ffmpeg设置视频 tbr、tbn、tbc

本文主要是介绍ffmpeg设置视频 tbr、tbn、tbc，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

时间基相关的定义

tbr 表示帧率，该参数倾向于一个基准，往往tbr跟fps相同。(the time base in AVStream that has come from the container)
tbn 表示视频流 timebase（时间基准），比如ts流的timebase 为90000，flv格式视频流timebase为1000 (the time base in AVCodecContext for the codec used for a particular stream)
tbc 表示视频流codec timebase ，对于264码流该参数通过解析sps间接获取（通过sps获取帧率）(tbr is guessed from the video stream and is the value users want to see when they look for the video frame rate)

时间基相关的设置

分别设置tbn为80k、tbc为45、tbr为25
ffmpeg -hide_banner -i input.mp4 -c:v libx264 -time_base 1/80000 -enc_time_base 1/45 -r 25 -f mp4 output.mp4 -y
output视频输出信息
Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 720x1280, q=-1--1, 25 fps, 80k tbn, 45 tbc (default)
详细的转码日志

ffmpeg -hide_banner -i input.mp4 -c:v libx264 -time_base 1/80000 -enc_time_base 1/45 -r 25 -f mp4 output.mp4 -y
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':Metadata:major_brand     : qt  minor_version   : 0compatible_brands: qt  creation_time   : 2020-08-03T12:32:30.000000ZDuration: 00:00:20.54, start: 0.000000, bitrate: 4446 kb/sStream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 126 kb/s (default)Metadata:creation_time   : 2020-08-03T12:32:30.000000Zhandler_name    : Core Media AudioStream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 720x1280, 4316 kb/s, 16.11 fps, 16 tbr, 600 tbn, 1200 tbc (default)Metadata:creation_time   : 2020-08-03T12:32:30.000000Zhandler_name    : Core Media Videoencoder         : H.264
Stream mapping:Stream #0:1 -> #0:0 (h264 (native) -> h264 (libx264))Stream #0:0 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x7fa61d010800] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x7fa61d010800] profile High, level 3.1, 4:2:0, 8-bit
[libx264 @ 0x7fa61d010800] 264 - core 159 r2999 296494a - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=18 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'output.mp4':Metadata:major_brand     : qt  minor_version   : 0compatible_brands: qt  encoder         : Lavf58.29.100Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 720x1280, q=-1--1, 25 fps, 80k tbn, 45 tbc (default)Metadata:creation_time   : 2020-08-03T12:32:30.000000Zhandler_name    : Core Media Videoencoder         : Lavc58.54.100 libx264Side data:cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)Metadata:creation_time   : 2020-08-03T12:32:30.000000Zhandler_name    : Core Media Audioencoder         : Lavc58.54.100 aac
frame=  926 fps=213 q=-1.0 Lsize=    3969kB time=00:00:20.51 bitrate=1585.4kbits/s dup=595 drop=0 speed=4.71x    
video:3614kB audio:321kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.865847%
[libx264 @ 0x7fa61d010800] frame I:8     Avg QP:18.62  size: 56722
[libx264 @ 0x7fa61d010800] frame P:233   Avg QP:22.08  size: 11749
[libx264 @ 0x7fa61d010800] frame B:685   Avg QP:25.08  size:   743
[libx264 @ 0x7fa61d010800] consecutive B-frames:  1.1%  0.4%  1.3% 97.2%
[libx264 @ 0x7fa61d010800] mb I  I16..4: 13.0% 32.4% 54.6%
[libx264 @ 0x7fa61d010800] mb P  I16..4:  2.1%  4.1%  0.9%  P16..4: 42.2%  9.5%  6.5%  0.0%  0.0%    skip:34.7%
[libx264 @ 0x7fa61d010800] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8: 19.6%  0.2%  0.0%  direct: 0.2%  skip:79.9%  L0:48.1% L1:51.0% BI: 0.8%
[libx264 @ 0x7fa61d010800] 8x8 transform intra:49.1% inter:72.7%
[libx264 @ 0x7fa61d010800] coded y,uvDC,uvAC intra: 53.5% 62.9% 12.8% inter: 6.0% 7.8% 0.1%
[libx264 @ 0x7fa61d010800] i16 v,h,dc,p: 40% 24% 24% 12%
[libx264 @ 0x7fa61d010800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 12% 40%  4%  4%  6%  3%  4%  3%
[libx264 @ 0x7fa61d010800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 14% 18%  7%  8%  9%  5%  6%  3%
[libx264 @ 0x7fa61d010800] i8c dc,h,v,p: 50% 18% 27%  6%
[libx264 @ 0x7fa61d010800] Weighted P-Frames: Y:3.4% UV:0.4%
[libx264 @ 0x7fa61d010800] ref P L0: 66.2% 16.2% 12.6%  4.9%  0.2%
[libx264 @ 0x7fa61d010800] ref B L0: 91.8%  6.7%  1.5%
[libx264 @ 0x7fa61d010800] ref B L1: 93.2%  6.8%
[libx264 @ 0x7fa61d010800] kb/s:1438.45
[aac @ 0x7fa61d012000] Qavg: 235.295