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• Methods For Retaining State

  26 décembre 2011, par Multimedia Mike — General, evernote, organization

  I jump around between projects. A lot. Over the years, I have employed various methods for retaining state or context as I switch to a different project. Here’s a quick survey and a general classification of their effectiveness.

  Good

  • Evernote : This is a cloud-based note-taking service that has a web client, Mac and Windows clients, and clients for just about ever mobile platform out there. I have an account and access it via the web interface as as the Windows, iOS, and Android clients. I really like it.

  
  
  

  Okay

  • Series of text files : I have been doing this for a very long time. I have many little note-filled directories here and there that are consistently migrated to new machines but generally forgotten about. This isn’t a terrible method but can be unwieldy when you work on lots of different machines. I’m still tracking down all these directories and importing them into Evernote.

  Bad

  • Layout of desktop windows : I have a habit of working on one project in a set of windows on one desktop space and another project in a second set of windows in another space, etc. Oh, this makes me shudder just thinking about it, mostly because of living in constant fear of a power failure or some other inadvertent reset (darn you, default config’d Windows Update) that wipes the state clean (sure, all of the work might have been saved, but I was relying on those windows to be set up in just the right manner to remind me of all the things I was working on). These days, I force myself to reboot at least once a week so I can’t get too deep into this habit. When it’s time to change projects, I write up exactly what I was doing and where I left off and stick it in Evernote.
  • Open browser windows : I guess it’s common to have many, many tabs open in one’s web browser in this day and age. Like many, I use open tabs as a stack of items to read. The state problem comes when a few of the open tabs represent TODO items. Then I start living in fear that the browser might crash or be restarted in an unexpected way and I struggle to recall what 3-5 important TODO items were that I had opened in separate tabs (on top of a stack of less important items). Again, I try to shut down the browser frequently in order to break this tendency. TODO items are better filed in Evernote.
  • Unsaved data in a text editor : Okay, this is just sloppy on my part, shoving temporary data into a text editor window thinking it’s supremely ephemeral. The problem comes when it’s linked to one of the many tasks on my desktop that might be bumped down a few priority levels ; when finally returning to the context-free data, I’m at a loss to explain what it’s for. Evernote gets it, once more, with a more thorough description of what was going on.
  • Email inbox : I make an effort to ensure that my email inbox has the fewest number of messages possible. Once things are dealt with, they get filed away elsewhere. This implies that things in my inbox require action. Some things have a habit of hanging around, though. Longer items now get described in better detail and filed away in Evernote.
  • Classic paper : Thanks to Derek in the comments for reminding me of this one. Paper is a reliable standby but it can get unwieldy when Post-It Notes litter your work area. Further, it can be problematic when you have multiple physical work areas.
  • Shell history : Another method I rely on entirely too often. This is when I count on a recipe of command line incantations living on in the history buffer of my Unix shell (generally Bash). What sequence of git commands allowed me to do XYZ ? Let’s check the shell history– I sure hope it’s still in there.

  Conclusion
  I guess what I’m trying to say here is that I really like Evernote. If you have similar troubles with retaining state, try it out. I hear there are many other services similar to it with slightly varying feature sets (people rave about Microsoft OneNote). So there are plenty of options and something out there is surely a fit.

  Evernote has a free tier and a premium tier. For my meager note-taking needs, I don’t come anywhere close to the free tier’s limit but I decided to pay for a premium subscription simply because I feel like I derive so much value from the service.

  One downside, however, is that I seem to be doing a lot less blogging since I got on Evernote earlier this year (though it is where I author most of these posts nowadays ; I especially like that I have a notebook labeled “Posted” whose incrementing count reminds me that I am getting some stuff out there). I originally started this blog as a sort of technical journal in order to organize notes and projects in a central location. It’s strange to think that if Evernote existed in 2005, I might never have had a reason to start this blog.

• FFMpeg hello world failed

  13 mai 2014, par xorange

  I’m new to the ffmpeg development.

