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• Regex problem in Java in code sample

  - by JaneNY

  I have job with regex in my expressions: example !(FA1_A.i & FA1_M.i) I have operators ! ( ) & | operands have names [a-zA-Z_]*.[a-zA-Z_] I wrote in Java to split on tokens, but it doesn't split on operators and operands If should be !, (, FA1_A.i, &, FA1_m.i, ) . Can anybody tell me what is wrong ? String stringOpеrator = "([!|&()])"; String stringOperand = "(([a-zA-Z_]*)\\.([a-zA-Z_]*))"; String reg=stringOpеrator+"|"+stringOperand; Pattern pattern = Pattern.compile(reg); Matcher m = pattern.matcher(expression); // System.out.println("func: " + function + " item: " + item); while (m.find()) { int a=m.start(); int b=m.end(); String test=expression.substring(m.start(), m.end()); String g=test; tokens.add(new Token(expression.substring(m.start() , m.end()))); //m = pattern.matcher(expression); }

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• How to install PHP, Pear, PECL, and APC with Homebrew on Mac OS X?

  - by Andrew

  I'm trying to install APC for PHP 5.3 in the easiest way possible. I love Homebrew so I started down that route. I was able to install PHP 5.3.6 with this command: brew install https://github.com/adamv/homebrew-alt/raw/master/duplicates/php.rb --with-mysql I think this is supposed to install PHP, Pear, and PECL. It seems to install these just fine. Now when I try to install APC: $ pecl install apc downloading APC-3.1.9.tgz ... Starting to download APC-3.1.9.tgz (155,540 bytes) .................................done: 155,540 bytes Warning: require_once(Archive/Tar.php): failed to open stream: No such file or directory in PackageFile.php on line 305 Warning: require_once(Archive/Tar.php): failed to open stream: No such file or directory in /usr/local/Cellar/php/5.3.6/lib/php/PEAR/PackageFile.php on line 305 Fatal error: require_once(): Failed opening required 'Archive/Tar.php' (include_path='/usr/local/Cellar/php/5.3.6/lib/php') in /usr/local/Cellar/php/5.3.6/lib/php/PEAR/PackageFile.php on line 305 How can I fix this?

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• VIDEO Streaming - How to output the video timestamp?

  - by Emmanuel Brunet

  I would like to backup an ASF video stream with the time stamp (I mean the original recording date/time) on the output stream ? Usage I convert / store my video using the mkv format (Matroska) with libx264 (video) and aac (audio) codecs. Assume the IP camera webcam user account is account, the password password $ ffmpeg -i http://admin:alpha1237@webcam/videostream.asf -c:v libx264 -s 768X432 -crf 13 -b:v 2500K -pix_fmt yuv420p -c:a libfdk_aac output.mkv This works fine on a tenvis JPT3815W camera How to I need to get the video timestamp available for display as a subtitle or other meta data field managed by standard video players, and ideally to be able to hide it or not during video reading. Does anybody knows how to achieve that ? Thanks in advance for your help.

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• Where are the real risks in network security?

  - by Barry Brown

  Anytime a username/password authentication is used, the common wisdom is to protect the transport of that data using encryption (SSL, HTTPS, etc). But that leaves the end points potentially vulnerable. Realistically, which is at greater risk of intrusion? Transport layer: Compromised via wireless packet sniffing, malicious wiretapping, etc. Transport devices: Risks include ISPs and Internet backbone operators sniffing data. End-user device: Vulnerable to spyware, key loggers, shoulder surfing, and so forth. Remote server: Many uncontrollable vulnerabilities including malicious operators, break-ins resulting in stolen data, physically heisting servers, backups kept in insecure places, and much more. My gut reaction is that although the transport layer is relatively easy to protect via SSL, the risks in the other areas are much, much greater, especially at the end points. For example, at home my computer connects directly to my router; from there it goes straight to my ISPs routers and onto the Internet. I would estimate the risks at the transport level (both software and hardware) at low to non-existant. But what security does the server I'm connected to have? Have they been hacked into? Is the operator collecting usernames and passwords, knowing that most people use the same information at other websites? Likewise, has my computer been compromised by malware? Those seem like much greater risks. What do you think?

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• Can I compare a template variable to an integer in App Engine templates?

