Archive for ‘MP4’ Category
Posted on 10:26, November 3rd, 2011 by Many Ayromlou
I’ve already covered how to do this with vlc a while back in parts 1 followed by part 2. I just found out that something very similar in results can be done with ffmpeg. ffmpeg has recently added support for directshow filters which now allows one to capture the screen and stream and/or save it. Here is how you can do this:
1.) Grab a copy of the Screen Capture DirectShow source filter from Unreal Streaming Technologies. It’s about half way down that page. They have both the UScreenCapture X86 Edition and the X64 Edition (depending on your OS installation). I used the 64 bit filter on a Windows 7 64 bit installation.
2.) Install the filter and make sure you make the following changes to your windows registry using regedit. The default frame rate for UScreenCapture filter is 10 f/s and we need to boost this to 30 frames/sec. You need to find the key HKLM\SOFTWARE\UNREAL\Live\UScreenCapture and insert a DWORD value of 30 for FrameRate (You have to create FrameRate, it does not exist by default). Once you’ve done the registry tweak, reboot.
3.) Install the latest greatest version of ffmpeg for your windows version from Zeranoe. I grabbed the 64 bit Static build since I didn’t want to deal with libraries and such. Extract it and stick it somewhere on your hard drive. Remember the path to this folder since we will need it later.
4.) Open a command line window and cd to the directory where you extracted ffmpeg into, find the bin directory and cd into it. This is were the ffmpeg executable resides. In my case (I extracted the ffmpeg files into “Program Files” directory) it is C:\Program Files\ffmpeg-git-059707e-win64-static\bin.
5.) If you’ve made it this far, hand in there, we’re almost home. Now you need to issue the command that gets the screen streaming going. But first we need to find out the name of the Screen filter device. So issue the following command:
In the output look for a device called “UScreenCapture“. Hopefully if everything is working with the directshow filter you have a entry in the list. That’s the name of our device that we need to pass onto ffmpeg. While you’re there also look for your audio device entry as well. Mine was the truncated word “Stereo Mix (Realtek High Defini” (Yes mine was missing the end of that line). Jot that down somewhere as well. I will show you how to get audio going as well.
6.) So first step is to get video going. Assuming you have a “UScreenCapture” device (You could use another directshow filter if you like, this will work with most of them. I just used the Unreal filter for the heck of it), here is the command to start encoding and sending video:
7.) On the receiving machine you should be able to use vlc, ffmpeg or mplayer to catch the stream. In vlc simply open the Network stream rtp://@:6666 , in ffmpeg you can use the command ffplay -i udp://:6666 or using mplayer you can issue the command mplayer -framedrop -double udp://:6666 .
8.) Now to optionally add sound to the whole thing we can use this command on the encoding machine (instead of step 6). You need to know the device name for your sound card and you probably want to turn the volume down (at least initially) on the decoding machine.
Posted on 18:00, January 15th, 2010 by Many Ayromlou
I just picked one of these babies up from the apple store and after testing it a bit for the past hour, I have one word for it: WOW. This little guy is no gimmick, it’s zippy as hell and it does exactly what they say it would. The details for the device are on Elgato’s Website, but this is just a mini review of the tests I ran against a couple of software encoders.
Here is my setup:
- Mac OSX 10.5.8 with latest updates running on a 2.16Ghz Intel Core 2 Duo Black MacBook w/ 2 GB 667Mhz DDR2 SDRAM.
- Output was done through the Elgato Turbo stick, Mpeg Streamclip encoder and ffmpegX.
- In all cases I’ve tried to produce a single pass h264/x264 file with the same dimensions and settings as the Elgato software preset for ipod best (640×360 @ 24 fps @ 1500 kbps at 80-90% quality).
The results blew my mind:
Here are a couple of full size frames (640×360 px) blown up to 1920×1200 to exaggerate imperfections (click on the pics to see them full size):
- Mpeg Streamclip
- And last but not least all three at the original size (left to right): Elgato Turbo Stick, Mpeg Streamclip, ffmpegX
Best C$179 I’ve spent in a while. It just works.
Posted on 16:49, June 26th, 2008 by Many Ayromlou
Well kids are you ready for todays lesson in transcoding DV video. So first you need a decent machine. I’m using a P4 2.4Ghz oldie that has Firewire on-board and am chewing up 50% CPU for NTSC encoding. Then you need to get Ubuntu 8.04 installed. Once that’s done use the following command to install vlc (Video Lan Client):
The above command (in case you’re wondering) will literally open device zero on the firewire chain and redirect it’s raw output into the VLC program. VLC is told to accept input from a pipe in rawdv format and to transcode it to mpeg4 Video @ 1Mb/s with mpeg1-layer3 audio @ 192 Kb/s.
Once the above command is running you’ll need to go to your receiving machine (the machine who’s IP you supplied in the command above), run VLC and from the File menu choose “Open Network Stream” and go with the default UDP/RTP on port 1234 (or whatever port you chose in the encoder command line).
Another neat thing you can do with your new found opensource goody bag is capture DV from your camera/settop box and save it in mpeg4 format for archival purposes (or mpeg2 for editing maybe). I’m not gonna get into the details, but assuming you’ve done the above commands, skip the encoder command and issue the following command to get your DV stream saved:
Posted on 22:20, November 21st, 2007 by Many Ayromlou
I’ve been trying to figure out a way to do this on the cheap for a long time and I finally figured it out today. This process allows you to grab HDV from a HDV Camera via firewire, feed it into linux, transcode the 25Mb/s mpeg-ts stream to a 4 Mb/s mpeg4 stream (inside a TS). This mpeg4 stream in turn can be viewed at full resolution (1920×1080) on a remote client running just vlc. Here is the prerequisites:
Okay so here we go, follow the steps below to get setup:
Now that you have the chain setup, it’s time to do a quick test and see if the system is working. Issue the following command from a xterm, making sure that the camera is turned on and in “Camera” mode.
If this works you should get a vlc window and be able to see live video from your HDV camera. If you didn’t then stop here and make sure you get this working first.
So now that we have dvgrab working, lets grab that 25Mb/s HDV stream and squish it down to 4Mb/s mpeg4 stream using the following command:
So now you should be able to open up vlc on the receiver machine, goto File/Open Network menu and select UDP/RTP and specify port number 1234. Once you press OK, you should see the video stream on your receiver machine. Audio works as well and is perfectly synced since it’s captured by the HDV camera at the source and travels together with the video at all time. The delay is about 3 seconds.
This is a great way to quickly setup a HD Video Conference between a couple of locations. You could even modify the network portion of the chain to let VLC multicast the HD stream onto your network…..lots of possibilities. Enjoy :-)