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FFmpeg#

Resources#

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Scripts & Snippets#

Scripts#

Map + Metadata Fix#

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for f in *.mkv; do ffmpeg -i "$f" -metadata title="" -map 0:t -map 0:0 -map 0:1 -map 0:2 \
-metadata:s:v title="" -metadata:s:a title="" -metadata:s:s title="" \
-metadata:s:v language=eng -metadata:s:a language=eng -metadata:s:s language=eng \
-c copy "fixed/${f%.mkv}.mkv"; done

re-encode#

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for f in *.mkv; do ffmpeg -i "$f" -metadata title="" \
-preset:v high -level 4.1 -crf 24 -preset slow -tune thing-here \
-c:a libfdk_aac -b:a 256k -c:s copy "encoded/${f%.mkv}.mkv"; done

remux#

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for f in *.mp4; do ffmpeg -i "$f" -i "${f%.mp4}.srt" \
-metadata title="" -metadata:s:v:0 language=eng -metadata:s:s:0 language=eng \
-c:v copy -c:a libfdk_aac -b:a 128k -c:s copy "muxed/${f%.mp4}.mkv"; done

unpack b-frames#

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for f in *.avi; do ffmpeg -i "$f" -codec copy -bsf:v mpeg4_unpack_bframes "unpacked/${f%.avi}.avi"; done

Hardware Encoding#

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for f in *.mkv;do ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 \
-hwaccel_output_format vaapi -i "$f" -vf 'scale_vaapi=format=nv12' \
-c:v hevc_vaapi -rc_mode CQP -global_quality 25 -profile:v main -c:a copy \
-c:s copy "hevc/${f%.mkv}.mkv";done

Snippets#

Common Video Encoding Preset#

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-preset:v high -level 4.1 -crf 24 -preset slow -tune thing-here

This snippet is good for transcoding a video into H.264 with pretty decent device compatibility. You can adjust the crf number down to 18 for a closer-to-lossless output at the cost of filesize. If 24 is too low quality for what you're transcoding, 20 or 22 is usually decent.

tune

You can add a tune with -tune [type] to further customize the output.

Common Audio Encoding Preset#

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-c:a libfdk_aac -b:a 256k

Adjust 256k for the number of audio channels you have.

libfdk_aac is regarded as one of the best audio options available in FFmpeg to output to. libfdk_aac is not part of FFmpeg by default and requires FFmpeg to be compiled a specific way to include non-free software. Compatibility with AAC is fantastic and you can get very good sound quality at lower bitrates than options like MP3.

bitrate/channels

As a rule of thumb, for audible transparency, use 64 kBit/s for each channel (e.g. 128 kBit/s for stereo, 384 kBit/s for 5.1 surround sound).

Map Attachments#

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-map 0:t

This snippet makes sure that all already embedded attachments in a file are copied over. FFmpeg does not do this by default.

Change default track#

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-disposition:[s|a|v]:0 default

This snippet helps you map a specific subtitle, audio, or video channel as the default.

Note

Change 0 to the actual track number for that type.