  - by matt b

  Using Django templates in Google App Engine (on Python), is it possible to compare a template variable to an integer in an {% if %} block? views.py: class MyHandler(webapp.RequestHandler): def get(self): foo_list = db.GqlQuery(...) ... template_values['foos'] = foo_list template_values['foo_count'] = len(foo_list) handler.response.out.write(template.render(...)) My template: {% if foo_count == 1 %} There is one foo. {% endif %} This blows up with 'if' statement improperly formatted. What I was attempting to do in my template was build a simple if/elif/else tree to be grammatically correct to be able to state #foo_count == 0: There are no foos. #foo_count == 1: There is one foo. #else: There are {{ foos|length }} foos. Browsing the Django template documents (this link provided in the GAE documentation appears to be for versions of Django far newer than what is supported on GAE), it appears as if I can only actually use boolean operators (if in fact boolean operators are supported in this older version of Django) with strings or other template variables. Is it not possible to compare variables to integers or non-strings with Django templates? I'm sure there is an easy way to workaround this - built up the message string on the Python side rather than within the template - but this seems like such a simple operation you ought to be able to handle in a template. It sounds like I should be switching to a more advanced templating engine, but as I am new to Django (templates or any part of it), I'd just like some confirmation first.

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• Share a USB sound card over a network/bluetooth (Mac & PC)

  - by AlexW

  I've been wondering how I can stream audio to an external Edirol USB sound card, wirelessly, on both Mac and PC. I'm not looking for high quality transmission, just to play mp3s from my Mac laptop to a USB sound card that is attached to two very nice balanced studio reference monitors. Is there any way I can firstly power the sound card box, and secondly, provide with an audio stream along it's USB input. I've looked at the Belkin USB hub, and I have a Time Capsule with the AirPort interface inside. These things seem to do vaguely what I want but when it comes to audio, the specifications are less clear. Any suggestions very welcome.

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• Compress file to bytes for uploading to SQL Server

  - by Chris

  I am trying to zip files to an SQL Server database table. I can't ensure that the user of the tool has write priveledges on the source file folder so I want to load the file into memory, compress it to an array of bytes and insert it into my database. This below does not work. class ZipFileToSql { public event MessageHandler Message; protected virtual void OnMessage(string msg) { if (Message != null) { MessageHandlerEventArgs args = new MessageHandlerEventArgs(); args.Message = msg; Message(this, args); } } private int sourceFileId; private SqlConnection Conn; private string PathToFile; private bool isExecuting; public bool IsExecuting { get { return isExecuting; } } public int SourceFileId { get { return sourceFileId; } } public ZipFileToSql(string pathToFile, SqlConnection conn) { isExecuting = false; PathToFile = pathToFile; Conn = conn; } public void Execute() { isExecuting = true; byte[] data; byte[] cmpData; //create temp zip file OnMessage("Reading file to memory"); FileStream fs = File.OpenRead(PathToFile); data = new byte[fs.Length]; ReadWholeArray(fs, data); OnMessage("Zipping file to memory"); MemoryStream ms = new MemoryStream(); GZipStream zip = new GZipStream(ms, CompressionMode.Compress, true); zip.Write(data, 0, data.Length); cmpData = new byte[ms.Length]; ReadWholeArray(ms, cmpData); OnMessage("Saving file to database"); using (SqlCommand cmd = Conn.CreateCommand()) { cmd.CommandText = @"MergeFileUploads"; cmd.CommandType = CommandType.StoredProcedure; //cmd.Parameters.Add("@File", SqlDbType.VarBinary).Value = data; cmd.Parameters.Add("@File", SqlDbType.VarBinary).Value = cmpData; SqlParameter p = new SqlParameter(); p.ParameterName = "@SourceFileId"; p.Direction = ParameterDirection.Output; p.SqlDbType = SqlDbType.Int; cmd.Parameters.Add(p); cmd.ExecuteNonQuery(); sourceFileId = (int)p.Value; } OnMessage("File Saved"); isExecuting = false; } private void ReadWholeArray(Stream stream, byte[] data) { int offset = 0; int remaining = data.Length; float Step = data.Length / 100; float NextStep = data.Length - Step; while (remaining > 0) { int read = stream.Read(data, offset, remaining); if (read <= 0) throw new EndOfStreamException (String.Format("End of stream reached with {0} bytes left to read", remaining)); remaining -= read; offset += read; if (remaining < NextStep) { NextStep -= Step; } } } }

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• How do I capture my second monitor using avconv?

  - by Codemonkey

  With this command: avconv -f x11grab -s 2560x1440 -i :0.0 I can stream video from my main monitor. I also have a second, 1080p monitor on which I do my gaming. I want to stream from that monitor. This doesn't work: avconv -f x11grab -s 1920x1080 -i :0.1 I assume I have to use -i :0.0 and somehow specify that it should capture 1920x1080 pixels from X position 2560 and Y position 0. My gaming monitor is placed to the right of my main monitor. Unfortunately the man page for avconv is miles long, so I haven't had any luck figuring this out on my own. I have tried Using -vf with crop like this: -vcodec libx264 ... -vf "crop=$IN_WIDTH:$IN_HEIGHT:2560:360" But that only displayed 1080p video from the top left corner of my main display.

