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• FFMPEG video streaming error

  2 octobre 2013, par Vigo

  I have downloaded FFMPEG static builds for carrying out audio/video streaming on a LAN. A webcam captures the video and this has to be streamed. I use the following command to know the name of the video device connected.

  ffmpeg -list_devices true -f dshow -i dummy  

  The webcam connected is "USB Video Device".
  Next i use the following command to transmit the video.

  ffmpeg -f dshow -i video="USB Video Device" -vcodec libx264 -tune zerolatency -b 900k -f rtp rtp://10.1.0.102:1234  

  But it throws me the error "Could not run filter. video=USB Video Device : Input/output error" as shown below.

  

  Please let me know what is the issue here.

• webm local udp streaming using FFMPEG

  1er octobre 2013, par siniv

  I was just started to use ffmpeg recently and stumbled on this streaming problem.
  Scenario : i want to live stream a webcam in local network. Both server and client will be using windows platform.

  Current feasible solution : using ffmpeg simple command line

  to test it quickly i tried to locally stream it (the input doesn't really matter btw in this question).

   On server -> ffmpeg -f dshow -i video="cam1":audio="mic1" -r 30 -g 0 -vcodec h264 -acodec libmp3lame -tune zerolatency -preset ultrafast -f mpegts udp://localhost:6789
  
   On client(the same computer) -> ffplay udp://localhost:6789

  The above works just fine, except for the latency, which i'm getting at about 1-2 second delay.

  Now i want to try to change the encoder to use libvpx (vp8) for video and vorbis for audio (i changed the input to a pre-recorded h264 video, but it really doesn't matter)

   On server 
  
      >ffmpeg -i "suits.mp4" -r 30 -g 0 -vcodec libvpx -acodec vorbis -strict -2 -f webm -f mpegts udp://localhost:6789
  
       On client(the same computer) -> ffplay udp://localhost:6789
  
  However this doesn't work... And below are console outputs:
  
      > onserver ->
  
      > ffmpeg version N-56165-gae12d65 Copyright (c) 2000-2013 the FFmpeg
  
      > developers   built on Sep 10 2013 19:42:46 with gcc 4.7.3 (GCC)  
  
      > configuration: --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-libx264 --enable-libxavs --enable-libxvid --enable-zlib   libavutil      52. 43.100 / 52. 43.100   libavcodec     55. 31.101 / 55. 31.101   libavformat    55. 16.102 / 55. 16.102   libavdevice    55.  3.100 / 55.  3.100   libavfilter     3. 84.100 /  3. 84.100   libswscale      2.  5.100 / 
  
      > 2.  5.100   libswresample   0. 17.103 /  0. 17.103   libpostproc    52.  3.100 / 52.  3.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Suits.mp4':   Metadata:
  
      >     major_brand     : isom
  
      >     minor_version   : 1
  
      >     compatible_brands: isom
  
      >     creation_time   : 2011-09-08 11:43:25   Duration: 00:42:14.87, start: 0.000000, bitrate: 882 kb/s
  
      >     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 720x402 [SAR 1:1 DAR 120:67], 750 kb/s, 23.98 fps,
  
      > 23.98 tbr, 24k tbn, 47.95 tbc (default)
  
      >     Metadata:
  
      >       creation_time   : 2011-09-08 11:43:25
  
      >     Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 126 kb/s (default)
  
      >     Metadata:
  
      >       creation_time   : 2011-09-08 11:43:25 [libvpx @ 05392a80] v1.2.0 Output #0, mpegts, to 'udp://localhost:6789':   Metadata:
  
      >     major_brand     : isom
  
      >     minor_version   : 1
  
      >     compatible_brands: isom
  
      >     encoder         : Lavf55.16.102
  
      >     Stream #0:0(und): Video: vp8 (libvpx), yuv420p, 720x402 [SAR 1:1 DAR 120:67], q=-1--1, 200 kb/s, 90k tbn, 30 tbc (default)
  
      >     Metadata:
  
      >       creation_time   : 2011-09-08 11:43:25
  
      >     Stream #0:1(und): Audio: vorbis, 48000 Hz, stereo, fltp (default)
  
      >     Metadata:
  
      >       creation_time   : 2011-09-08 11:43:25 Stream mapping:   Stream #0:0 -> #0:0 (h264 -> libvpx)   Stream #0:1 -> #0:1 (aac -> vorbis) Press [q] to stop, [?] for help frame=42535 fps= 51 q=0.0 Lsize= 
  
      > 143539kB time=00:23:38.28 bitrate= 829.1kbits/s dup=8541 drop=0    
  
      > video:99155kB audio:28125kB subtitle:0 global headers:3kB muxing
  
      > overhead 12.772155% Received signal 2: terminating.
  
