Some H.264 stream in MKV container is already iPhone or iPad playable. In such case, we only need to convert the audio format and remux the video stream with converted audio stream into MP4 container in order to let iPhone or iPad play it. This can save us significant amount of time for transcoding.

Since 0.7.5.4710, MediaCoder has added support for video capture device as a transcoding task. In other word, the video from a webcam or other DirectShow capture device can be encoded directly in MediaCoder now. You can see a new “Add Capture Device” when clicking Add button. Read the rest of this entry »

Finally we can have multiple files processed simultaneously in MediaCoder with the new job-level parallelization support. Those who have a processor with 8 or 16 cores can now unleash the power of their processor. As MediaCoder is not just a simple GUI front-end which only invokes a command line encoder wait sits there waiting for the encoder to complete, instead it distribute frame data and the audio samples from decoders to encoders, the job-level parallelization is not that easy to add from the old design. In order to add this feature, large amount of the code has been rewritten. Finally it works after several weeks’ efforts, though it might still be experimental for a while. The number of the maximum parallelized jobs is limited to 4 at the moment. So feedbacks welcomed!

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The latest MediaCoder iPod Edition (version 0.7.3.4630) has added support for iPad video format. The 64-bit version of this edition is also available.



iPad Supported Video Formats

• H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats
• MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats
• Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format

Head for the page of MediaCoder iPhone/iPod/iPad Edition

In the build 4560, you can easily set processor affinity for audio/video decoder and encoder. By clicking the check boxes which represent each core of your processor. If you have a quad-core processor, you will se 4 check boxes enabled and selected by default. Unticking a checkbox will cause a core not to be used by chosen decoder or encoder.  If you processor has many cores, this will be useful, as you can allocate different cores for different use, or preserve some cores free for your other tasks. Some tips:

• Even if all cores are selected, they are not necessarily be 100% utilized during transocidng. This depends on the multi-threading support in decoder or encoder.
• A started job will not be affected by the change of the affinity option, unlike the change of the prioirty option.

MediaCoder is improving all the time even if the version number keep the same. This time there are some major changes, so let’s increase the number after nearly 10 months. I’ve spent lots of time to prepare the release of 0.7. Let me briefly recall what has been changed. Read the rest of this entry »

Item grouping feature is added since build 4260. By selecting multiple items in the list and choosing Group from menu (right click an item to pop up), the items will be marked as the same group ID. During processing, they will be joined into one file. The grouping feature also prepares for the upcoming support for multi-track transcoding. The join mode is removed since then.

Item grouping in MediaCoder

Windows Media encoding is proved in the latest build 4224. Previously, when MediaCoder encoding Windows Media with Microsoft Windows Media Format component, audio and video data are encoded and muxed in one thread (despite the possibility that the component may have its multi-threading approach underlying). Now audio and video are encoded in separated threads, and the encoded streams are multiplexed after encoding process. This will eliminate some WMV encoding problem and bring in better encoding performance on dual-core processors as well as better container flexibility. If you experience problems with the new mechansim, please report.