转自：https://brokenpipe.wordpress.com/2016/10/07/ffmpeg-h-264-constant-bitrate-cbr-encoding-for-iptv/
Copy From: https://brokenpipe.wordpress.com/2016/10/07/ffmpeg-h-264-constant-bitrate-cbr-encoding-for-iptv/
Example command using a single-frame VBV:
ffmpeg -i <input> -r 25 -c:v libx264 -x264opts nal-hrd=cbr:force-cfr=1 -b:v 2500k -minrate 2500k -maxrate 2500k -bufsize 100k output.ts
where:
nal-hrd=cbr | set the hypothetical reference decoder (HRD) to CBR and pack the bitstream to the specified bitrate |
force-cfr=1 | force constant framerate timestamp generation |
-b:v | the video bitrate |
-minrate | same as the video bitrate for constant bitrate |
-bufsize | the video buffering verifier (VBV) buffer size, set for capped frame-size encoding (bufsize = bitrate / framerate) |
Additional notes:
- for even lower latency use -tune zerolatency and intra-refresh.
- single-frame VBV can be inaccurate with small frame-sizes and multi-threading. If the encoder reports many VBV underflows try setting -threads 1
