Category Archive: Articles
Just several days after version 0.8.18 was released, I implemented two new features as will be introduced below. If you are interested in them, you can upgrade to 0.8.18.5333 with update package from 0.8.18.5330. 1. Multi-Pass CRF - Using CRF mode in the first pass of multi-pass mode A check box labeled Multi-Pass CRF was added on the right of Rate Mode option droplist. By enabling it when 2-pass or 3-pass mode is chosen, video encoder (currently only x264) will do the first pass in CRF mode and a bitrate will be determined in result of the quality value specified. In 2nd pass or 3rd pass (if there is one), the encoder will still encode in the normal way but with the target bitrate set as is obtained in the first pass. This feature is especially useful to users who like multi-pass encoding but still want the bitrate to be determined by the encoder (as if in CRF mode) according to the video content (resolution, frame rate, motion complexicty, image details etc.) to be encoded. Read the rest of this entry >>
For people who loves transcoding (like me), they like to watch the progress of their transcodings. So why not make the progress look cooler. A year ago, I was developing a dashboard software for my car. That piece of software wasn't getting famous like MediaCoder. Fortunately my work wasn't all wasted. Today I moved my dashboard rendering engine into MediaCoder. A new preview mode named Dashboard mode was added, in which, a dashboard with some live statistics will be shown side by side with the video frame being transcoded. Read the rest of this entry >>
MK802 is a popular ARM based super micro computer which can plug directly into any HDMI output for an on the go media player, internet browser, game machine or for general use. It features 1.0GHz Cortex-A8 CPU and 500MHz GPU, 1GB DDR3 memory and 4GB flash storage. The stock Android can be replaced with Ubuntu Linux. Read the rest of this entry >>
After suddenly getting interested in time-lapse video, I added the time-lapse video recording feature in MediaCoder with a USB camera or any other DirectShow video capture device. Here please see a demo I just made. Read the rest of this entry >>
Today I performed a benchmarking test with MediaCoder iPhone Edition which has got improved support for Intel MSDK recently, by transcoding the same 720p H.264 MKV file to a MP4 file of iPhone 4 profile. In order to obtain transcoded videos with near visual quality, x264 was set to fast preset and Intel MSDK encoder was set to balanced mode. The difference in transcoding speed and CPU utilization is significant. With x264, the CPU utilization is near 100% and the overall transcoding speed is approximately 3.4x (versus playback speed). When using Intel MSDK encoder, with computation off-loaded to CPU built-in GPU, the CPU utilization is near 50% and the overall speed is about 7.9x, which is 2.3 times of that of x264.
MediaCoder has supported H.264 High 10 Profile (10-bit color depth) encoding since quite a long time ago. However, due to the lack of good and free decoder and player for this profile, I haven't seriously test with it until today. I encoded a 720p video clip in Hi10P at 1Mbps (really low for HD content) and played the encoded content with VLC 2.0.1. The result is quite impressive.
Recently I've been spending some time improving MediaCoder's support for Intel MSDK encoder, the GPU acclerated H.264 and MPEG-2 encoder from the chip giant. A new revision of MediaCoder (before I can finish and implement all the major improvements in my mind and release MediaCoder 2012), is released containing several improvements including slight performance boost when using Intel MSDK encoder to perform hardware accelerated encoding. Actually the performance of Intel MSDK encoder is astonishing. This comes from the good implementation of the underlying multimedia facilities of Intel Media SDK framework, as well as the multi-threaded design of MediaCoder, espeically its built-in large circulla frame buffer used for efficiently transferring raw audio and video data from decoder to encoder. Here I give some tips for using Intel MSDK encoder in MediaCoder. Read the rest of this entry >>
MediaCoder started to adopt Intel Media SDK in early 2010. By using the GPU accelerated encoder provided by the SDK, MediaCoder achieved significant increase in H.264 and MPEG-2 encoding speed, which reaches up to 5 times faster than encoding with x264 or FFmpeg. Being able to off load the heavy encoding computations to GPU, MediaCoder can better use the CPU to perform I/O operations, task management，audio decoding/encoding, stream multiplexing and most importantly video decoding which is also computational complex and obviously there are too many long-existing or legacy formats to have the GPU implementation for all of them. Comparing to nVidia's CUDA accelerated H.264 encoder, Intel's implementation provides much better visual quality, which makes the GPU accelerated video encoding acceptable by industrial customers, especially those of MediaCoder KTV Edition who perform massive transcoding for serious business use.