Answers.Body: <p>Use</p>
  
  <pre><code>ffmpeg
   -ss 00:00:19.7500417 -i "S:\vids\main.mp4"
   -ss 00:00:39.5000834 -i "S:\vids\main.mp4"
   -ss 00:00:59.2501251 -i "S:\vids\main.mp4"
   -filter_complex
   "[0]trim=end_frame=1,scale=-1:480,setpts=N[a];
    [1]trim=end_frame=1,scale=-1:480,setpts=N[b];
    [2]trim=end_frame=1,scale=-1:480,setpts=N[c];
    [a][b][c]vstack=3"
  "thumbnails\main.jpg"
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-04T04:18:12.533Z
Answers.Text: Thanks for the answer, but this results in an error "Too many inputs specified for the "vstack" filter". I've included the full output in my question.
Answers.UserDisplayName: Sam
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-04T04:29:04.137Z
Answers.Text: Command edited.
Answers.UserDisplayName: Gyan
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-04T05:11:17.073Z
Answers.Text: Your solution works great, but takes as much RAM as the video size, which is excessive when the video size itself is 15G or more. Since I only need specific frames, is there any way I can avoid loading the entire video into memory? Perhaps by only using keyframes (or other easy to read approximations)?
Answers.UserDisplayName: Sam
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-04T07:05:57.360Z
Answers.Text: It won't load the entire video into memory. Add -benchmark to your cmd and share full log.
Answers.UserDisplayName: Gyan
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-12T02:19:06.160Z
Answers.Text: Sorry for the late response - loading the entire video seems to be an issue related to working with remote files. That issue is resolved.
Answers.UserDisplayName: Sam
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-12T02:20:07.553Z
Answers.Text: There is however a common issue with your solution that ffmpeg segfaults in some cases like `Stream #0:0: Video: mjpeg, yuvj420p(pc), 480x13550 [SAR 271:272 DAR 3:85], q=2-31, 200 kb/s, 15 fps, 15 tbn, 15 tbc (default)`. I'll create an issue in the bug tracker.
Answers.UserDisplayName: Sam
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-03T08:39:37.620Z
Answers.LastActivityDate: 2019-10-04T04:28:50.517Z
Answers.LastEditDate: 2019-10-04T04:28:50.517Z
Answers.UserDisplayName: Gyan
Body: <p>I have a server software that generates video thumbnails using ffmpeg in two steps like this:</p>
  
  <p><strong>Step 1</strong></p>
  
  <pre><code>-ss 00:00:19.7500417 -i "S:\vids\main.mp4"
  -ss 00:00:39.5000834 -i "S:\vids\main.mp4"
  -ss 00:00:59.2501251 -i "S:\vids\main.mp4"
  -y -threads 1 -frames:v 1 -vf "scale=-1:480" -map 0:v:0 "temp\temp0.jpg"
  -y -threads 1 -frames:v 1 -vf "scale=-1:480" -map 1:v:0 "temp\temp1.jpg"
  -y -threads 1 -frames:v 1 -vf "scale=-1:480" -map 2:v:0 "temp\temp2.jpg"
  </code></pre>
  
  <p><strong>Step 2</strong></p>
  
  <pre><code>-i "temp\temp%d.jpg" -y -filter_complex tile=1x3 "thumbnails\main.jpg"
  </code></pre>
  
  <p>This works fine when only a few thumbnails are needed, but when 50-100 thumbnails must be written to disk and then tiled separately, overall performance is very slow.</p>
  