  I’ve got my ffmpeg via ffmpeg.mplayerhq.hu/download.html using

     `git clone git://source.ffmpeg.org/ffmpeg.git ffmpeg`

  My OS is Win7. I’m using Cygwin to help me work under a Unix-like environment.

  I’m using tutorial code from http://dranger.com/ffmpeg/ffmpeg.html. My current code is Tutorial01.

  So I’ve got my gcc, ffmpeg and code together. Working directory is /ffmpegDemo,

  code : /ffmpegDemo/tutorial01.c

  ffmpeg : /ffmpegDemo/ffmpeg

  And I use command gcc-I ffmpeg -o t01 tutorial01.c to compile my code.
  (cygwin doesn’t support "copy", here’re just some major message :)

  libavutil/avconfig.h : No such file or directory

  ...

  error : ’CODEC_TYPE_VIDEO’ undeclared

  ...

  and others are just warnings.

  Indeed, there’s no avconfig.h under ffmpeg/libavutil. I’ve looked for ’CODEC_TYPE_VIDEO’, here’s this reference : http://cekirdek.pardus.org.tr/ ismail/ffmpeg-docs/avcodec_8h.html says that ’CODEC_TYPE_VIDEO’ is defined in libavcodec/avcodec.h. I’ve checked avcodec.h and didn’t find any.

  I was very confused about this error and confused about all the "configure" and "make" things that I saw while searching for answer. Am I doing it wrong ? Did I miss some steps ? Hope that I could find an answer here.

  Thanks.

• Crossdevice encoding static file to stream in browser using FFMPEG (segmented h264 ?)

  20 mars 2014, par Vprnl

  I'm building a mediacenter application in NodeJS which is going pretty ok.
  (you can check it out on Github : https://github.com/jansmolders86/mediacenterjs )

  I'm using FFMPEG to transcode local (static) movies to a stream which I then send to the browser.

  At first I used h264 with Flash which worked in browsers, but I really need it to work on Android an iOS (so no Flash) and preferably working on a Raspberry Pi.

  But getting it to play on all devices is driving me absolutely insane !

  I have all these bits of the puzzle I've gathered from countless hours reading articles, tutorials and stack overflow posts, which led me to the conclusion that I need to produce the following :

  • Use video codec H264 to transcode to MP4
  • Move the moovatom '-movflags' to make a MP4 streamable
  • Segment the stream so Apple can play the stream as well.

  But getting nowhere with this. Every time I produce a series of FFMPEG settings that either don't work, or work on some devices rather than all.

  Some of my failed attempt where :

  My flash attempt -> Main problem (not running in IOS) :

      '-y','-ss 0','-b 800k','-vcodec libx264','-acodec mp3'\ 
  
      '-ab 128','-ar 44100','-bufsize 62000', '-maxrate 620k'\
  
      metaDuration,tDuration,'-f flv

  my HLS attempt -> Main problem (not running in browser) :

          '-r 15','-b:v 128k','-c:v libx264','-x264opts level=41'\
  
          '-threads 4','-s 640x480','-map 0:v','-map 0:a:0','-c:a mp3'\
  
          '-b:a 160000','-ac 2','-f hls','-hls_time 10','-hls_list_size 6'\
  
          '-hls_wrap 18','-start_number 1'

  My MP4 attempt -> Main problem (duration is shortened and the later part of the video is speeding by)

         '-y','-ss 0','-b 800k','-vcodec libx264','-acodec mp3'\
  
         '-ab 128','-ar 44100','-bufsize 62000', '-maxrate 620k'\
  
         metaDuration,tDuration,'-f mp4','-movflags','frag_keyframe+empty_moov'

  Second MP4 attempt : -> Main problem (duration is shortened and the later part of the video is speeding by)

      '-y','-vcodec libx264','-pix_fmt yuv420p','-b 1200k','-flags +loop+mv4'\
  
      '-cmp 256','-partitions +parti4x4+parti8x8+partp4x4+partp8x8+partb8x8'\
  
      '-me_method hex','-subq 7','-trellis 1','-refs 5','-bf 3','-coder 1'\
  
      '-me_range 16','-g 150','-keyint_min 25','-sc_threshold 40'\
  
      '-i_qfactor 0.71','-acodec mp3','-qmin 10','-qdiff 4','-qmax 51'\
  
      '-ab 128k','-ar 44100','-threads 2','-f mp4','-movflags','frag_keyframe+empty_moov'])

