Answers.Body: <p>you have to specify both an input and an output framerate, right now you are only setting the input framerate. Try</p>
  <pre><code>find dir/ -iname '*.jpg' | xargs cat | ffmpeg -f image2pipe -r 20 -i - -s 1080x720 -r 20 -pix_fmt yuv420p out.mkv
  </code></pre>
  <p>hope this works</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-11-06T13:50:03.603Z
Answers.Text: I still obtain a 6 seconds video with your command
Answers.UserDisplayName: user16945608
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-10-29T09:46:03.933Z
Answers.LastActivityDate: 2021-11-01T17:42:51.117Z
Answers.LastEditDate: 2021-11-01T17:42:51.117Z
Answers.UserDisplayName: thomas
Body: <p>I have 40 <code>.jpg</code> in my <code>dir</code> folder and want to create a video at 20fps from them. I've tried the following command:</p>
  <p><code>find dir/ -iname '*.jpg' | xargs cat | ffmpeg -f image2pipe -framerate 20 -i - -s 1080x720 -pix_fmt yuv420p out.mkv</code></p>
  <p>I expect to obtain a 2 seconds video (40 images / 20 fps) but I get a 6 seconds video. Here is the output of ffmpeg:</p>
  <pre><code>[image2pipe @ 0x564d225dd940] Stream #0: not enough frames to estimate rate; consider increasing probesize
  Input #0, image2pipe, from 'pipe:':
    Duration: N/A, bitrate: N/A
    Stream #0:0: Video: mjpeg (Baseline), yuvj422p(pc, bt470bg/unknown/unknown), 6000x4000, 20 fps, 20 tbr, 20 tbn, 20 tbc
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (mjpeg (native) -&gt; h264 (libx264))
  [swscaler @ 0x564d22b94b00] deprecated pixel format used, make sure you did set range correctly
  [libx264 @ 0x564d225e3180] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  [libx264 @ 0x564d225e3180] profile High, level 3.1, 4:2:0, 8-bit
  [libx264 @ 0x564d225e3180] 264 - core 161 r3039 544c61f - H.264/MPEG-4 AVC codec - Copyleft 2003-2021 - 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=6 lookahead_threads=1 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=20 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, matroska, to 'out.mkv':
    Metadata:
      encoder         : Lavf58.76.100
    Stream #0:0: Video: h264 (H264 / 0x34363248), yuv420p(tv, bt470bg/unknown/unknown, progressive), 1080x720, q=2-31, 20 fps, 1k tbn
      Metadata:
        encoder         : Lavc58.134.100 libx264
      Side data:
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
  frame=    1 fps=0.0 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 3 times
  frame=    5 fps=0.0 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   11 fps=9.9 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d237e33c0] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 4 times
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
  frame=   17 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   23 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 4 times
  [swscaler @ 0x564d247610c0] deprecated pixel format used, make sure you did set range correctly
  frame=   29 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   35 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 1 times
  [swscaler @ 0x564d26bb8f80] deprecated pixel format used, make sure you did set range correctly
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 2 times
  frame=   41 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   47 fps=9.9 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   53 fps=9.8 q=28.0 size=       1kB time=00:00:00.00 bitrate=5024.0kbits/s speed=0.000184x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   59 fps=9.7 q=28.0 size=       1kB time=00:00:00.30 bitrate=  16.7kbits/s speed=0.0496x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   65 fps=9.7 q=28.0 size=       1kB time=00:00:00.60 bitrate=   8.4kbits/s speed=0.0894x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   71 fps=9.7 q=28.0 size=       1kB time=00:00:00.90 bitrate=   5.6kbits/s speed=0.123x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   77 fps=9.7 q=28.0 size=       1kB time=00:00:01.20 bitrate=   4.2kbits/s speed=0.151x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   83 fps=9.7 q=28.0 size=       1kB time=00:00:01.50 bitrate=   3.3kbits/s speed=0.175x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   89 fps=9.7 q=28.0 size=       1kB