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linux:multimedia:movie [2016/03/30 09:08] – niziaklinux:multimedia:movie [2021/02/07 11:21] (current) – niziak
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 +====== Movie ======
  
-==== mpeg2 ====+===== Extract frames ===== 
 +  * Extract keyframes 
 +    * **-hide_banner** we are using this parameter to hide ffmpeg compilation information 
 +    * **-vsync vfr**: This is a parameter that tells the filter to use a variable bitrate video synchronization. If we do not use this parameter ffmpeg will fail to find only the keyframes and shoud extract other frames that can be not processed correctly. 
 +<code bash>ffmpeg -i VIDEO0068.mp4 -vf "select=eq(pict_type\,I)" -vsync vfr thumb%04d.bmp -hide_banner</code> 
 +  * Extract one frame per second 
 +<code bash>ffmpeg -i video.webm -vf fps=1 thumb%04d.jpg -hide_banner</code> 
 +  * Extract one frame per 10 seconds 
 +<code bash>ffmpeg -i video.webm -vf fps=1/10 thumb%04d.jpg -hide_banner</code> 
 +  * Extract with different quality / to bmp 
 +<code bash>ffmpeg -i video.webm -vf fps=1 -quality 90 thumb%04d.jpg -hide_banner</code> 
 +<code bash>ffmpeg -i video.webm -vf fps=1 thumb%04d.bmp -hide_banner</code> 
 +  * Extract only one frame 
 +<code bash>ffmpeg -i video.webm -ss 00:00:07.000 -vframes 1 thumb.jpg</code> 
 + 
 +===== Chroma subsampling ===== 
 +[[https://en.wikipedia.org/wiki/Chroma_subsampling]] 
 +{{ :linux:multimedia:sampling.jpg?200|}} 
 +{{ :linux:multimedia:316-f6-chroma-subsampling-secondary_1.png?200|}} 
 +  * j:a:b - j - horizontal sampling reference (usually 4). **a** number of chroma samples (Cr, Cb) in the first row of **j** pixels. **b** number of changes of chroma samples between firs and second row of **j** pixels. 
 +  * 4:4:4 - (H265, H264) - no chroma subsampling - for every 4 pixels of luma, there are 4 pixels of colour 
 +  * 4:2:2 - 50Mbit - (H264) for every 4 pixels of luma, there are 2 pixels of colour. Keying can produce bad edges. 
 +  * 4:2:0 - 35MBit - (DVD, DV, JPEG, MPEG1, Blueray) - only alternatign lines are sampled for chroma. Chroma vertical resolution is halved. 
 + 
 + 
 +===== Stabilisation ===== 
 + 
 +==== To remove Little shaking in 1-pass ==== 
 + 
 +<code bash>ffmpeg -threads 8 -i $1 -vf deshake -c:a copy -c:v utvideo yuv420p $1-deshake.mkv</code> 
 +NOTE: No multithreading. 
 + 
 +==== To completely process shaky video in 2-pass| ==== 
 + 
 +FFMpeg already contains plugins **vidstabdetect** and **vidstabtransform** [[http://public.hronopik.de/vid.stab/download.php]]. 
 +But latest version (supports multithreading) can be downloaded as statically linked binary from: [[https://www.johnvansickle.com/ffmpeg/]] 
 + 
 +<code bash> 
 +ffmpeg -i $1 -vf vidstabdetect=shakiness=10:accuracy=15:result="tracefile.trf":show=1 -c:a copy -c:v utvideo ${PIX_FMT} ${OFILE}-vidstab1.mkv 
 +ffmpeg -i $1 -vf vidstabtransform=input="tracefile.trf" -c:a copy -c:v utvideo ${PIX_FMT} ${OFILE}-vidstab2.mkv 
 +</code> 
 +NOTE: output from pass1 is also written as video to see motion vectors. 
 + 
 + 
 + 
 + 
 + 
 +===== Lossless ===== 
 + 
 +Use UT Video codec as better alternative to HUFYUV: [[https://en.wikipedia.org/wiki/Ut_Video_Codec_Suite]] 
 +  * Download for Windows: https://www.videohelp.com/software/Ut-Video-Codec-Suite 
 +  * Supported by ffmpeg 
 +<code bash>ffmpeg -i $1 -vf deshake -c:a copy -c:v utvideo -pix_fmt yuv422p $1-deshake.mkv</code> 
 + 
 +Comparison of file size: 
 +^ pixfmt ^ huffyuv ^ utvideo ^ 
 +| 444p   |         | 4104M   | 
 +| 422p   | 4077M   | 3204M   |  
 +| 420p   |         | 2556M   | 
 + 
 +The same video encoded using **utvideo** @422p is 78% of **huffyuv**. 
 +===== MPEG2 =====
 Highest quality (qscale 4-5 is far enough) Highest quality (qscale 4-5 is far enough)
 <code>-c:v mpeg2video -qscale:v 2</code> <code>-c:v mpeg2video -qscale:v 2</code>
 +==== DVD ====
 +DVD's VOBS can be simply concatenated to one big file:
 +<code bash>cat ./VIDEO_TS/*.VOB | ffmpeg -i - <out_name>.<out_format></code>
  