  <p>Is there some way I can combine these two commands into a single step?</p>
  
  <p><strong>UPDATE</strong>: @gyan's code results in:</p>
  
  <pre><code>PS C:\Users\Sam\Desktop&gt; .\ffmpeg.exe  -ss 00:00:19.7500417 -i "S:\vids\main.mp4" -ss 00:00:39.5000834 -i "S:\vids\main.mp4" -ss 00:00:59.2501251 -i "S:\vids\main.mp4" -filter_complex "[0]trim=end_frame=1,scale=-1:480,setpts=N[a]; [1]trim=end_frame=1,scale=-1:480,setpts=N[b]; [2]trim=end_frame=1,scale=-1:480,setpts=N[c]; [a][b][c]vstack" "thumbnails\main.jpg"
  ffmpeg version 4.2 Copyright (c) 2000-2019 the FFmpeg developers
    built with gcc 9.1.1 (GCC) 20190807
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
    libavutil      56. 31.100 / 56. 31.100
    libavcodec     58. 54.100 / 58. 54.100
    libavformat    58. 29.100 / 58. 29.100
    libavdevice    58.  8.100 / 58.  8.100
    libavfilter     7. 57.100 /  7. 57.100
    libswscale      5.  5.100 /  5.  5.100
    libswresample   3.  5.100 /  3.  5.100
    libpostproc    55.  5.100 / 55.  5.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'S:\vids\main.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.83.100
    Duration: 00:01:19.95, start: 0.000000, bitrate: 529 kb/s
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 406x720 [SAR 1:1 DAR 203:360], 424 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
      Metadata:
        handler_name    : VideoHandler
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 96 kb/s (default)
      Metadata:
        handler_name    : SoundHandler
  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'S:\vids\main.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.83.100
    Duration: 00:01:19.95, start: 0.000000, bitrate: 529 kb/s
      Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 406x720 [SAR 1:1 DAR 203:360], 424 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
      Metadata:
        handler_name    : VideoHandler
      Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 96 kb/s (default)
      Metadata:
        handler_name    : SoundHandler
  Input #2, mov,mp4,m4a,3gp,3g2,mj2, from 'S:\vids\main.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.83.100
    Duration: 00:01:19.95, start: 0.000000, bitrate: 529 kb/s
      Stream #2:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 406x720 [SAR 1:1 DAR 203:360], 424 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
      Metadata:
        handler_name    : VideoHandler
      Stream #2:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 96 kb/s (default)
      Metadata:
        handler_name    : SoundHandler
  [AVFilterGraph @ 000001dcaf4fef40] Too many inputs specified for the "vstack" filter.
  Error initializing complex filters.
  Invalid argument
  </code></pre>
  
Tags: <ffmpeg><thumbnails>
Title: Capturing and tiling video thumbnails in a single step
UserDisplayName: Sam
ThreadText: # Capturing and tiling video thumbnails in a single step
  
  (Asked by: username_0 on 2019-10-03)
  
  I have a server software that generates video thumbnails using ffmpeg in two steps like this:
  
  **Step 1**
  
  ```
  -ss 00:00:19.7500417 -i "S:\vids\main.mp4"
  -ss 00:00:39.5000834 -i "S:\vids\main.mp4"
  -ss 00:00:59.2501251 -i "S:\vids\main.mp4"
  -y -threads 1 -frames:v 1 -vf "scale=-1:480" -map 0:v:0 "temp\temp0.jpg"
  -y -threads 1 -frames:v 1 -vf "scale=-1:480" -map 1:v:0 "temp\temp1.jpg"
  -y -threads 1 -frames:v 1 -vf "scale=-1:480" -map 2:v:0 "temp\temp2.jpg"
  
  ```
  
  **Step 2**
  
  ```
  -i "temp\temp%d.jpg" -y -filter_complex tile=1x3 "thumbnails\main.jpg"
  
  ```
  
  This works fine when only a few thumbnails are needed, but when 50-100 thumbnails must be written to disk and then tiled separately, overall performance is very slow.
  
  Is there some way I can combine these two commands into a single step?
  