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• configuring slime in emacs

  - by CodeKingPlusPlus

  I am in the process of configuring slime for emacs. So far I have read about basic functionality for common lisp such as C-c C-q which invokes the command slime-close-parens-at-point which places the proper number of parens where your mouse is. Another command that seemed cool was invoked by C-c C-c and it would pass the code you are editing in a buffer to the REPL, and "compile" it. Why won't these commands work for me? Anyway, I have downloaded slime via M-x list-packages and do not seem to have this functionality (C-h w and then any of these commands tells me that these commands do note exist). So, I saw a bunch of other slime extensions such as slime-repl', 'slime-fuzzy' and 'hippie-expand-slime'. So I again usedM-x list-packages` and downloaded them. Still I did not have these commands. Here is the content of my emacs file relevant to slime: ;;;Common Lisp and Slime (add-to-list 'load-path "/home/s2s2/.emacs.d/elpa/slime-20130626.1151") (add-to-list 'load-path "/home/s2s2/.emacs.d/elpa/slime-repl-201000404") (add-to-list 'load-path "/home/s2s2/.emacs.d/elpa/hippie-expand-slime-20130226.1656") (add-to-list 'load-path "/home/s2s2/.emacs.d/elpa/slime-fuzzy-20100404") (require 'slime) (setq slime-lisp-implementations `((sbcl ("/usr/bin/sbcl")) (ecl ("/usr/bin/ecl")) (clisp ("/usr/bin/clisp" "-q -I")))) (require 'slime-repl) (require 'slime-fuzzy) (require 'hippie-expand-slime) When I execute M-x slime I get the following message in the inferior-lisp buffer where I can execute common lisp code (however, shouldn't this be the slime-repl since I required it?): STYLE-WARNING: redefining EMACS-INSPECT (#<BUILT-IN-CLASS T>) in DEFMETHOD STYLE-WARNING: Implicitly creating new generic function STREAM-READ-CHAR-WILL-HANG-P. WARNING: These Swank interfaces are unimplemented: (DISASSEMBLE-FRAME SLDB-BREAK-AT-START SLDB-BREAK-ON-RETURN) ;; Swank started at port: 46533. Then a slime-error buffer is created with the contents: Invalid protocol message: Symbol "CREATE-REPL" not found in the SWANK package. Line: 1, Column: 28, File-Position: 28 Stream: #<SB-IMPL::STRING-INPUT-STREAM {10056B9C33}> (:emacs-rex (swank:create-repl nil) "COMMON-LISP-USER" t 5) How should I modify my emacs file to give me the functionality of those commands? In my emacs file am I not loading the necessary files? Do I need to install an additional package? If you need more information let me know! All help is much appreciated!

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• What's the false operator in C# good for?

  - by Jakub Šturc

  There are two weird operators in C#: the true operator the false operator If I understand this right these operators can be used in types which I want to use instead of a boolean expression and where I don't want to provide an implicit conversion to bool. Let's say I have a following class: public class MyType { public readonly int Value; public MyType(int value) { Value = value; } public static bool operator true (MyType mt) { return mt.Value > 0; } public static bool operator false (MyType mt) { return mt.Value < 0; } } So I can write the following code: MyType mTrue = new MyType(100); MyType mFalse = new MyType(-100); MyType mDontKnow = new MyType(0); if (mTrue) { // Do something. } while (mFalse) { // Do something else. } do { // Another code comes here. } while (mDontKnow) However for all the examples above only the true operator is executed. So what's the false operator in C# good for? Note: More examples can be found here, here and here.

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• DVD playback with Windows Media Player 11 works fine, but when copied to HDD and then played back, t

  - by stakx

  I have several DVDs with short documentaries on it. Since the notebook I'm using (a Dell Latitude E6400) has only one DVD drive, and I might play back those short movies very often, I thought of copying them to the HDD and playing them back from there. However, I've run into a problem, namely stuttering audio. Problem description: When I play back these movies directly from DVD (with Windows Media Player 11 under Windows Vista), everything works fine. Smooth video, no significant audio problems (only the occasional click). But as soon as I copy any of these DVDs to the HDD and try to play them back from there (e.g. using the wmpdvd://drive/title/chapter?contentdir=path protocol, I get stuttering audio — audio playback sounds like a machine gun for a third of a second or so, approx. every 8 seconds. I have tried converting the VOB files from the DVD to another format (ie. ripping), but that resulted in a noticeable downgrade of picture quality. Therefore I thought it best to keep the files in their original format, if possible. Still, I suspect that the stuttering audio is due to some (de-)muxing problem, and that changing the file format might help. (After all, video playback is fine; therefore I don't think that the hardware is too slow for playback.) Only thing is, I don't know how to convert the VOB files to another Windows Media Player-compatible format without quality loss. I hope someone can help me, or give me further pointers on things I could try out to get HDD playback to work without the problem described. Some things I've tried so far, without any success: VOB2MPG, in order to convert the .vob file to a .mpg file. But that changes only the A/V container, not the content. No re-encoding takes place at all. Re-encoding with MPlayer/MEncoder. Lots of quality loss there, and I frankly haven't got the time to test all possible settings combinations available. Disabling all plug-ins, equalizers, etc. in Windows Media Player. Disabling all hardware acceleration on the audio playback device. Further info on the VOB files I'm trying to playback: The video format is MPEG ES, PAL 720x576 pixels @ 24/25 frames per second. The sound stream is uncompressed PCM, 16-bit stereo @ 48kHz. (Might it help if I somehow re-encoded the sound stream at a lower resolution, or as an MP3? If so, how would I do this without changing the video stream?) P.S.: I am limited to using Windows Media Player (11). (I previously tried MPlayer btw., but the video playback quality was surprisingly bad.)