-==== H.264 params ====+<code bash> 
 +#!/bin/bash -eu 
 + 
 +VOBS="" 
 +while read VOB; do 
 +    echo ${VOB} 
 +    if [ -n "${VOBS}" ]; then 
 + VOBS="${VOBS}|" 
 +    fi 
 +    VOBS="${VOBS}${VOB}" 
 +done < <(ls -1 *.VOB) 
 + 
 +ffmpeg -i "concat:${VOBS}" -map 0:0 -map 0:1 -map 0:2 -c copy out.ts 
 +</code> 
 +More: [[https://newspaint.wordpress.com/2016/07/27/ripping-a-video-from-dvd-using-ffmpeg/]] 
 + 
 + 
 +===== H.264 params =====
 CRF (Constant Rate Factor), 0..51  (0-lossless) CRF (Constant Rate Factor), 0..51  (0-lossless)
   * 17..23 very good, no blocking efect during fast movement   * 17..23 very good, no blocking efect during fast movement
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 <code>-c:v libx264 -b:v 1024k</code> <code>-c:v libx264 -b:v 1024k</code>
  
-==== FFMpeg params ====+===== FFMpeg params =====
 2.5Mbps bitrate with tolerance 300k 2.5Mbps bitrate with tolerance 300k
 <code>-b 2500k -bt 300k</code> <code>-b 2500k -bt 300k</code>
  
-=== Resize ===+==== Resize ====
 to half of size (using video filter [[https://ffmpeg.org/ffmpeg-filters.html#scale]] to half of size (using video filter [[https://ffmpeg.org/ffmpeg-filters.html#scale]]
 <code>-vf scale=w=iw/2:h=ih/2</code> <code>-vf scale=w=iw/2:h=ih/2</code>
  
-=== Audio recompress ===+==== Audio recompress ====
 1 channel audio (mono), audio quality 7 [[https://trac.ffmpeg.org/wiki/Encode/MP3]] 1 channel audio (mono), audio quality 7 [[https://trac.ffmpeg.org/wiki/Encode/MP3]]
 <code>-ac 1 -c:a libmp3lame -q:a 7</code> <code>-ac 1 -c:a libmp3lame -q:a 7</code>
  
-==== Examples ====+===== Examples =====
  
-=== Change container ===+==== Change container ====
 <code>ffmpeg -i input.ts -vcodec copy -sameq -acodec copy -f matroska output.ts</code> <code>ffmpeg -i input.ts -vcodec copy -sameq -acodec copy -f matroska output.ts</code>
  
-=== Recompress ===+==== Copy video and compress audio ==== 
 +Create mono mp3 audio stream: 
 +<code bash>ffmpeg -i input_file.avi -c:v copy -ac 1 -c:a libmp3lame -q:a 7 output.avi</code> 
 + 
 +==== Remove audio ==== 
 +<code bash>ffmpeg -i example.mkv -c copy -an example-nosound.mkv</code> 
 + 
 +==== Recompress ====
 <code> <code>
 ffmpeg -i input.mp4 -b 1000000 output.mp4 ffmpeg -i input.mp4 -b 1000000 output.mp4
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 <code>cpulimit -z -e ffmpeg -l 150</code> <code>cpulimit -z -e ffmpeg -l 150</code>
  
-=== Cut ===+==== Cut ====
 Cut input from 11:20 to 1:45:50: Cut input from 11:20 to 1:45:50:
  
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 Copy chosen streams and resize to 50%, recompress video stream: Copy chosen streams and resize to 50%, recompress video stream:
-<code>ffmpeg -i test.ts -to 5:47 -map 0:0 -map0:1 -map 0:4 -c copy -c:v libx264 -crf 25 -vf scale=w=iw/2:h=ih/2 cut.mkv</code>+<code bash>ffmpeg -i test.ts -to 5:47 -map 0:0 -map0:1 -map 0:4 -c copy -c:v libx264 -crf 25 -vf scale=w=iw/2:h=ih/2 cut.mkv</code>
  
 +==== Deinterlace ====
  
 +<code bash> ffmpeg -i test.ts -vf yadif -vcodec ... -acodec ... test.mp4</code>
  
 vidia vidia
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 https://www.maketecheasier.com/convert-video-to-mp4-handbrake-linux/ https://www.maketecheasier.com/convert-video-to-mp4-handbrake-linux/
  
 +===== Issues =====
 + * **deprecated pixel format used, make sure you did set range correctly**
 +   * when using **yuv420p** pixel format