11:06:28.516 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] profile High, level 3.1
09-13 11:06:28.516 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] 264 - core 148 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1 ref=1 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=12 lookahead_threads=4 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=10 rc=crf mbtree=1 crf=27.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
09-13 11:06:28.532 10881-10881/someapp D/home: Output #0, mp4, to '/storage/emulated/0/ExpeditionSpot/.tmp/small-20160913110411.mp4':
09-13 11:06:28.532 10881-10881/someapp D/home: Metadata:
09-13 11:06:28.532 10881-10881/someapp D/home: major_brand : mp42
09-13 11:06:28.533 10881-10881/someapp D/home: minor_version : 0
09-13 11:06:28.533 10881-10881/someapp D/home: compatible_brands: isommp42
09-13 11:06:28.533 10881-10881/someapp D/home: com.android.version: 6.0.1
09-13 11:06:28.533 10881-10881/someapp D/home: encoder : Lavf57.25.100
09-13 11:06:28.533 10881-10881/someapp D/home: Stream #0:0(eng): Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 960x540 [SAR 1:1 DAR 16:9], q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
09-13 11:06:28.533 10881-10881/someapp D/home: Metadata:
09-13 11:06:28.533 10881-10881/someapp D/home: creation_time : 2016-09-13 17:04:33
09-13 11:06:28.533 10881-10881/someapp D/home: handler_name : VideoHandle
09-13 11:06:28.533 10881-10881/someapp D/home: encoder : Lavc57.24.102 libx264
09-13 11:06:28.533 10881-10881/someapp D/home: Side data:
09-13 11:06:28.533 10881-10881/someapp D/home: unknown side data type 10 (24 bytes)
09-13 11:06:28.533 10881-10881/someapp D/home: Stream #0:1(eng): Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, 96 kb/s (default)
09-13 11:06:28.533 10881-10881/someapp D/home: Metadata:
09-13 11:06:28.533 10881-10881/someapp D/home: creation_time : 2016-09-13 17:04:33
09-13 11:06:28.533 10881-10881/someapp D/home: handler_name : SoundHandle
09-13 11:06:28.533 10881-10881/someapp D/home: Stream mapping:
09-13 11:06:28.533 10881-10881/someapp D/home: Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
09-13 11:06:28.533 10881-10881/someapp D/home: Stream #0:1 -> #0:1 (copy)
09-13 11:06:28.533 10881-10881/someapp D/home: Press [q] to stop, [?] for help
09-13 11:06:29.102 10881-10881/someapp D/home: frame= 7 fps=0.0 q=0.0 size= 0kB time=00:00:01.04 bitrate= 0.4kbits/s speed=2.08x 
09-13 11:06:29.699 10881-10881/someapp D/home: frame= 16 fps= 15 q=0.0 size= 0kB time=00:00:01.04 bitrate= 0.4kbits/s speed=0.998x 
....
09-13 11:07:12.674 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] frame I:3 Avg QP:26.83 size: 21896
09-13 11:07:12.674 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] frame P:279 Avg QP:28.76 size: 5859
09-13 11:07:12.674 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] frame B:296 Avg QP:29.93 size: 863
09-13 11:07:12.674 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] consecutive B-frames: 18.3% 32.2% 23.9% 25.6%
09-13 11:07:12.674 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] mb I I16..4: 16.9% 54.2% 28.9%
09-13 11:07:12.674 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] mb P I16..4: 7.7% 9.1% 0.4% P16..4: 27.5% 11.1% 4.0% 0.0% 0.0% skip:40.1%
09-13 11:07:12.674 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] mb B I16..4: 0.8% 0.6% 0.0% B16..8: 10.9% 2.4% 0.1% direct: 1.8% skip:83.5% L0:35.8% L1:54.2% BI:10.0%
09-13 11:07:12.675 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] 8x8 transform intra:52.0% inter:41.3%
09-13 11:07:12.675 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] coded y,uvDC,uvAC intra: 28.9% 26.0% 2.1% inter: 6.4% 5.0% 0.0%
09-13 11:07:12.675 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] i16 v,h,dc,p: 57% 20% 17% 6%
09-13 11:07:12.675 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 23% 34% 1% 2% 1% 3% 2% 2%
09-13 11:07:12.675 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 36% 21% 17% 2% 7% 4% 6% 4% 4%
09-13 11:07:12.675 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] i8c dc,h,v,p: 59% 16% 23% 2%
09-13 11:07:12.675 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] Weighted P-Frames: Y:16.8% UV:4.7%
09-13 11:07:12.675 10881-10881/someapp D/home: [libx264 @ 0xf71c4400] kb/s:812.09