time=00:00:01.80 bitrate=   2.8kbits/s speed=0.196x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   95 fps=9.7 q=28.0 size=       1kB time=00:00:02.10 bitrate=   2.4kbits/s speed=0.213x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=  101 fps=9.7 q=28.0 size=       1kB time=00:00:02.40 bitrate=   2.1kbits/s speed=0.23x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=  107 fps=9.7 q=28.0 size=       1kB time=00:00:02.70 bitrate=   1.9kbits/s speed=0.244x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=  113 fps=9.7 q=28.0 size=       1kB time=00:00:03.00 bitrate=   1.7kbits/s speed=0.258x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=  119 fps=9.7 q=28.0 size=       1kB time=00:00:03.30 bitrate=   1.5kbits/s speed=0.269x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
  frame=  120 fps=8.6 q=-1.0 Lsize=    1338kB time=00:00:05.85 bitrate=1873.8kbits/s speed=0.419x    
  video:1337kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.115425%
  [libx264 @ 0x564d225e3180] frame I:2     Avg QP:22.50  size: 53106
  [libx264 @ 0x564d225e3180] frame P:40    Avg QP:23.81  size: 17895
  [libx264 @ 0x564d225e3180] frame B:78    Avg QP:26.09  size:  7002
  [libx264 @ 0x564d225e3180] consecutive B-frames:  1.7% 16.7% 55.0% 26.7%
  [libx264 @ 0x564d225e3180] mb I  I16..4:  7.6% 74.5% 17.9%
  [libx264 @ 0x564d225e3180] mb P  I16..4:  2.0% 12.3%  2.5%  P16..4: 43.7% 12.6%  5.6%  0.0%  0.0%    skip:21.3%
  [libx264 @ 0x564d225e3180] mb B  I16..4:  0.8%  3.1%  0.4%  B16..8: 35.0%  2.9%  0.5%  direct: 3.7%  skip:53.5%  L0:35.9% L1:61.7% BI: 2.4%
  [libx264 @ 0x564d225e3180] 8x8 transform intra:72.9% inter:80.7%
  [libx264 @ 0x564d225e3180] coded y,uvDC,uvAC intra: 63.5% 86.3% 57.4% inter: 14.6% 31.4% 3.4%
  [libx264 @ 0x564d225e3180] i16 v,h,dc,p: 27% 24% 10% 38%
  [libx264 @ 0x564d225e3180] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 16% 16%  7% 10% 10%  9%  8%  8%
  [libx264 @ 0x564d225e3180] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 16% 13%  7% 12% 10% 10%  7%  5%
  [libx264 @ 0x564d225e3180] i8c dc,h,v,p: 45% 23% 21% 12%
  [libx264 @ 0x564d225e3180] Weighted P-Frames: Y:52.5% UV:50.0%
  [libx264 @ 0x564d225e3180] ref P L0: 49.9% 20.3% 12.0%  9.1%  8.7%
  [libx264 @ 0x564d225e3180] ref B L0: 74.9% 17.1%  8.0%
  [libx264 @ 0x564d225e3180] ref B L1: 97.6%  2.4%
  [libx264 @ 0x564d225e3180] kb/s:1824.23
  </code></pre>
  <p>Here is some info about the <code>out.mkv</code> file:</p>
  <pre><code>Format                                   : Matroska
  Format version                           : Version 4
  File size                                : 850 KiB
  Duration                                 : 6 s 0 ms
  Overall bit rate                         : 1 160 kb/s
  ...
  Format settings, Reference frames        : 4 frames
  Codec ID                                 : V_MPEG4/ISO/AVC
  Duration                                 : 6 s 0 ms
  Bit rate                                 : 1 137 kb/s
  Width                                    : 1 080 pixels
  Height                                   : 720 pixels
  Display aspect ratio                     : 3:2
  Frame rate mode                          : Constant
  Frame rate                               : 20.000 FPS
  Color space                              : YUV
  Chroma subsampling                       : 4:2:0
  Bit depth                                : 8 bits
  Scan type                                : Progressive
  Bits/(Pixel*Frame)                       : 0.073
  </code></pre>
  <p>I've tried different strategies with the <code>-r</code> option, but I cannot get my 2 seconds video at 20 fps. Can you see what going on?</p>
  <p>Also I would like to keep a <code>image2pipe</code> solution instead of a <code>image2</code> solution.</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-09-19T04:07:37.360Z
Comments.Text: Share full log.
Comments.UserDisplayName: Gyan
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-09-19T14:46:03.700Z
Comments.Text: @Gyan I edited the post with the full ffmpeg log
Comments.UserDisplayName: user16945608
Tags: <ffmpeg><linux>
Title: How to obtain the correct framerate with ffmpeg image2pipe format?
UserDisplayName: user16945608
ThreadText: # How to obtain the correct framerate with ffmpeg image2pipe format?
  