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• Artefacts during HDV capture

  - by Jakub Konecki

  When I try to capture HDV video stream from a Canon HV20 camera to a Dell Studio 1558 (Intel i7 720qm) laptop running Win 7 Home Premium x64, the image appears with a very annoying noise - it contains block artefacts. Something is wrong with the Fire Wire controller (Ricoh 1304 OHCI host controller, build-in). Tried changing the driver to legacy one to no avail. This does not happen with DV stream. I'm using a Belkin cable. The capture works OK on another machine.

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• Can I compare a template variable to an integer in Django/App Engine templates?

  - by matt b

  Using Django templates in Google App Engine (on Python), is it possible to compare a template variable to an integer in an {% if %} block? views.py: class MyHandler(webapp.RequestHandler): def get(self): foo_list = db.GqlQuery(...) ... template_values['foos'] = foo_list template_values['foo_count'] = len(foo_list) handler.response.out.write(template.render(...)) My template: {% if foo_count == 1 %} There is one foo. {% endif %} This blows up with 'if' statement improperly formatted. What I was attempting to do in my template was build a simple if/elif/else tree to be grammatically correct to be able to state #foo_count == 0: There are no foos. #foo_count == 1: There is one foo. #else: There are {{ foos|length }} foos. Browsing the Django template documents (this link provided in the GAE documentation appears to be for versions of Django far newer than what is supported on GAE), it appears as if I can only actually use boolean operators (if in fact boolean operators are supported in this older version of Django) with strings or other template variables. Is it not possible to compare variables to integers or non-strings with Django templates? I'm sure there is an easy way to workaround this - built up the message string on the Python side rather than within the template - but this seems like such a simple operation you ought to be able to handle in a template. It sounds like I should be switching to a more advanced templating engine, but as I am new to Django (templates or any part of it), I'd just like some confirmation first.

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• Streaming video file to iPhone

  - by user34157

  I have a http streaming link which gives me .flv streaming feed. I want to convert that and access in my iPhone program. How can i do that? I want to have a desktop software like VLC and input this streaming feed URL and convert to iPhone supported and stream again to iPhone. I tried VLC with H.264 and Mpeg-1 audio, but seems to be it doesn't give the supported format, so as iPhone program doesn't play the video. Could someone please guide me how can i setup a desktop software which can stream iPhone supported file?

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• FFmpeg creates emtpy (black) frames

