使用 ffmpeg 将 mp4 转换为 gif 时降低 fps [英] lower fps when using ffmpeg to convert mp4 to gif

问题描述

我正在使用 ffmpeg 将高质量视频转换为 gif，大多数视频都是 60fps 和超过 720p，但是当我使用下面的代码将视频转换为 gif 时，我得到了gif 输出的 fps 低，

I am using ffmpeg to convert high quality videos to gif, most of the videos are 60fps and over 720p, but when I use the code below, to convert the video to gif, I get very low fps for the gif output,

#!/usr/bin/env
palette=/tmp/pallete.png
filter="fps=50,scale=480:-1:flags=lanczos"

ffmpeg -y  -i test.mov -vf $filter,palettegen=stats_mode=diff $palette
ffmpeg -y -i test.mov -i $palette -lavfi "$filter [x]; [x][1:v] paletteuse" test.gif

我注意到的另一个问题是 - 随着宽度的增加，例如 720 而不是 480 我得到的 fps 甚至更低.

another issue I have noted is - as the width increases e.g 720 instead of 480 I get even lower fps.

这里是输出日志示例，输出fps低于指定的50fps

here is output log example, the output fps is lower than the assigned 50fps

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/tmp/201631203815.mp4':
Metadata:
 major_brand     : isom
 minor_version   : 512
 compatible_brands: isomiso2avc1mp41
 encoder         : Lavf56.36.100
Duration: 00:00:05.48, start: 0.016000, bitrate: 1579 kb/s

Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1334x1334, 1576 kb/s, 60.18 fps, 60 tbr, 1000k tbn, 50 tbc (default)
Metadata:
  handler_name    : VideoHandler

Input #1, png_pipe, from '/tmp/pallete.png':
   Duration: N/A, bitrate: N/A
Stream #1:0: Video: png, rgba(pc), 16x16 [SAR 1:1 DAR 1:1], 25 tbr, 25 tbn, 25 tbc

Output #0, gif, to '/tmp/201631203815.gif':
Metadata:
  major_brand     : isom
  minor_version   : 512
  compatible_brands: isomiso2avc1mp41
  encoder         : Lavf56.40.101
Stream #0:0: Video: gif, pal8, 480x480, q=2-31, 200 kb/s, 50 fps, 100 tbn, 50 tbc (default)
Metadata:
  encoder         : Lavc56.60.100 gif
Stream mapping:
   Stream #0:0 (h264) -> fps
   Stream #1:0 (png) -> paletteuse:palette
  paletteuse -> Stream #0:0 (gif)
Press [q] to stop, [?] for help

frame=  275 fps= 32 q=-0.0 Lsize=    2480kB time=00:00:05.50 bitrate=3693.5kbits/s    

我如何确保输出 fps 始终是用户设置的?非常感谢任何关于此的资源.

How do I ensure that the output fps is always whats set by the user? Any resource on this is highly appreciated.

更新

我还注意到使用更高的 fps 例如 filter="fps=90,scale=480:-1:flags=lanczos" 具有减慢 gif 的效果，例如慢动作效果，输出fps仍然低于15fps，

i have also noticed that the use of a higher fps eg filter="fps=90,scale=480:-1:flags=lanczos" has the effect of slowing down the gif,like a slow motion effect, the output fps is still lower around 15fps,

推荐答案

明确设置 fps 值会产生相同的较低 fps 输出结果帧= 346 fps= 24 q=-0.0 Lsize= 6506kB 时间=00:00:06.92比特率=7701.8kbits/s

setting the fps value explicitly gave the same lower fps output results frame= 346 fps= 24 q=-0.0 Lsize= 6506kB time=00:00:06.92 bitrate=7701.8kbits/s

这不是输出fps！这是编码速度.大多数播放器无法正确播放 fps 高于 50 的 GIF.请参阅 demo 展示了这种行为.

This is not the output fps! It's the encoding speed. Most players don't properly play GIFs with a fps higher than 50. See the demo showing this behaviour.

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