  (Asked by: username_0 on 2021-09-18)
  
  I have 40 `.jpg` in my `dir` folder and want to create a video at 20fps from them. I've tried the following command:
  
  `find dir/ -iname '*.jpg' | xargs cat | ffmpeg -f image2pipe -framerate 20 -i - -s 1080x720 -pix_fmt yuv420p out.mkv`
  
  I expect to obtain a 2 seconds video (40 images / 20 fps) but I get a 6 seconds video. Here is the output of ffmpeg:
  
  ```
  [image2pipe @ 0x564d225dd940] Stream #0: not enough frames to estimate rate; consider increasing probesize
  Input #0, image2pipe, from 'pipe:':
    Duration: N/A, bitrate: N/A
    Stream #0:0: Video: mjpeg (Baseline), yuvj422p(pc, bt470bg/unknown/unknown), 6000x4000, 20 fps, 20 tbr, 20 tbn, 20 tbc
  Stream mapping:
    Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
  [swscaler @ 0x564d22b94b00] deprecated pixel format used, make sure you did set range correctly
  [libx264 @ 0x564d225e3180] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  [libx264 @ 0x564d225e3180] profile High, level 3.1, 4:2:0, 8-bit
  [libx264 @ 0x564d225e3180] 264 - core 161 r3039 544c61f - H.264/MPEG-4 AVC codec - Copyleft 2003-2021 - 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=6 lookahead_threads=1 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=20 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, matroska, to 'out.mkv':
    Metadata:
      encoder         : Lavf58.76.100
    Stream #0:0: Video: h264 (H264 / 0x34363248), yuv420p(tv, bt470bg/unknown/unknown, progressive), 1080x720, q=2-31, 20 fps, 1k tbn
      Metadata:
        encoder         : Lavc58.134.100 libx264
      Side data:
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
  frame=    1 fps=0.0 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 3 times
  frame=    5 fps=0.0 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   11 fps=9.9 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d237e33c0] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 4 times
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
  frame=   17 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   23 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 4 times
  [swscaler @ 0x564d247610c0] deprecated pixel format used, make sure you did set range correctly
  frame=   29 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   35 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 1 times
  [swscaler @ 0x564d26bb8f80] deprecated pixel format used, make sure you did set range correctly
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 2 times
  frame=   41 fps= 10 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   47 fps=9.9 q=0.0 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   53 fps=9.8 q=28.0 size=       1kB time=00:00:00.00 bitrate=5024.0kbits/s speed=0.000184x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   59 fps=9.7 q=28.0 size=       1kB time=00:00:00.30 bitrate=  16.7kbits/s speed=0.0496x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   65 fps=9.7 q=28.0 size=       1kB time=00:00:00.60 bitrate=   8.4kbits/s speed=0.0894x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   71 fps=9.7 q=28.0 size=       1kB time=00:00:00.90 bitrate=   5.6kbits/s speed=0.123x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   77 fps=9.7 q=28.0 size=       1kB time=00:00:01.20 bitrate=   4.2kbits/s speed=0.151x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   83 fps=9.7 q=28.0 size=       1kB time=00:00:01.50 bitrate=   3.3kbits/s speed=0.175x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   89 fps=9.7 q=28.0 size=       1kB time=00:00:01.80 bitrate=   2.8kbits/s speed=0.196x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=   95 fps=9.7 q=28.0 size=       1kB time=00:00:02.10 bitrate=   2.4kbits/s speed=0.213x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=  101 fps=9.7 q=28.0 size=       1kB time=00:00:02.40 bitrate=   2.1kbits/s speed=0.23x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=  107 fps=9.7 q=28.0 size=       1kB time=00:00:02.70 bitrate=   1.9kbits/s speed=0.244x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=  113 fps=9.7 q=28.0 size=       1kB time=00:00:03.00 bitrate=   1.7kbits/s speed=0.258x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
      Last message repeated 5 times
  frame=  119 fps=9.7 q=28.0 size=       1kB time=00:00:03.30 bitrate=   1.5kbits/s speed=0.269x    
  [swscaler @ 0x564d22d76680] deprecated pixel format used, make sure you did set range correctly
  frame=  120 fps=8.6 q=-1.0 Lsize=    1338kB time=00:00:05.85 bitrate=1873.8kbits/s speed=0.419x    
  video:1337kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.115425%
  [libx264 @ 0x564d225e3180] frame I:2     Avg QP:22.50  size: 53106
  [libx264 @ 0x564d225e3180] frame P:40    Avg QP:23.81  size: 17895
  [libx264 @ 0x564d225e3180] frame B:78    Avg QP:26.09  size:  7002
  [libx264 @ 0x564d225e3180] consecutive B-frames:  1.7% 16.7% 55.0% 26.7%
  [libx264 @ 0x564d225e3180] mb I  I16..4:  7.6% 74.5% 17.9%
  [libx264 @ 0x564d225e3180] mb P  I16..4:  2.0% 12.3%  2.5%  P16..4: 43.7% 12.6%  5.6%  0.0%  0.0%    skip:21.3%
  [libx264 @ 0x564d225e3180] mb B  I16..4:  0.8%  3.1%  0.4%  B16..8: 35.0%  2.9%  0.5%  direct: 3.7%  skip:53.5%  L0:35.9% L1:61.7% BI: 2.4%
  [libx264 @ 0x564d225e3180] 8x8 transform intra:72.9% inter:80.7%
  [libx264 @ 0x564d225e3180] coded y,uvDC,uvAC intra: 63.5% 86.3% 57.4% inter: 14.6% 31.4% 3.4%
  [libx264 @ 0x564d225e3180] i16 v,h,dc,p: 27% 24% 10% 38%
  [libx264 @ 0x564d225e3180] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 16% 16%  7% 10% 10%  9%  8%  8%
  [libx264 @ 0x564d225e3180] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 16% 13%  7% 12% 10% 10%  7%  5%
  [libx264 @ 0x564d225e3180] i8c dc,h,v,p: 45% 23% 21% 12%
  [libx264 @ 0x564d225e3180] Weighted P-Frames: Y:52.5% UV:50.0%
  [libx264 @ 0x564d225e3180] ref P L0: 49.9% 20.3% 12.0%  9.1%  8.7%
  [libx264 @ 0x564d225e3180] ref B L0: 74.9% 17.1%  8.0%
  [libx264 @ 0x564d225e3180] ref B L1: 97.6%  2.4%
  [libx264 @ 0x564d225e3180] kb/s:1824.23
  
  ```
  