  - by resamsel

  I have a set of images from a timelapse shot (172 JPG files) that I want to convert into a movie. I tried several parameters with FFmpeg, but all I get is a video with black frames (though it has the expected length). ffmpeg -f image2 -vcodec mjpeg -y -i img_%03d.jpg timelapse2.mpg The command above creates this video: http://sdm-net.org/data/timelapse2.mpg What I'm expecting is something like this (created with Time Lapse Assembler.app): https://vimeo.com/39038362 - This is my fallback option, but I'd really like to create timelapse movies from a script. I'm on OSX Lion (10.7.3) with FFmpeg version (0.10) installed via Homebrew. I also tried to find a proper version of mencoder for OSX, but this doesn't seem to be an easy task. Also, ImageMagick's convert doesn't seem to work nicely, it creates really bad output and it seems there's not much I can do about it... Edit: With libx264 and an mp4 container: ffmpeg -f image2 -y -i img_%03d.jpg -vcodec libx264 timelapse4.mp4 Output: ffmpeg version 0.10 Copyright (c) 2000-2012 the FFmpeg developers built on Mar 26 2012 13:47:02 with clang 3.0 (tags/Apple/clang-211.12) configuration: --prefix=/usr/local/Cellar/ffmpeg/0.10 --enable-shared --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-libfreetype --cc=/usr/bin/clang --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-librtmp --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libass --disable-ffplay libavutil 51. 34.101 / 51. 34.101 libavcodec 53. 60.100 / 53. 60.100 libavformat 53. 31.100 / 53. 31.100 libavdevice 53. 4.100 / 53. 4.100 libavfilter 2. 60.100 / 2. 60.100 libswscale 2. 1.100 / 2. 1.100 libswresample 0. 6.100 / 0. 6.100 libpostproc 52. 0.100 / 52. 0.100 Input #0, image2, from 'img_%03d.jpg': Duration: 00:00:06.88, start: 0.000000, bitrate: N/A Stream #0:0: Video: mjpeg, yuvj420p, 3888x2592 [SAR 72:72 DAR 3:2], 25 fps, 25 tbr, 25 tbn, 25 tbc [buffer @ 0x7f8ec9415f20] w:3888 h:2592 pixfmt:yuvj420p tb:1/1000000 sar:72/72 sws_param: [libx264 @ 0x7f8ec981d800] using SAR=1/1 [libx264 @ 0x7f8ec981d800] frame MB size (243x162) > level limit (36864) [libx264 @ 0x7f8ec981d800] MB rate (984150) > level limit (983040) [libx264 @ 0x7f8ec981d800] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 AVX [libx264 @ 0x7f8ec981d800] profile High, level 5.1 [libx264 @ 0x7f8ec981d800] 264 - core 120 - H.264/MPEG-4 AVC codec - Copyleft 2003-2011 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 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=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00 Output #0, mp4, to 'timelapse4.mp4': Metadata: encoder : Lavf53.31.100 Stream #0:0: Video: h264 (![0][0][0] / 0x0021), yuvj420p, 3888x2592 [SAR 72:72 DAR 3:2], q=-1--1, 25 tbn, 25 tbc Stream mapping: Stream #0:0 -> #0:0 (mjpeg -> libx264) Press [q] to stop, [?] for help frame= 172 fps= 18 q=-1.0 Lsize= 259kB time=00:00:06.80 bitrate= 312.3kbits/s video:256kB audio:0kB global headers:0kB muxing overhead 1.089647% [libx264 @ 0x7f8ec981d800] frame I:1 Avg QP: 9.60 size:212820 [libx264 @ 0x7f8ec981d800] frame P:43 Avg QP:30.50 size: 291 [libx264 @ 0x7f8ec981d800] frame B:128 Avg QP:31.00 size: 285 [libx264 @ 0x7f8ec981d800] consecutive B-frames: 0.6% 0.0% 1.7% 97.7% [libx264 @ 0x7f8ec981d800] mb I I16..4: 22.5% 77.2% 0.3% [libx264 @ 0x7f8ec981d800] mb P I16..4: 0.0% 0.0% 0.0% P16..4: 0.0% 0.0% 0.0% 0.0% 0.0% skip:100.0% [libx264 @ 0x7f8ec981d800] mb B I16..4: 0.0% 0.0% 0.0% B16..8: 0.0% 0.0% 0.0% direct: 0.0% skip:100.0% L0: 1.2% L1:98.8% BI: 0.0% [libx264 @ 0x7f8ec981d800] 8x8 transform intra:77.2% inter:100.0% [libx264 @ 0x7f8ec981d800] coded y,uvDC,uvAC intra: 41.2% 23.4% 0.6% inter: 0.0% 0.0% 0.0% [libx264 @ 0x7f8ec981d800] i16 v,h,dc,p: 40% 25% 35% 1% [libx264 @ 0x7f8ec981d800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 36% 32% 30% 1% 0% 0% 0% 0% 0% [libx264 @ 0x7f8ec981d800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 51% 40% 6% 1% 1% 0% 1% 0% 1% [libx264 @ 0x7f8ec981d800] i8c dc,h,v,p: 60% 21% 19% 0% [libx264 @ 0x7f8ec981d800] Weighted P-Frames: Y:0.0% UV:0.0% [libx264 @ 0x7f8ec981d800] ref P L0: 92.3% 0.0% 0.0% 7.7% [libx264 @ 0x7f8ec981d800] ref B L0: 50.0% 0.0% 50.0% [libx264 @ 0x7f8ec981d800] ref B L1: 99.4% 0.6% [libx264 @ 0x7f8ec981d800] kb/s:304.49 Output timelapse4.mp4 (beacause of spam protection I can only post two links with my reputation): http sdm-net.org/data/timelapse4.mp4

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• Home Media Streaming Server

  - by sharjeel

  I'm looking for a Home Media Server which can stream videos to various devices including iPhone, iPad, Windows Machines, Android etc. I wouldn't want to install any client on any device; a web interface will be preferred. Also, it should be able to read videos of as many formats as possible and should stream by transcoding the resolution and format according to device's specifications. I have a fairly powerful machine on which I'm free to install Windows 7 or Linux. The streaming will be done over a g/n WiFi router or Ethernet locally. What is the suggested solution in my case?

