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• Revision 2b8dc065d1 : google style guide include guards Change-Id : I2c252f3ddcc99e96c1f5d3dab8bcb25a2

  30 novembre 2012, par Jim Bankoski

  Changed Paths : Modify /vp9/common/arm/vp9_bilinearfilter_arm.h Modify /vp9/common/arm/vp9_idct_arm.h Modify /vp9/common/arm/vp9_loopfilter_arm.h Modify /vp9/common/arm/vp9_recon_arm.h Modify /vp9/common/arm/vp9_subpixel_arm.h Modify /vp9/common/vp9_alloccommon.h (...)

• FFmpeg : What re-encoding settings can be used to achieve results similar to Google Drive's video processing ?

  4 août 2023, par Mycroft_47

  Context :

  


  I have a large collection of videos recorded by my phone's camera, which is taking up a significant amount of space. Recently, I noticed that when I uploaded a video to Google Drive and then downloaded it again using IDM (by clicking on the pop-up that IDM displays when it detects something that can be downloaded here's what i mean), the downloaded video retained the same visual quality but occupied much less space. Upon further research, I discovered that Google re-encodes uploaded videos using H.264 video encoding, and I believe I can achieve similar compression using FFmpeg.

  


  Problem :

  


  Despite experimenting with various FFmpeg commands, I haven't been able to replicate Google Drive's compression. Every attempt using -codec:v libx264 option alone resulted in videos larger than the original files.

  


  While adjusting the -crf parameter to a higher value and opting for a faster -preset option did yield smaller file sizes, it unfortunately came at the cost of a noticeable degradation in visual quality and the appearance of some visible artifacts in the video.

  


  Google Drive's processing, on the other hand, strikes a commendable balance, achieving a satisfactory file size without compromising visual clarity, (I should note that upon zooming in on this video, I observed some minor blurring, but it was acceptable to me).

  


  Note :

  


  I'm aware that using the H.265 video encoder instead of H.264 may give better results. However, to ensure fairness and avoid any potential bias, I think the optimal approach is first to find the best command using the H.264 video encoder. Once identified, I can then replace -codec:v libx264 with -codec:v libx265. This approach will ensure that the chosen command is really the best that FFMPEG can achieve, and that it is not solely influenced by the superior performance of H.265 when used from the outset.

  


  Here's the FFMPEG command I am currently using :

  


  ffmpeg -hide_banner -loglevel verbose ^
    -i input.mp4 ^
    -codec:v libx264 ^
    -crf 36 -preset ultrafast ^
    -codec:a libopus -b:a 112k ^
    -movflags use_metadata_tags+faststart -map_metadata 0 ^
    output.mp4


  


  





  


  


  


  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  Video file	Size (bytes)	Bit rate (bps)	Encoder	FFPROB - JSON
  Original (named 'raw 1.mp4')	31,666,777	10,314,710	!!!	link
  Without crf	36,251,852	11,805,216	Lavf60.3.100	link
  With crf	10,179,113	3,314,772	Lavf60.3.100	link
  Gdrive	6,726,189	2,190,342	Google	link

  


  


  Those files can be found here.

  


  Update :

  


  I continued my experiments with the video "raw_1.mp4" and found some interesting results that resemble those shown in this blog post, (I recommend consulting this answer).

  


  In the following figure, I observed that using the -preset set to veryfast provided the most advantageous results, striking the optimal balance between compression ratio and compression time, (Note that a negative percentage in the compression variable indicates an increase in file size after processing) :


  


  In this figure, I used the H.264 encoder and compared the compression ratio of different outputted files resulting from seven different values of the -crf parameter (CRF values used : 25, 27, 29, 31, 33, 35, 37),


  


  For this figure, I've switched the encoder to H.265 while maintaining the same CRF values used in the previous figure :


  


  Based on these results, the -preset veryfast and a -crf value of 31 are my current preferred settings for FFmpeg, until they are proven to be suboptimal choices.
As a result, the FFmpeg command I'll use is as follows :

  


  ffmpeg -hide_banner -loglevel verbose ^
    -i input.mp4 ^
    -codec:v libx264 ^
    -crf 31 -preset veryfast ^
    -codec:a libopus -b:a 112k ^
    -movflags use_metadata_tags+faststart -map_metadata 0 ^
    output.mp4


  


  Note that these choices are based solely on the compression results obtained so far, and they do not take into account the visual quality of the outputted files.

  


• Google Lato Font Display discrepancies between platforms/software [closed]

  5 juin 2024, par CRAIG

  Using Google's Lato font with 400 weight, is giving me some inconsistent results between Photoshop/Web on MacOS and Linux Imagemagick & Linux ffmpeg.

  


  I have printed out some text on my linux server using the font using both imagemagick (v6.9.10-68) and ffmpeg's (v6.0) drawtext feature and in both cases, I get some extra space between the T and the e. (Image below)

  


  At first I was only testing ffmpeg and thought it was related to drawtext, but now that imagemagick is doing the same, I am thinking it may be somehow related to how the server is managing the font ?

  


  I did download the exact same font to test on my Mac and installed it, but I still get the original photoshop results I was getting before. So I don't think it is inherently the font unless I missed a step. I did completely uninstall the font and then install the downloaded one to be sure.

  


  However, the same word, font, font-size combo used in Photoshop and on the web does not produce the same space between the T and the e.

  


  Here is an image I put together showing the results :

  


  

  


  For reference, here is the imagemagick command :

  


  convert -size 900x900 xc:black -font /fonts/Lato:400.ttf -pointsize 261.6 -fill white -gravity center -annotate +0+0 'Text' testoutput.png

  


  And the ffmpeg command :

  


  /usr/local/bin/ffmpeg -f  lavfi  -i  color=c=black@0.0:s=953x953:r=30:d=5,format=rgba  -filter_complex  "drawtext=expansion=none:enable='between(t,0,5)':fontfile='/fonts/Lato\:400.ttf':fontcolor=0xffffffff:fontsize=294:text='Text':x=(w-text_w)/2+0:y=476.5-(max_glyph_a)+(294/2.8)"  -copyts  -threads  1  -c:v  png  -pix_fmt  rgba  -movflags  faststart  -r  30  -t  8  -y  testoutput.mov