  Here is an example of the FFMPEG log running with these settings :

          file conversion error ffmpeg version N-52458-gaa96439 Copyright (c) 2000-2013 the FFmpeg developers
  
            built on Apr 24 2013 22:19:32 with gcc 4.8.0 (GCC)
  
            configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --e
  
          nable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable
  
          -libgsm --enable-libilbc --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --ena
  
          ble-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwola
  
          me --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enabl
  
          e-libxvid --enable-zlib
  
            libavutil      52. 27.101 / 52. 27.101
  
            libavcodec     55.  6.100 / 55.  6.100
  
            libavformat    55.  3.100 / 55.  3.100
  
            libavdevice    55.  0.100 / 55.  0.100
  
            libavfilter     3. 60.101 /  3. 60.101
  
            libswscale      2.  2.100 /  2.  2.100
  
            libswresample   0. 17.102 /  0. 17.102
  
            libpostproc    52.  3.100 / 52.  3.100
  
          [avi @ 02427900] non-interleaved AVI
  
          Guessed Channel Layout for  Input Stream #0.1 : mono
  
          Input #0, avi, from 'C:/temp/the avengers.avi':
  
            Duration: 00:00:34.00, start: 0.000000, bitrate: 1433 kb/s
  
              Stream #0:0: Video: cinepak (cvid / 0x64697663), rgb24, 320x240, 15 tbr, 15 tbn, 15 tbc
  
              Stream #0:1: Audio: pcm_u8 ([1][0][0][0] / 0x0001), 22050 Hz, mono, u8, 176 kb/s
  
          Please use -b:a or -b:v, -b is ambiguous
  
          [libx264 @ 02527c60] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
          [libx264 @ 02527c60] profile High, level 2.0
  
          [libx264 @ 02527c60] 264 - core 130 r2274 c832fe9 - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x26
  
          4.html - options: cabac=1 ref=5 deblock=1:0:0 analyse=0x3:0x133 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=2 lookahead_threads=1 sliced_th
  
          reads=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 we
  
          ightb=1 open_gop=0 weightp=2 keyint=150 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=1 bitrate=120
  
          0 ratetol=1.0 qcomp=0.60 qpmin=10 qpmax=51 qpstep=4 ip_ratio=1.41 aq=1:1.00
  
          Output #0, mp4, to 'pipe:1':
  
            Metadata:
  
              encoder         : Lavf55.3.100
  
              Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 320x240, q=10-51, 1200 kb/s, 15360 tbn, 15 tbc
  
              Stream #0:1: Audio: mp3 (i[0][0][0] / 0x0069), 44100 Hz, mono, s16p, 128 kb/s
  
          Stream mapping:
  
            Stream #0:0 -> #0:0 (cinepak -> libx264)
  
            Stream #0:1 -> #0:1 (pcm_u8 -> libmp3lame)
  
          Press [q] to stop, [?] for help
  
          frame=  106 fps=0.0 q=10.0 size=       1kB time=00:00:06.94 bitrate=   1.4kbits/s
  
          frame=  150 fps=149 q=14.0 size=       1kB time=00:00:09.87 bitrate=   1.0kbits/s
  
          frame=  191 fps=126 q=16.0 size=       1kB time=00:00:12.61 bitrate=   0.8kbits/s
  
          frame=  244 fps=121 q=16.0 size=    2262kB time=00:00:16.14 bitrate=1147.6kbits/s
  
          frame=  303 fps=120 q=14.0 size=    2262kB time=00:00:20.08 bitrate= 922.2kbits/s
  
          frame=  354 fps=117 q=15.0 size=    3035kB time=00:00:23.48 bitrate=1058.6kbits/s
  
          frame=  402 fps=113 q=15.0 size=    3035kB time=00:00:26.67 bitrate= 932.1kbits/s
  
          frame=  459 fps=113 q=16.0 size=    4041kB time=00:00:30.43 bitrate=1087.7kbits/s
  
          frame=  510 fps=103 q=2686559.0 Lsize=    5755kB time=00:00:33.93 bitrate=1389.3kbits/s
  
