KSC265codec(v2.6.1.3)

It should be noted that, the libraries used in our ios/andriod demos have expiration time.

ENCODER

Usage: command line examples

AppEncoder_x64 -i p_3840x2160_50.yuv -preset ultrafast/veryfast/slow/veryslow -latency offline -wdt 3840 -hgt 2160 -fr 50 -rc 1 -br 20000 -iper 128 -b test.265
AppEncoder_x64 -i p_3840x2160_50.yuv -preset ultrafast/veryfast/slow/veryslow -latency offline -wdt 3840 -hgt 2160 -fr 50 -rc 0 -qp 27 -iper 128 -b test.265
AppEncoder_x64 -i p_3840x2160_50.yuv -preset ultrafast/veryfast/slow/veryslow -latency offline -wdt 3840 -hgt 2160 -fr 50 -rc 3 -crf 24 -iper 128 -b test.265

Basic parameters:

-preset [preset_value],

which specifies the encoding speed by the character string [preset_value], among strings of "superfast", "veryfast", "fast", "medium", "slow", "veryslow" and "placebo".

-latency [latency_value],

which specifies the encoding latency by the character string [lactency_value], among strings of "zerolatency", "livestreaming", "offline". Note that, in the presets of ultrafast~veryfast, the latency under "livestreaming" and "offline" are the same.

-i [input_filename],

which specifies the address of the input YUV file in 4:2:0 sampling format by a character string [input_filename].

-wdt [width],

which specifies the image width of the input video by a positive integer value [width].

-hgt [height],

which specifies the image height of the input video by a positive integer value [height].

-fr [framerate],

which specifies the frame rate of the input video by a positive integer value [framerate].

-iper [intraperiod],

which specifies the maximum distances between consecutive I pictures by a positive integer value [intraperiod].

-rc [rctype],

which specifies the rate control type by the positive integer value [rctype] valuing among values 0(fixed qp), 1(cbr), 2(abr) and 3(crf). There are four cases:

• -br [bitrate] should be followed. If [rctype] equals to 1 or 2, a parameter -br [bitrate] should be followed and specifies the target encoding bit-rate by the positive value [bitrate] (kbps,kilo bit rate per second).
• -qp [qp_value] should be followed. If [rctype] equals to 0, a parameter -qp [qp_value] should be followed and specifies the target encoding quantization parameter by the positive value [qp_value] ranging from 0 to 51.
• -crf [crf_value] should be followed. If [rctype] equals to 3, a parameter -crf [crf_value] should be followed and specifies the target crf parameter by the positive value [crf_value] ranging from 0 to 51.

-b [stream_filename],

which specifies the address of the output stream file in HEVC/H.265 format by a character string [stream_filename]. Default: no stream is output.

Optional parameters:

-v or -V [version],

which is utilized to print the version and copyright of the encoder.

-psnr [psnrcalc],

which specifies psnr calculation method by a non-negative value [psnrcalc], and

• 0 (as a default value) means disabling psnr calculation,
• 1 means enabling psnr calculation and outputing the overall psnr result.
• 2 means enabling psnr calculation and outputing psnr info for each frame.

-o [reconstructYUV],

which specifies the address of the reconstrcuted yuv file in 4:2:0 format by a character string [reconstructYUV]. Default: no reconstructed YUV file is output.

-frms [frame_no],

which specifies the number of frames to be encoded for the input video by a positive integer value [frame_no]. Default: [frame_no] = -1, when all input frames are encoded.

-threads [thread_no],

which specifies the number of threads used to encode the input video by a non-negative value [thread_no]. Default: [thread_no] = 0, when all available threads can be utilized.

-bframes[value1], -vbv-maxrate [value2] , -vbv-bufsize[value3],

which specifies similar meanings as similar values defined in x264

DECODER

Usage: command line examples

AppDecoder_x64.exe -b test.265 -o test.yuv -threads 2

Basic parameters:

-v or -V [version]

which specifies the decoder version and copyright.

-b [bitstream],

which specifies input bit-stream file by a character string [bitstream].

Optional parameters:

-o [output],

which specifies the decoded yuv file name by a character string [output].

-threads [threadnum],

which specifies the number of threads used for decoding process by a non-negative value [threadnum]. Default: [threadnum] = 0, when all available threads can be utilized.

Performance of decoder

KSC265 decoder is compared with openHEVC in ffmpeg on ARM64@Andriod, ARM64@iOS and x86 platforms.

On average, as above table shows, KSC265 decoder can achieve more than 2/2.5 times the speed of openHEVC in ffmpeg on x86/ARM, and details can be found in the excels for decoding performance. Moreover, as following table shows, the decoding speed of KSC265 now can well support the 1080p@25fps applications.

Performance of encoder

KSC265 encoder is firstly compared with X265-v2.4, X264 and vp9 on Win7@i7-4790@4threads using following parameters:

x264.exe -o out.264 BQSquare_416x240_60.yuv --input-res 416x240 --preset [superfast|veryfast|slow|placebo] --fps [framerate] --profile high --aq-mode 0 --no-psy --psnr  --bitrate [btrNumber] --threads 1/0 --keyint [framerate * 10] --frames 1000000
AppEncoder_x64.exe -b out.265 -i BQSquare_416x240_60.yuv -preset [veryfast|slow|veryslow] -threads 1/0 -psnr 2 -rc 1 -br [btrNumber] -frms 1000000 -iper [framerate * 10]
x265.exe -o out.265 --input BQSquare_416x240_60.yuv --input-res 416x240 --preset [ultrafast|ultrafast|slow|veryslow] --fps [framerate] --aq-mode 0 --no-psy-rd --no-psy-rdoq  --psnr  --bitrate [btrNumber] --frame-threads [1|0] --no-wpp/--wpp --keyint [framerate * 10] --frames 1000000
vpxenc.exe --codec=vp9 --passes=1 --[rt|goog|best] --fps=[framerate]/1 --i420 --end-usage=vbr --target-bitrate=[btrNumber] --kf-max-dist=[framerate * 10] --cpu-used=8 --threads=[1|4] --psnr -w 416 -h 240 -o out.vp9 BQSquare_416x240_60.yuv --frame-parallel=0

Then on test sequences of JCTVC CLASS-A ~ CLASS-E, and one class of game videos@30fps, compared to x264(20161020), x265-v2.4 and vp9 in the speed form of encoded frames per second (fps), the average performance of KS265 can be summarized by the follows.

Secondly, then on test sequences of JCTVC CLASS-A ~ CLASS-E, and one class of showself videos@15fps, compared to x264(20161020), x265-v2.4 and vp9 in the speed form of encoded frames per second (fps), the average performance of KS265 on OPPOR9s@1thread and ipad min2 @1thread can be summarized by the follows.

The details are described in the excel document.