  Here is some info about the `out.mkv` file:
  
  ```
  Format                                   : Matroska
  Format version                           : Version 4
  File size                                : 850 KiB
  Duration                                 : 6 s 0 ms
  Overall bit rate                         : 1 160 kb/s
  ...
  Format settings, Reference frames        : 4 frames
  Codec ID                                 : V_MPEG4/ISO/AVC
  Duration                                 : 6 s 0 ms
  Bit rate                                 : 1 137 kb/s
  Width                                    : 1 080 pixels
  Height                                   : 720 pixels
  Display aspect ratio                     : 3:2
  Frame rate mode                          : Constant
  Frame rate                               : 20.000 FPS
  Color space                              : YUV
  Chroma subsampling                       : 4:2:0
  Bit depth                                : 8 bits
  Scan type                                : Progressive
  Bits/(Pixel*Frame)                       : 0.073
  
  ```
  
  I've tried different strategies with the `-r` option, but I cannot get my 2 seconds video at 20 fps. Can you see what going on?
  
  Also I would like to keep a `image2pipe` solution instead of a `image2` solution.
  
  **Tags:** ffmpeg, linux
  
  > **Comments:**
  > **username_1**: Share full log.  
  > **username_0**: @username_1 I edited the post with the full ffmpeg log  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2021-10-29. Score: 0
  
  you have to specify both an input and an output framerate, right now you are only setting the input framerate. Try
  
  ```
  find dir/ -iname '*.jpg' | xargs cat | ffmpeg -f image2pipe -r 20 -i - -s 1080x720 -r 20 -pix_fmt yuv420p out.mkv
  
  ```
  
  hope this works
  
  > **Comments:**
  > **username_0**: I still obtain a 6 seconds video with your command  
  
  ---
  
  