ffmpeg recipes

ffmpeg.sh

# -preset veryslow/slow/medium/fast/veryfast
# add -t 60 to produce a 60 second test file before committing to the full reencode 
# for animated video add: -tune animation
# replace or add new metadata with: -metadata title="my description"

# reencode as h264
# lower crf is better quality
ffmpeg -i input.mkv -c:v h264 -crf 18 output.mkv

# reencode as h265
ffmpeg -i input.mkv -c:v h265 -crf 18 output.mkv

# fix the plex odd behavior when reencoding the audio/subtitle
ffmpeg -fflags +genpts -i "$i" -c:v h264 -c:a aac -metadata:s:a:0 language=eng $tempdir/"${filename%.*}".mkv

# Map video + (bitmap subtitle), along with first audio:
ffmpeg -i "$i" -i "$subtitle".srt -map 0:v -map 0:a:0 -map 0:a:1 -map 1:s:0 output.mkv

# replace existing sub with english one, no reencoding 
ffmpeg -i input.mkv -i input.en.srt -map 0:v -map 0:a -map 1 -c:v copy -c:a copy -c:s copy -metadata:s:s:0 language=eng output.mkv 

# extract audio and reencode as mp3 (remove all options other than -i and output, to just extract)
ffmpeg -i input.mkv -vn -ar 44100 -ac 2 -ab 128k -f mp3 output.mp3

# concat simple
# create files.txt 
# win: (for %%i in (*.wmv) do @echo file '%%i') > files.txt
# ps: foreach ($i in Get-ChildItem .\*.wmv) {echo "file '$i'" >> mylist.txt}
# nix: for f in ./*.mp4; do echo "file '$f'" >> files.txt; done
ffmpeg -f concat -safe 0 -i files.txt -c copy output.mp4

# joining two files with conversion
ffmpeg -i in1.mp4 -c copy -bsf h264_mp4toannexb 100.h264
ffmpeg -i in2.mp4 -c copy -bsf h264_mp4toannexb 200.h264
ffmpeg -i "concat:100.h264|200.h264" -i audio_in.mp3 -c copy output.mp4  # use mp4box for this

# Reencoding with NVIDIA, reducing to 1.5M b/s, 720p
# -r 30 will add in a 30fps limit, but that will cause a conflict with vsync
ffmpeg -y -vsync 0 -c:v h264_cuvid -i input.mp4 -vf "scale=-1:720" -b:v 1.5M -c:v h264_nvenc -strict -2 -movflags +faststart output.mp4

-- bash yt downloads:
for x in `ls *webm`
do
echo $x
ffmpeg -i $x -vsync 0 -c:v h264_cuvid -crf 20 -c:v h264_nvenc -c:a ac3 -b:a 384k -ac 2 -c:s copy -max_muxing_queue_size 1024 -movflags +faststart ${x%.*}.mp4
done

# my current set of options on windows, using a RTX 2080, processing bitrate: 3800 kb/sec
# this is a simple re-encode to the latest x264 codec, removing extra subtitles (only 0:2 is copied), all audio is converted to ac3
ffmpeg -y -vsync 0 -map 0 -c:v h264_cuvid -crf 20 -c:v h264_nvenc -c:a ac3 -b:a 384K -ac 2 -map 0:2 -c:s copy -max_muxing_queue_size 1024 -movflags +faststart

## HEVC high quality encoding using GPU - HEVC enabled further compression (reduced file size than H.264)
-c:v hevc_nvenc 
-b:v 6M 
-maxrate 9M 
-bufsize 12M 
-preset slow 
-pix_fmt p010le 
-profile:v main10 
-level 4.1 
-tier high 
-refs 3 
-coder 1 
-rc vbr_hq 
-rc-lookahead 32 
-bf 3 
-b_ref_mode middle 
-b_strategy 1 
-r 24000/1001 
# audio conversion to ac3 if you like
-c:a ac3 -b:a 192K 

# Decrease the darks and bright up the video a bit:
-vf eq=gamma=1.6:contrast=1.4:brightness=0.15:saturation=1.4
# Found a lot of good information and more examples in: https://github.com/chgeuer/mybookmarks/blob/master/ffmpeg%20recipes.md
# HQ Setting from reddit: https://www.reddit.com/r/ffmpeg/comments/k3642t/hq_ffmpeg_encoding_with_gpu_nvenc_part_ii/