  
  
  > on client    
  
  > ffplay version N-56165-gae12d65 Copyright (c) 2003-2013 the FFmpeg
  
  > developers   built on Sep 10 2013 19:42:46 with gcc 4.7.3 (GCC)  
  
  > configuration: --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-libx264 --enable-libxavs --enable-libxvid --enable-zlib   libavutil      52. 43.100 / 52. 43.100   libavcodec     55. 31.101 / 55. 31.101   libavformat    55. 16.102 / 55. 16.102   libavdevice    55.  3.100 / 55.  3.100   libavfilter     3. 84.100 /  3. 84.100   libswscale      2.  5.100 / 
  
  > 2.  5.100   libswresample   0. 17.103 /  0. 17.103   libpostproc    52.  3.100 / 52.  3.100
  
  >     nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   [mpegts @ 02eb8620] probed stream 0 failed
  
  >     nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   [mp3 @ 02ed75a0] Header missing
  
  >     Last message repeated 1 times [mp3 @ 02ed75a0] Header missing
  
  >     La    Last message repeated 13 times
  
  >     nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   [mp3 @ 02ed75a0] Header missing  Last message repeated 13 times
  
  >     nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   [mp3 @ 02ed75a0] Header missing    Last message repeated 9 times
  
  >     nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   [mp3 @ 02ed75a0] Header missing [mpegts @ 02eb8620] decoding for
  
  > stream 1 failed [mpegts @ 02eb8620] Could not find codec parameters
  
  > for stream 0 (Unknown: none ([6][0][0][0] / 0x0006)): unknown codec
  
  > Consider increasing the value for the 'analyzeduration' and
  
  > 'probesize' options [mpegts @ 02eb8620] Could not find codec
  
  > parameters for stream 1 (Audio: mp3 ([6][0][0][0] / 0x0006), 0
  
  > channels, s16p): unspecified frame size Consider increasing the value
  
  > for the 'analyzeduration' and 'probesize' options
  
  > udp://localhost:6789: could not find codec parameters

  So does the point to point streaming for ffmpeg just doesn't work for vp8 or am i missing something ? Btw, the end goal is to create a similar video chat based framework and i'll appreciate any suggestion. I'm reading up on webRTC now.

• Interfacing to an Xbox Optical Drive

  1er octobre 2013, par Multimedia Mike — xbox

  The next generation Xbox is going to hit the streets soon. But for some reason, I’m still interested in the previous generation’s unit (i.e., the original Xbox). Specifically, I’ve always wondered if it’s possible to use the original Xbox’s optical drive in order to read Xbox discs from Linux. I was never curious enough to actually buy an Xbox just to find out but I eventually came across a cast-off console on a recycle pile.

  I have long known that the Xbox has what appears to be a more or less standard optical drive with a 40-pin IDE connector. The only difference is the power adapter which I surmise is probably the easiest way to turn a bit of standardized hardware into a bit of proprietary hardware. The IDE and power connectors look like this :

  
  
  

  Thus, I wanted to try opening an Xbox and plugging the optical drive into a regular PC, albeit one that supports IDE cables, and allow the Xbox to supply power to the drive. Do you still have hardware laying around that has 40-pin IDE connectors ? I guess my Mac Mini PPC fits the bill, but I’ll be darned if I’m going to pry that thing open again. I have another IDE-capable machine buried in my closet, last called into service when I needed a computer with a native RS-232 port 3 years ago. The ordeal surrounding making this old computer useful right now can be another post entirely.

  Here’s what the monstrosity looks like thanks to characteristically short IDE cable lengths :

  
  

  

  Click for larger image

  
  

  Process :

  1. Turn on Xbox first
  2. Turn on PC

  Doing these things in the opposite order won’t work since the kernel really wants to see the drive when booting up. Inspecting the 'dmesg' log afterward reveals interesting items :
  

  <br />
hdd: PHILIPS XBOX DVD DRIVE, ATAPI CD/DVD-ROM drive<br />
hdd: host max PIO5 wanted PIO255(auto-tune) selected PIO4<br />
hdd: UDMA/33 mode selected<br />
[...]<br />
hdd: ATAPI DVD-ROM drive, 128kB Cache<br />

  Why is that interesting ? When is the last time to saw disk devices prefixed by ‘hd’ rather than ‘sd’ ? Blast from the past. Oh, and the optical drive’s vendor string clearly indicates that this is an Xbox drive saying ‘hi !’.

  Time To Read
  When I first studied an Xbox disc in a normal optical drive, I noticed that I was able to read 6992 2048-byte sectors — about 14 MB of data — as reported by the disc table of contents (TOC). This is just enough data to play a standard DVD video animation that kindly instructs the viewer to please use a proper Xbox. At this point, I estimated that there must be something special about Xbox optical drive firmware that knows how to read alternate information on these discs and access further sectors.

  I ran my TOC query tool with an Xbox Magazine demo disc in the optical drive and it reported substantially more than 6992 sectors, enough to account for more than 2 GB of data. That’s promising. I then tried running 'dd' against the device and it was able to read… about 14 MB, an exact quantity of bytes that, when divided by 2048 bytes/sector, yields 6992 sectors.

  Future (Past ?) Work
  Assuming Google is your primary window into the broader internet, the world is beginning to lose its memory of things pertaining to the original Xbox (Microsoft’s naming scheme certainly doesn’t help searches). What I’m saying is that it can be difficult to find information about this stuff now. However, I was able to learn that a host needs to perform a sort of cryptographic handshake with the drive at the SCSI level before it is allowed to access the forbidden areas of the disc. I think. I’m still investigating this and will hopefully post more soon.