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• implementing cryptographic algorithms, specifically the key expansion part

  - by masseyc

  Hey, recently I picked up a copy of Applied Cryptography by Bruce Schneier and it's been a good read. I now understand how several algorithms outlined in the book work, and I'd like to start implementing a few of them in C. One thing that many of the algorithms have in common is dividing an x-bit key, into several smaller y-bit keys. For example, blowfish's key, X, is 64-bits, but you are required to break it up into two 32-bit halves; Xl and Xr. This is where I'm getting stuck. I'm fairly decent with C, but I'm not the strongest when it comes to bitwise operators and the like. After some help on IRC, I managed to come up with these two macros: #define splitup(a, b, c) {b = a >> 32; c = a & 0xffffffff; } #define combine(a, b, c) {a = (c << 32) | a;} Where a is 64 bits and b and c are 32 bits. However, the compiler warns me about the fact that I'm shifting a 32 bit variable by 32 bits. My questions are these: what's bad about shifting a 32-bit variable 32 bits? I'm guessing it's undefined, but these macros do seem to be working. Also, would you suggest I go about this another way? As I said, I'm fairly familiar with C, but bitwise operators and the like still give me a headache.

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• C standard addressing simplification inconsistency

  - by Chris Lutz

  Section §6.5.3.2 "Address and indirection operators" ¶3 says (relevant section only): The unary & operator returns the address of its operand. ... If the operand is the result of a unary * operator, neither that operator nor the & operator is evaluated and the result is as if both were omitted, except that the constraints on the operators still apply and the result is not an lvalue. Similarly, if the operand is the result of a [] operator, neither the & operator nor the unary * that is implied by the [] is evaluated and the result is as if the & operator were removed and the [] operator were changed to a + operator. ... This means that this: int *i = NULL; printf("%p", (void *) (&*i) ); printf("%p", (void *) (&i[10]) ); Should be perfectly legal, printing the null pointer (probably 0) and the null pointer plus 10 (probably 10). The standard seems very clear that both of those cases are required to be optimized. However, it doesn't seem to require the following to be optimized: struct { int a; short b; } *s = 0; printf("%p", (void *) (&s->b) ); This seems awfully inconsistent. I can see no reason that the above code shouldn't print the null pointer plus sizeof(int) (possibly 4). Simplifying a &-> expression is going to be the same conceptually (IMHO) as &[], a simple address-plus-offset. It's even an offset that's going to be determinable at compile time, rather than potentially runtime with the [] operator. Is there anything in the rationale about why this is so seemingly inconsistent?

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• Why is my Output distorted after encoding with Expression Encoder?

  - by WernerCD

  I'm a "n00b" when it comes to re-encoding files. I'm trying to re-encode an AVI into a silverlight container via Encoding Video using Expression Encoder 4.0. As you can see in the video, the left is the input and it looks/sounds fine. The right is the output and it... doesn't. I'm unsure of where to go from here. I'm not sure why the output is jacked up, since the input looks fine. Input Video properties: AVI 2.49GB 22:34 809x605 Video: TSCC 809x605 15fps [Stream 00] Audio: PCM 22050Hz mono 352kbps [Stream 01] Choice of output doesn't seem to matter, they all end up distorted like the picture shows.

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• Is Windows Media Player able to play DTS audio?

  - by rolgae

  I'm trying to play DTS audio with Windows Media Player 12 on Windows 7. For a MPEG-TS file with video and DTS audio, only video is played. A file containing only a DTS audio stream is rejected. But: WMP is able to play the DTS audio stream of a DVD. So, Is Windows Media Player able to play DTS audio, or not? And if: How do I make him play my DTS files? I did not find any good resources of the supported codecs. Just things like "WMP can play .mpg files, ..." VLC is able to play all of the above files. I do not want to install third party codec packs, thats not the question!

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• Screen Casting using ffmpeg (too fast)

