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Cambricon^® FFmpeg-MLU

Cambricon^® FFmpeg-MLU supports hardware-accelerated video decoding and encoding using a plain C API on Cambricon MLU hardware platforms.

Requirements

• Supported OS:
  • Ubuntu
  • Centos
  • Debian
• Cambricon MLU Driver:
  • neuware-mlu270-driver-4.0.3 or later.
• Cambricon MLU SDK:
  • neuware-mlu270-1.2.5-1 or later.

Patch and Build FFmpeg-MLU

1. Get FFmpeg sources and patch with the following Git* command:

   git clone https://gitee.com/mirrors/ffmpeg.git -b release/4.2 --depth=1
   cd ffmpeg    
   git apply ../ffmpeg4.2_mlu.patch

2. If you are using CentOS, you need to set LD_LIBRARY_PATH to the proper directory by running the following commands:

   export LD_LIBRARY_PATH=/usr/local/neuware/lib64

3. Run the following commands to configure and build FFmpeg-MLU:

   ./configure --enable-gpl \
               --enable-version3 \
               --enable-mlumpp \
               --extra-cflags="-I/usr/local/neuware/include" \
               --extra-ldflags="-L/usr/local/neuware/lib64" \
               --extra-libs="-lcncodec -lcnrt -ldl"
   make -j

4. If you need a MLU transcode demo with multi-threads, run the following commands:

   make -j examples

5. (Optional) If you need support downscaling with MLU operators, build mluop_plugin and copy libeasyOP.so to the /usr/local/neuware/lib64 folder.

Decoding and Encoding with FFmpeg-MLU

Decoding

Supported video decoding formats are as follows:

• H.264/AVC
  • Codec Name: h264_mludec
• HEVC
  • Codec Name: hevc_mludec
• VP8
  • Codec Name: vp8_mludec
• VP9
  • Codec Name: vp9_mludec
• JPEG
  • Codec Name: mjpeg_mludec

Example

export LD_LIBRARY_PATH=/usr/local/neuware/lib64
./ffmpeg -c:v h264_mludec -i input_file -f null -

Encoding

Supported video encoding formats are as follows:

• H.264/AVC
  • Codec Name: h264_mluenc
• HEVC
  • Codec Name: hevc_mluenc

Example

export LD_LIBRARY_PATH=/usr/local/neuware/lib64
./ffmpeg -i input_file -c:v h264_mluenc <output.h264>

Basic Testing

Encode Baseline Test

./ffmpeg -benchmark -re -i input.mkv -c:v h264_mluenc -f null -

Decode with Scaling

./ffmpeg -y -vsync 0 -c:v h264_mludec -i input_1920x1080.mkv -vf scale=320:240 output_320x240.mp4

1:1 Transcode Without Scaling

./ffmpeg -y -vsync 0 -c:v h264_mludec -i fhd_input.mkv -c:a copy -c:v h264_mluenc -b:v 5M output.mp4

1:N Transcode With Scaling

./ffmpeg -y -vsync 0 -c:v h264_mludec -i fhd_input.mkv -vf scale=1280:720 -c:a copy -c:v h264_mluenc -b:v 2M output1.mp4 -vf scale=640:360 -c:a copy -c:v h264_mluenc -b:v 512K output2.mp4

Quality Testing

This section introduces how to test video quality with PSNR and SSTM.

PSNR

./ffmpeg -i src.h264  -i dst.h264  -lavfi psnr="stats_file=psnr.log" -f null -

SSIM

./ffmpeg -i src.h264  -i dst.h264  -lavfi ssim="stats_file=ssim.log" -f null -

Performance Fine-Tune

This section introduces how to improve the performance.

MLU Decoder

Option name	Type	Description
device_id	int	Select the accelerator card. Supported values range from 0 to INT_MAX. INT_MAX is the total number of accelerator cards minus 1. The default value is 0.
instance_id	int	Select the VPU instance. Supported values are: - Value in the range 0 - 5: Represents VPU instance. - 6: The VPU instance is auto-selected. The default value is 6.
cnrt_init_flag	int	Initialize or destory cnrt context in FFmpeg. Supported values are: - 0: Represents disabled. - 1: Represents enabled. The default value is 1.
input_buf_num	int	Number of input buffers for decoder. Supported values range from 1 to 32. The default value is 5.
output_buf_num	int	Number of output buffers for decoder. Supported values range from 1 to 32. The default value is 6.
stride_align	int	Stride align of output buffers for decoder. Supported values range from 1 to 128, can be 2^(0 - 7). The default value is 1.
output_pixfmt	int	The output pixel format. Supported values are: - 0: Represents NV12. - 1: Represents NV21. - 2: Represents I420. The default value is 0.
resize	string	Resize (width)x(height). Only supports 1/2 and 1/4 for down scaling. The default is null.
trace	int	MLU FFmpeg MLU trace switch. Supported values are: - 0: Represents disabled. - 1: Represents enabled. The default value is 0.

MLU Encoder

Common

Option name	Type	Description
device_id	int	Select the accelerator card. Supported values range from 0 to INT_MAX. INT_MAX is the total number of accelerator cards minus 1. The default value is 0.
instance_id	int	Select the VPU instance. Supported values are: - Value in the range 0 - 1: Represents VPU instance. - 6: The VPU instance is auto-selected. The default value is 6.
cnrt_init_flag	int	Initialize or destory cnrt context in FFmpeg. Supported values are: - 0: Represents disabled. - 1: Represents enabled. The default value is 1.
input_buf_num	int	Number of input buffers for encoder. Supported values range from 1 to 32. The default value is 3.
output_buf_num	int	Number of output buffers for encoder. Supported values range from 1 to 32. The default value is 5.
trace	int	MLU FFmpeg debug switch. Supported values are: - 0 Represents disabled. - 1: Represents enabled. The default value is 0.
init_qpP	int	Initial QP value for P frame, set P frame QP. Supported values range from -1 to 51. The default value is -1.
init_qpI	int	Initial QP value for I frame, set I frame QP. Supported values range from -1 to 51. The default value is -1.
init_qpB	int	Initial QP value for B frame, set B frame QP. Supported values range from -1 to 51. The default value is -1.
qp	int	Constant QP rate control method, same as FFmpeg cqp. Supported values range from -1 to 51. The default value is -1.
vbr_minqp	int	Variable bitrate mode with MinQP, same as FFmepg qmin. Supported values range from -1 to 51. The default value is -1.
vbr_maxqp	int	Variable bitrate mode with MaxQP, same as FFmpeg qmax. Supported values range from -1 to 51. The default value is -1.

H264

Option name	Type	Description
profile	const	Set the encoding profile. Supported values are: baseline, main, high, and high444p. The default value is high.
level	const	Set the encoding level restriction. Supported values are: in the range 1 - 5.1, or auto. The default value is 4.2.
coder	const	Set the encoding entropy mode. Supported values are: cabac and cavlc. The default value is cavlc.

HEVC

Option name	Type	Description
profile	const	Set the encoding profile. Supported values are: main, main_still, main_intra, and main10. The default value is main.
level	const	Set the encoding level restriction. Supported values are: in the range 1 - 6.2, or auto. The default value is 1.