ffmpeg

Option	Description
-encoders	show available encoders
-h encoder=<encoder>	show help about the <encoder>
-h decoder=<decoder>	show help about the <decoder>
-hide_banner	hide banner

Input

• place option before -i

Option	Description
-vsync 0	prevent duplicate and extra frames (fix sync issue?)
-i <URL>	Input stream

Output

• place option before <output URL>

Option	Description
-c:a <codec>	Select audio encoder
-c:v <codec>	Select video encoder
-c <codec>	Select encoder

Codec

• copy

Bit Rate

CBR

Constant Bit Rate

VBR

Variable Bit Rate

CRF

Constant Rate Factor

Ref

• Good for offline video
• Recommended CRF ≈ 20 ~ 30

AVC

Advanced Video Coding

• H.264

HEVC

High Efficiency Video Coding

• H.265

Video Encoder

libx264

Software H.264

h264_nvenc

NVIDIA NVENC H.264 encoder

libx265

Software H.265

Option	Description
-crf <CRF>	Constant Rate Factor

hevc_nvenc

NVIDIA NVENC HEVC encoder

• -preset {slow|medium|fast|p1|...|p7}
  • p1 fastest
  • p7 slowest

Hardware accelerator

Ref

Option	Description
-hwaccel cuda	chooses appropriate hw accelerator
-hwaccel_output_format cuda	keeps the decoded frames in GPU memory

Pixel format

Ref

Show pixel format

ffmpeg -pix_fmts

Common format

Option	Description
-vf format=<format>	set pixel format
yuv420p	8-bit 4:2:0
yuv420p10le	10-bit 4:2:0

Extract subtitle

ffmpeg -an -vn -i <video.mkv> -map 0:s:0 <sub.srt>

Option	Description
-an -vn	no audio, no video (faster)
-map 0	the first input
:s	subtitle
:s:0	the first subtitle