  
  
          video:5211kB audio:531kB subtitle:0 global headers:0kB muxing overhead 0.235111%
  
          [libx264 @ 02527c60] frame I:6     Avg QP:10.55  size: 25921
  
          [libx264 @ 02527c60] frame P:245   Avg QP:12.15  size: 14543
  
          [libx264 @ 02527c60] frame B:259   Avg QP:15.55  size:  6242
  
          [libx264 @ 02527c60] consecutive B-frames:  6.1% 73.7% 14.7%  5.5%
  
          [libx264 @ 02527c60] mb I  I16..4: 19.9%  6.2% 73.9%
  
          [libx264 @ 02527c60] mb P  I16..4:  6.0%  0.2% 12.0%  P16..4: 35.4%  9.6% 16.3%  7.0%  5.6%    skip: 7.8%
  
          [libx264 @ 02527c60] mb B  I16..4:  0.7%  0.0%  4.3%  B16..8: 27.6% 17.2% 17.0%  direct:17.3%  skip:15.9%  L0:39.4% L1:43.2%
  
          BI:17.4%
  
          [libx264 @ 02527c60] final ratefactor: 11.41
  
          [libx264 @ 02527c60] 8x8 transform intra:1.6% inter:4.0%
  
          [libx264 @ 02527c60] coded y,uvDC,uvAC intra: 93.0% 97.0% 94.9% inter: 58.4% 58.7% 50.6%
  
          [libx264 @ 02527c60] i16 v,h,dc,p: 15% 26% 54%  5%
  
          [libx264 @ 02527c60] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 17% 39%  4%  4%  3%  1%  6%  9%
  
          [libx264 @ 02527c60] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 28% 34% 21%  4%  2%  2%  2%  2%  5%
  
          [libx264 @ 02527c60] i8c dc,h,v,p: 51% 24% 19%  6%
  
          [libx264 @ 02527c60] Weighted P-Frames: Y:4.1% UV:1.2%
  
          [libx264 @ 02527c60] ref P L0: 68.2%  9.8% 11.0%  5.6%  4.6%  0.8%  0.0%
  
          [libx264 @ 02527c60] ref B L0: 87.7%  8.0%  3.9%  0.4%
  
          [libx264 @ 02527c60] ref B L1: 97.8%  2.2%
  
          [libx264 @ 02527c60] kb/s:1255.36

  Lastly this is my node code fireing up FFMPEG. (I use the module Fluent-ffmpeg : https://github.com/schaermu/node-fluent-ffmpeg )

      var proc = new ffmpeg({ source: movie, nolog: true, timeout:15000})                         
  
          .addOptions(['-r 15','-b:v 128k','-c:v libx264','-x264opts level=41','-threads 4','-s 640x480','-map 0:v','-map 0:a:0','-c:a mp3','-b:a 160000','-ac 2','-f hls','-hls_time 10','-hls_list_size 6','-hls_wrap 18','-start_number 1 stream.m3u8'])
  
          .writeToStream(res, function(retcode, error){
  
              if (!error){
  
                  console.log('file has been converted succesfully',retcode .green);
  
              }else{
  
                  console.log('file conversion error',error .red);
  
              }
  
          });

  So to conclude this very long and code heavy question :

  I hope this does not come off as a lazy request, but could someone show/explain to me which FFMPEG settings could/should work on all platforms (modern browsers, Android and iOS) producing a stream of a static file which I can send to a HTML5 player.

  [EDIT] what I need if a generic option isn't available

  And if this is not possible as some posts might suggest, I would love to see a set of FFMPEG settings that get's the job done properly as far as mp4 streaming is concerned. (e.g encoding a streamable mp4).

  The streaming mp4 needs the following

  • A shifted moovAtom
  • It needs to be h264

  Thanks very much for your help !