Sur d’autres sites (6289)

• avfilter/vpp_amf : add option reset_sar

  10 février, par Gyan Doshi

  avfilter/vpp_amf : add option reset_sar
  4b77a0a681 added a new consumer of ff_scale_adjust_dimensions
  
  which was recently modified to allow for square pixel output.
  This commit extends the new option to vpp_amf, and unbreaks the building
  
  of vf_amf_common.c
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/vf_amf_common.c
  • [DH] libavfilter/vf_amf_common.h
  • [DH] libavfilter/vf_vpp_amf.c

• FFmpeg h264_v4l2m2m encoder changing aspect ratio from 16:9 to 1:1 with black bars

  8 janvier, par LycoReco2007

  When switching from libx264 to h264_v4l2m2m encoder in FFmpeg for YouTube streaming, the output video's aspect ratio changes from 16:9 to 1:1 with black bars on the sides, despite keeping the same resolution settings.

  


  Original working command (with libx264) :

  


  ffmpeg -f v4l2 \
    -input_format yuyv422 \
    -video_size 1280x720 \
    -framerate 30 \
    -i /dev/video0 \
    -f lavfi \
    -i anullsrc=r=44100:cl=stereo \
    -c:v libx264 \
    -preset ultrafast \
    -tune zerolatency \
    -b:v 2500k \
    -c:a aac \
    -b:a 128k \
    -ar 44100 \
    -f flv rtmp://a.rtmp.youtube.com/live2/[STREAM-KEY]


  


  When I replaced libx264 with h264_v4lm2m, it always produce a square resolution, and it automatically adds black bars to the top and the bottom of the sides of the camera. I currently using a Rasberry Pi 4 model B, with a webcam that I believe supports the 16:9 ratio (I've verified using v4l2-ctl --list-formats-ext -d /dev/video0 command)

  


  I've tried the follows :

  


  

  • Adding -aspect 16:9 parameter in the ffmpeg command

  


  • Adding video filters such as -vf "scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:(ow-iw)/2:(oh-ih)/2,setsar=1"
None of these give me the correct aspect ratio.

  


  


  How can I make the h264_v4l2m2m encoder maintain the original 16:9 aspect ratio without adding black bars ? Is this a known limitation of the encoder, or am I missing some required parameters ?

  


• FFprobe reading incorrect resolution value despite players rendering it correctly

  28 octobre 2024, par Boehmi

  I'm creating a video from a stream with the help of FFMPEG and I also use FFPROBE to gather information for use on a status page like resolution, codecs et cetera.

  



  When FFProbe parses my video for information, I get a resolution value of 544x576 (almost a square !), but an aspect ratio of 16:9.

  



  These values are consistent on both the input stream and my saved video.

  



  When I watch the video in the standard HTML5 Player, VLC or FFPLAY however, I get a video with the proportions of 16:9 and a resolution (measured using an image editing program) of 1024x576 that does look native and not stretched in any way.

  



  Even if I re-encode the video using slightly different codecs, this incorrect resolution value persists, even though every player I use displays it correctly.

  



  This is slightly inconvenient because I am relying on getting the correct resolution value from the video for further processing.

  



  I'm also using a recent FFMPEG+FFPROBE version that was compiled on the 15th of July.

  



  Is this a bug within FFMPEG or is there anything I'm doing wrong ?

  



  Used command lines :

  



  FFMPEG :

  



  ffmpeg -i source -loglevel debug -vcodec copy -acodec copy -bsf:a aac_adtstoasc -movflags +faststart -t 360 -y video.mp4


  



  FFPROBE (I parse the output of this directly and save the values) :

  



  ffprobe -i source -show_format -show_streams 


  



  FFProbe output :

  



  width=544
height=576
coded_width=544
coded_height=576
has_b_frames=2
sample_aspect_ratio=32:17
display_aspect_ratio=16:9


  



  I can see that the sample aspect ratio is different from the display aspect ratio, but how come the video looks proper in 16:9 when it's supposedly encoded at a near square resolution ?