ffmpeg concat+scale2ref，还原framerate

Question

我尝试了一个movie1.mp4的副本，并将其重命名为movie2.mp4，以确保它们完全相同，并得到了相同的问题。

Input #0, lavfi, from 'color':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 320x240 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from './1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:02.47, start: 0.000000, bitrate: 6737 kb/s
    Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 6567 kb/s, 30 fps, 30 tbr, 90k tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #1:1(und): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 160 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #2, mov,mp4,m4a,3gp,3g2,mj2, from './2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:02.47, start: 0.000000, bitrate: 6737 kb/s
    Stream #2:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 6567 kb/s, 30 fps, 30 tbr, 90k tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #2:1(und): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 160 kb/s (default)
    Metadata:
      handler_name    : SoundHandler

输出文件：

[libx264 @ 000001a689d44180] using SAR=1/1
[libx264 @ 000001a689d44180] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 000001a689d44180] profile High, level 4.0, 4:2:0, 8-bit
[libx264 @ 000001a689d44180] 264 - core 160 - 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=24 lookahead_threads=4 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 './out.mp4':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
    Metadata:
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      encoder         : Lavc58.54.100 aac
frame=  124 fps= 72 q=-1.0 Lsize=    3842kB time=00:00:04.84 bitrate=6502.6kbits/s speed=2.79x

下面是我的命令行：

ffmpeg -y -f lavfi -i color -i ./1.mp4 -i ./2.mp4 -filter_complex_script ./3.txt  ./out.mp4

[0][1]scale2ref[canvas][vid1];[canvas][2]scale2ref='max(iw,main_w)':'max(ih,main_h)'[canvas][vid2];[canvas]split=2[canvas1][canvas2];[canvas1][vid1]overlay=x='(W-w)/2':y='(H-h)/2':shortest=1[vid1];[canvas2][vid2]overlay=x='(W-w)/2':y='(H-h)/2':shortest=1[vid2];[vid1][vid2]concat=n=2:v=1,setsar=1

null

Answer 1

覆盖过滤器将使用第一个输入的帧速率。因此，将滤色器帧速率（例如color=r=30)设置为您需要的任何速率。

没有自动选择“最佳”帧率的选项。它只是做你让它做的事。

您可以通过使用ffprobe来实现自动化，以获取每个输入的帧速率，并使用脚本来决定要做什么。请注意，VFR输入可能会使这种方法复杂化，最简单的方法是只强制一个一致的帧速率。FFMPEG将删除或复制帧，以适应您所需的帧速率。