ffmpeg - rotating and HD video transcoding example

I do have a video portrait shot (sincerely recommended not to do so ..), into the computer after it is bound to take rotated 90 °, but did not expect such a simple function, try the N non-linear editing software (openshot , pitivi, still lives father of the pit) after that no one can meet my requirements. Either> does not support custom resolution (openshot), either the image imbalance (pitivi), or is unresponsive (lives, feel that the goods are of major non-linear editing workstation tools, and other Cock silk I can not control). Finally, reluctantly, himself google, foreigners still find tricky, a command to save the world:

ffmpeg -i INPUT.AVI -vcodec libx264 -preset slower -crf 18 -threads 4 -acodec copy OUTPUT.MKV

Explain parameters:

 

• -i Be transcoded file
• -vcodec Select the video encoding. Did some searching, compared with MPEG2, MPEG4, etc., H.264 is recognized as the best high-definition encoding format, while the compression ratio is also higher than MPEG4, so I chose to use H.264 (libx264) for video encoding.
• -preset Encoding preset selection, slower = better video quality value can be selected  ultrafast, superfast,  veryfast,  faster,  fast,  medium,  slow,  slower,  veryslow,  placebo. placeboIt is useless values.
• -crf Constant Rate Factor, ranging between 0 to 51, 0 is lossless, the default value is 23, the larger the value, the poorer the overall quality of the video. This parameter is generally between 18 and 28. 18 has reached a visually lossless effect that the human eye can hardly notice the difference and the original film.
• -threads Encoded using threads, CPU core is set a few a few threads as well.
• -vf Filter, we only need to use a rotary filter transpose=2, transposethe filter is preferably 90 ° counterclockwise 0-3,0 and vertical flip, 1 is rotated by 90 ° clockwise, 90 ° counterclockwise rotation of 2, 90 clockwise. 3 ° and flipped vertically.
• -acodec Audio coding, here directly to copyretain the original file audio encoding.
• Finally, set the output file to OUTPUT.MKV

Detailed Description Parameter refer the FFmpeg and x264 Encoding Guide .