  - by rowman

  I can use ffmpeg to make screen casts: ffmpeg -f x11grab -s 1280x800 -i :0.0 -c:v libx264 -framerate 30 -r 30 -crf 18 out.mkv However the output comes out to be too fast paced. It also happens with GTK RecordMyDesktop if I enable the encode on the fly. So, the questions is how to get a normal video pace. Also in order to capture the sound with ffmpeg what option should be used? FFmpeg Output: ffmpeg -f x11grab -s 1280x800 -r 30 -i :0.0 -c:v libx264 -framerate 30 -r 30 -crf 18 out.mkv ffmpeg version N-35162-g87244c8 Copyright (c) 2000-2012 the FFmpeg developers built on Oct 7 2012 15:56:19 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5) configuration: --enable-gpl --enable-libfaac --enable-libfdk-aac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-librtmp --enable-libtheora --enable-libvorbis --enable-libvpx --enable-x11grab --enable-libx264 --enable-nonfree --enable-version3 libavutil 51. 73.102 / 51. 73.102 libavcodec 54. 64.100 / 54. 64.100 libavformat 54. 29.105 / 54. 29.105 libavdevice 54. 3.100 / 54. 3.100 libavfilter 3. 19.102 / 3. 19.102 libswscale 2. 1.101 / 2. 1.101 libswresample 0. 16.100 / 0. 16.100 libpostproc 52. 1.100 / 52. 1.100 [x11grab @ 0xab896a0] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 1280 height: 800 [x11grab @ 0xab896a0] shared memory extension found [x11grab @ 0xab896a0] Estimating duration from bitrate, this may be inaccurate Input #0, x11grab, from ':0.0': Duration: N/A, start: 1350136942.608988, bitrate: 983040 kb/s Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1280x800, 983040 kb/s, 30 tbr, 1000k tbn, 30 tbc [libx264 @ 0xab87320] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64 SlowCTZ SlowAtom [libx264 @ 0xab87320] profile High 4:4:4 Predictive, level 3.2, 4:4:4 8-bit [libx264 @ 0xab87320] 264 - core 128 r2 198a7ea - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=4 threads=6 lookahead_threads=1 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=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=18.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00 Output #0, matroska, to 'out.mkv': Metadata: encoder : Lavf54.29.105 Stream #0:0: Video: h264, yuv444p, 1280x800, q=-1--1, 1k tbn, 30 tbc Stream mapping: Stream #0:0 -> #0:0 (rawvideo -> libx264) Press [q] to stop, [?] for help frame= 10 fps=0.0 q=0.0 size= 1kB time=00:00:00.00 bitrate= 0.0kbits/sframe= 19 fps= 17 q=0.0 size= 1kB time=00:00:00.00 bitrate= 0.0kbits/sframe= 28 fps= 17 q=0.0 size= 1kB time=00:00:00.00 bitrate= 0.0kbits/sframe= 37 fps= 17 q=0.0 size= 1kB time=00:00:00.00 bitrate= 0.0kbits/sframe= 45 fps= 16 q=0.0 size= 1kB time=00:00:00.00 bitrate= 0.0kbits/sframe= 47 fps= 14 q=0.0 size= 1kB time=00:00:00.00 bitrate= 0.0kbits/sframe= 52 fps= 13 q=24.0 size= 257kB time=00:00:00.00 bitrate=2101632.0kbiframe= 55 fps= 12 q=24.0 size= 257kB time=00:00:00.10 bitrate=20808.2kbitsframe= 59 fps= 11 q=24.0 size= 289kB time=00:00:00.23 bitrate=10145.0kbitsframe= 64 fps= 11 q=24.0 size= 289kB time=00:00:00.40 bitrate=5894.7kbits/frame= 70 fps= 11 q=24.0 size= 289kB time=00:00:00.60 bitrate=3933.1kbits/frame= 72 fps= 10 q=24.0 size= 289kB time=00:00:00.66 bitrate=3549.2kbits/frame= 77 fps=9.8 q=24.0 size= 289kB time=00:00:00.83 bitrate=2837.7kbits/frame= 80 fps=9.6 q=24.0 size= 289kB time=00:00:00.93 bitrate=2533.5kbits/frame= 85 fps=9.3 q=24.0 size= 289kB time=00:00:01.10 bitrate=2146.9kbits/frame= 89 fps=9.3 q=24.0 size= 289kB time=00:00:01.23 bitrate=1917.1kbits/frame= 92 fps=9.1 q=24.0 size= 289kB time=00:00:01.33 bitrate=1773.3kbits/frame= 96 fps=9.0 q=24.0 size= 289kB time=00:00:01.46 bitrate=1612.4kbits/frame= 99 fps=8.8 q=24.0 size= 321kB time=00:00:01.56 bitrate=1676.8kbits/frame= 104 fps=8.7 q=24.0 size= 321kB time=00:00:01.73 bitrate=1515.2kbits/frame= 109 fps=5.3 q=24.0 Lsize= 1093kB time=00:00:03.56 bitrate=2511.5kbits/s video:1092kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.120198% [libx264 @ 0xab87320] frame I:3 Avg QP:18.93 size:142610 [libx264 @ 0xab87320] frame P:43 Avg QP:20.79 size: 15751 [libx264 @ 0xab87320] frame B:63 Avg QP:23.75 size: 195 [libx264 @ 0xab87320] consecutive B-frames: 21.1% 1.8% 11.0% 66.1% [libx264 @ 0xab87320] mb I I16..4: 50.0% 21.1% 28.9% [libx264 @ 0xab87320] mb P I16..4: 6.1% 0.9% 3.2% P16..4: 5.5% 1.2% 0.6% 0.0% 0.0% skip:82.5% [libx264 @ 0xab87320] mb B I16..4: 0.4% 0.1% 0.0% B16..8: 2.9% 0.1% 0.0% direct: 0.0% skip:96.5% L0:40.7% L1:57.0% BI: 2.3% [libx264 @ 0xab87320] 8x8 transform intra:14.5% inter:46.1% [libx264 @ 0xab87320] coded y,u,v intra: 33.5% 24.1% 25.4% inter: 0.9% 0.4% 0.4% [libx264 @ 0xab87320] i16 v,h,dc,p: 70% 26% 1% 3% [libx264 @ 0xab87320] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 11% 21% 30% 5% 7% 5% 7% 4% 10% [libx264 @ 0xab87320] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 32% 35% 12% 2% 4% 3% 4% 3% 5% [libx264 @ 0xab87320] Weighted P-Frames: Y:0.0% UV:0.0% [libx264 @ 0xab87320] ref P L0: 57.0% 5.6% 26.8% 10.6% [libx264 @ 0xab87320] ref B L0: 69.4% 22.6% 8.0% [libx264 @ 0xab87320] ref B L1: 93.7% 6.3% [libx264 @ 0xab87320] kb/s:2460.40