  **UPDATE**: @username_1's code results in:
  
  ```
  PS C:\Users\Sam\Desktop> .\ffmpeg.exe  -ss 00:00:19.7500417 -i "S:\vids\main.mp4" -ss 00:00:39.5000834 -i "S:\vids\main.mp4" -ss 00:00:59.2501251 -i "S:\vids\main.mp4" -filter_complex "[0]trim=end_frame=1,scale=-1:480,setpts=N[a]; [1]trim=end_frame=1,scale=-1:480,setpts=N[b]; [2]trim=end_frame=1,scale=-1:480,setpts=N[c]; [a][b][c]vstack" "thumbnails\main.jpg"
  ffmpeg version 4.2 Copyright (c) 2000-2019 the FFmpeg developers
    built with gcc 9.1.1 (GCC) 20190807
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
    libavutil      56. 31.100 / 56. 31.100
    libavcodec     58. 54.100 / 58. 54.100
    libavformat    58. 29.100 / 58. 29.100
    libavdevice    58.  8.100 / 58.  8.100
    libavfilter     7. 57.100 /  7. 57.100
    libswscale      5.  5.100 /  5.  5.100
    libswresample   3.  5.100 /  3.  5.100
    libpostproc    55.  5.100 / 55.  5.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'S:\vids\main.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.83.100
    Duration: 00:01:19.95, start: 0.000000, bitrate: 529 kb/s
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 406x720 [SAR 1:1 DAR 203:360], 424 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
      Metadata:
        handler_name    : VideoHandler
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 96 kb/s (default)
      Metadata:
        handler_name    : SoundHandler
  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'S:\vids\main.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.83.100
    Duration: 00:01:19.95, start: 0.000000, bitrate: 529 kb/s
      Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 406x720 [SAR 1:1 DAR 203:360], 424 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
      Metadata:
        handler_name    : VideoHandler
      Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 96 kb/s (default)
      Metadata:
        handler_name    : SoundHandler
  Input #2, mov,mp4,m4a,3gp,3g2,mj2, from 'S:\vids\main.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      encoder         : Lavf57.83.100
    Duration: 00:01:19.95, start: 0.000000, bitrate: 529 kb/s
      Stream #2:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 406x720 [SAR 1:1 DAR 203:360], 424 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
      Metadata:
        handler_name    : VideoHandler
      Stream #2:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 96 kb/s (default)
      Metadata:
        handler_name    : SoundHandler
  [AVFilterGraph @ 000001dcaf4fef40] Too many inputs specified for the "vstack" filter.
  Error initializing complex filters.
  Invalid argument
  
  ```
  
  **Tags:** ffmpeg, thumbnails
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2019-10-03. Score: 0 | Accepted answer
  
  Use
  
  ```
  ffmpeg
   -ss 00:00:19.7500417 -i "S:\vids\main.mp4"
   -ss 00:00:39.5000834 -i "S:\vids\main.mp4"
   -ss 00:00:59.2501251 -i "S:\vids\main.mp4"
   -filter_complex
   "[0]trim=end_frame=1,scale=-1:480,setpts=N[a];
    [1]trim=end_frame=1,scale=-1:480,setpts=N[b];
    [2]trim=end_frame=1,scale=-1:480,setpts=N[c];
    [a][b][c]vstack=3"
  "thumbnails\main.jpg"
  
  ```
  
  > **Comments:**
  > **username_0**: Thanks for the answer, but this results in an error "Too many inputs specified for the "vstack" filter". I've included the full output in my question.  
  > **username_1**: Command edited.  
  > **username_0**: Your solution works great, but takes as much RAM as the video size, which is excessive when the video size itself is 15G or more. Since I only need specific frames, is there any way I can avoid loading the entire video into memory? Perhaps by only using keyframes (or other easy to read approximations)?  
  > **username_1**: It won't load the entire video into memory. Add -benchmark to your cmd and share full log.  
  > **username_0**: Sorry for the late response - loading the entire video seems to be an issue related to working with remote files. That issue is resolved.  
  > **username_0**: There is however a common issue with your solution that ffmpeg segfaults in some cases like `Stream #0:0: Video: mjpeg, yuvj420p(pc), 480x13550 [SAR 271:272 DAR 3:85], q=2-31, 200 kb/s, 15 fps, 15 tbn, 15 tbc (default)`. I'll create an issue in the bug tracker.  
  
  ---
  
  