Ffmpeg change aspect ratio do not succeeded

Question

I'm trying to change the aspect ratio of video, cause it's being showed in a wrong way (it sould be 16:9 but shows 3:4). I've tried a lot of things, and none worked. E.g. I've tried to set SAR, but it changes DAR, so the aspect ratio stays the same. Here's an example:

ffmpeg -y -i rtmp://localhost/in/air-hdmi -vf "setsar=sar=16/9" -f flv rtmp://localhost/in/ngoraltestffmpeg 


    ffmpeg version N-80388-gfd1d84b Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  configuration: --prefix=/home/anastasia/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/home/anastasia/ffmpeg_build/include --extra-ldflags=-L/home/anastasia/ffmpeg_build/lib --bindir=/home/anastasia/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree
  libavutil      55. 24.100 / 55. 24.100
  libavcodec     57. 46.100 / 57. 46.100
  libavformat    57. 38.101 / 57. 38.101
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 46.101 /  6. 46.101
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100

[flv @ 0x38143c0] audio stream discovered after head already parsed
[aac @ 0x3818f20] element type mismatch 1 != 0
[flv @ 0x38143c0] video stream discovered after head already parsed
Input #0, flv, from 'rtmp://localhost/in/air-hdmi':
  Metadata:
    Server          : NGINX RTMP (github.com/arut/nginx-rtmp-module)
    displayWidth    : 720
    displayHeight   : 576
    fps             : 0
    profile         : 
    level           : 
  Duration: 00:00:00.00, start: 181748.084000, bitrate: N/A
    Stream #0:0: Audio: aac (HE-AAC), 44100 Hz, stereo, fltp
    Stream #0:1: Video: h264 (High), yuv420p, 720x576, 25 fps, 25 tbr, 1k tbn, 50 tbc
[flv @ 0x39bf5a0] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
    Last message repeated 1 times
Output #0, flv, to 'rtmp://localhost/in/ngoraltest':
  Metadata:
    Server          : NGINX RTMP (github.com/arut/nginx-rtmp-module)
    displayWidth    : 720
    displayHeight   : 576
    fps             : 0
    profile         : 
    level           : 
    encoder         : Lavf57.38.101
    Stream #0:0: Video: flv1 (flv) ([2][0][0][0] / 0x0002), yuv420p, 720x576 [SAR 16:9 DAR 20:9], q=2-31, 200 kb/s, 25 fps, 1k tbn, 25 tbc
    Metadata:
      encoder         : Lavc57.46.100 flv
    Side data:
      cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: mp3 (libmp3lame) ([2][0][0][0] / 0x0002), 44100 Hz, stereo, fltp
    Metadata:
      encoder         : Lavc57.46.100 libmp3lame
Stream mapping:
  Stream #0:1 -> #0:0 (h264 (native) -> flv1 (flv))
  Stream #0:0 -> #0:1 (aac (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
[aac @ 0x3a37000] element type mismatch 1 != 0
    Last message repeated 7 times
[flv @ 0x39bf5a0] Failed to update header with correct duration.ate= 942.7kbits/s speed=2.37x    
[flv @ 0x39bf5a0] Failed to update header with correct filesize.
frame=  112 fps= 48 q=31.0 Lsize=     633kB time=00:00:05.18 bitrate= 999.9kbits/s speed=2.23x    
video:546kB audio:82kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.846813%
Exiting normally, received signal 2.

Using setdar=16/9 do not succeeds: it changes PAR, so the result is the same:

Input #0, flv, from 'rtmp://localhost/in/air-hdmi':
  Metadata:
    Server          : NGINX RTMP (github.com/arut/nginx-rtmp-module)
    displayWidth    : 720
    displayHeight   : 576
    fps             : 0
    profile         : 
    level           : 
  Duration: 00:00:00.00, start: 287464.746000, bitrate: N/A
    Stream #0:0: Audio: aac (HE-AAC), 44100 Hz, stereo, fltp
    Stream #0:1: Video: h264 (High), yuv420p, 720x576, 25 fps, 25 tbr, 1k tbn, 50 tbc
[flv @ 0x3a5ea20] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
    Last message repeated 1 times
Output #0, flv, to 'rtmp://localhost/in/ngoraltest':
  Metadata:
    Server          : NGINX RTMP (github.com/arut/nginx-rtmp-module)
    displayWidth    : 720
    displayHeight   : 576
    fps             : 0
    profile         : 
    level           : 
    encoder         : Lavf57.38.101
    Stream #0:0: Video: flv1 (flv) ([2][0][0][0] / 0x0002), yuv420p, 720x576 [SAR 64:45 DAR 16:9], q=2-31, 200 kb/s, 25 fps, 1k tbn, 25 tbc
    Metadata:
      encoder         : Lavc57.46.100 flv
    Side data:
      cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: mp3 (libmp3lame) ([2][0][0][0] / 0x0002), 44100 Hz, stereo, fltp
    Metadata:
      encoder         : Lavc57.46.100 libmp3lame
Stream mapping:
  Stream #0:1 -> #0:0 (h264 (native) -> flv1 (flv))
  Stream #0:0 -> #0:1 (aac (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help

(When use setsar, the params are 720x576 [SAR 16:9 DAR 20:9], when setdar -- 720x576 [SAR 64:45 DAR 16:9])

I've also tried to apply scale=720:-1 and -aspect 16:9 and all left the same.

BUT! Wnen I write ffplay -vf setsar=16/9 rtmp://localhost/in/ngoraltest it shows perfectly what I need. What could be thae problem and hoe to solve it?

P.S. I'm little bit confused that there's no onformation about SAR and DAR of input signal, but I can do totally nothing with it.

Gyan Gyan · Accepted Answer · 2016-11-21T16:43:28

You need to use

ffmpeg -y -i rtmp://localhost/in/air-hdmi -vf "setdar=16/9" -f flv rtmp://localhost/in/ngoraltestffmpeg

setsar is the aspect ratio of a sample i.e. one pixel. setdar is for the video. Of course, what setdar does is change the SAR, taking into account the dimensions of the video, so that the display ratio is obtained. DAR = Width x SAR / height

Ffmpeg change aspect ratio do not succeeded

3 Answers