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• Macro and array crossing

  - by Thomas

  I am having a problem with a lisp macro. I would like to create a macro which generate a switch case according to an array. Here is the code to generate the switch-case: (defun split-elem(val) `(,(car val) ',(cdr val))) (defmacro generate-switch-case (var opts) `(case ,var ,(mapcar #'split-elem opts))) I can use it with a code like this: (generate-switch-case onevar ((a . A) (b . B))) But when I try to do something like this: (defparameter *operators* '((+ . OPERATOR-PLUS) (- . OPERATOR-MINUS) (/ . OPERATOR-DIVIDE) (= . OPERATOR-EQUAL) (* . OPERATOR-MULT))) (defmacro tokenize (data ops) (let ((sym (string->list data))) (mapcan (lambda (x) (generate-switch-case x ops)) sym))) (tokenize data *operators*) I got this error: *** - MAPCAR: A proper list must not end with OPS. But I don't understand why. When I print the type of ops I get SYMBOL I was expecting CONS, is it related? Also, for my function tokenize how many times the lambda is evaluated (or the macro expanded)?

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• Evaluate an expression tree

  - by Phronima

  Hi, This project that I'm working on requires that an expression tree be constructed from a string of single digit operands and operators both represented as type char. I did the implmentation and the program up to that point works fine. I'm able to print out the inorder, preorder and postorder traversals in the correct way. The last part calls for evaulating the expression tree. The parameters are an expression tree "t" and its root "root". The expression tree is ((3+2)+(6+2)) which is equal to 13. Instead I get 11 as the answer. Clearly I'm missing something here and I've done everything short of bashing my head against the desk. I would greatly appreciate it if someone can point me in the right direction. (Note that at this point I'm only testing addition and will add in the other operators when I get this method working.) public int evalExpression( LinkedBinaryTree t, BTNode root ) { if( t.isInternal( root ) ) { int x = 0, y = 0, value = 0; char operator = root.element(); if( root.getLeft() != null ) x = evalExpression(t, t.left( root ) ); if( root.getRight() != null ) y = evalExpression(t, t.right( root ) ); if( operator == '+' ) { value = value + Character.getNumericValue(x) + Character.getNumericValue(y); } return value; } else { return root.element(); } }

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• Bsplayer - load audio tracks from external files

  - by torran

  I have a movie file: Video ID : 1 Format : AVC Format/Info : Advanced Video Codec Format profile : [email protected] Format settings, CABAC : Yes Format settings, ReFrames : 5 frames Muxing mode : Container [email protected] Codec ID : V_MPEG4/ISO/AVC Duration : 54mn 13s Bit rate : 3 380 Kbps Nominal bit rate : 3 459 Kbps Width : 1 280 pixels Height : 720 pixels Display aspect ratio : 16:9 Frame rate : 23.976 fps Resolution : 8 bits Colorimetry : 4:2:0 Scan type : Progressive Bits/(Pixel*Frame) : 0.153 Stream size : 1.28 GiB (88%) Writing library : x264 core 88 r1471 1144615 Audio ID : 2 Format : AC-3 Format/Info : Audio Coding 3 Codec ID : A_AC3 Duration : 54mn 16s Bit rate mode : Constant Bit rate : 384 Kbps Channel(s) : 6 channels Channel positions : Front: L C R, Side: L R, LFE Sampling rate : 48.0 KHz Stream size : 149 MiB (10%) and additional audio files in same folder: .mp3 and .ac3. How can I load them with bsplayer? Right click-audio-audio streams is empty. If i open the movie with media players classic I can switch audio files.

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• What music streaming app fits my needs on Ubuntu?

  - by Jim

  I'm looking for an application to stream Internet radio on Ubuntu. I like listening to Radio Paradise while I work. Right now, I'm using Amarok. "Movie Player" sometimes refuses to open the stream, and VLC doesn't keep its window title updated with the currently playing track. Amarok has nice translucent notifications when tracks change, but track changes in streams don't trigger the notifications. Mostly, I want something that reliably opens streams and makes it easy to see the name of the track that's playing. If it has a built-in directory of streaming radio stations, that would be a big benefit.

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