#!/bin/sh
##
## Nautilus
## SCRIPT: 05_1mp4File_CROP-PERCENTS_ffmpeg-filter-crop_copyAudio_toMP4.sh
##
## PURPOSE: Crop a user-specified area from a '.mp4' movie file using an
##          'ffmpeg' video-filter specification in pixels --- like
##                  -filter:v "crop=out_w:out_h:x:y"
##          --- and make the output movie file an MP4 container
##          and copy the audio format.
##
##          The user is prompted for margin-percents --- top, right,
##          bottom, left. The pixels for out_w, out_h, x, and y
##          are calculated by getting the width and height
##          in pixels of the input video (using the
##          'mediainfo' command) and applying the percents.
##
## METHOD:  Uses 'zenity --entry' to prompt for the percent parameters.
##
##          Uses 'ffmpeg' with '-filter:v' and '-c:a copy' parms.
##
##          Shows the new, cropped movie file in a movie player.
##
## NOTE on TESTING:
##          This script was developed and testing using ffmpeg version 
##          3.4.6, released circa 2019.
##
## HOW TO USE: In Gnome-Nautilus or MATE-Caja, select an mp4 movie file.
##             Then right-click and choose this script to run (name above).
##
###############################################################################
## Started: 2023dec11 Based on FE Nautilus Script
##                    04B_1movieFile_CROP-W-H-X-Y_ffmpeg-filter-crop_toMP4-H264-AAC.sh
##                    and
##                    tested using
##                    ffmpeg version 3.4.6-0ubuntu0.18.04.1
##                    Used 'mediainfo' to get the width&height of the input video.
## Changed: 2024jan17 Add a zenity-entry prompt to allow the user to check the
##                    4 crop parms calculated from the 4 user-specified percentages.
## Changed: 2024mar18 Improved the use of 'mediainfo' to get width&height.
##                    Also, in comments, provided 'ffprobe' & 'ffmpeg' examples
##                    of getting the width&height of the input video.
###############################################################################

## FOR TESTING: (display the executed statements)
#  set -x

#########################################################
## Check if the ffmpeg executable exists.
#########################################################

EXE_FFMPEG="/usr/bin/ffmpeg"

if test ! -f "$EXE_FFMPEG"
then
   zenity --info --title "Executable NOT FOUND." \
   --no-wrap \
   --text  "\
The ffmpeg executable
   $EXE_FFMPEG
was not found. Exiting.

If the executable is in another location,
you can edit this script to change the filename.
OR, install the 'ffmpeg' package."
   exit
fi


#########################################################
## Check if the mediainfo executable exists.
#########################################################

EXE_MEDIAINFO="/usr/bin/mediainfo"

if test ! -f "$EXE_MEDIAINFO"
then
   zenity --info --title "Executable NOT FOUND." \
   --no-wrap \
   --text  "\
The mediainfo executable
   $EXE_MEDIAINFO
was not found. Exiting.

If the executable is in another location,
you can edit this script to change the filename.
OR, install the 'mediainfo' package."
   exit
fi


##############################################
## Get the filename of the selected file.
##############################################

  FILENAME="$1"
# FILENAMES="$@"
# FILENAMES="$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS"

##################################################################
## Check that the selected file is a '.mp4' file.
##  (Assumes just one dot [.] in the filename, at the extension.)
##
##################################################################

FILEEXT=`echo "$FILENAME" | cut -d\. -f2`
 
if test "$FILEEXT" != "mp4"
then
   zenity --info --title "Input video suffix is not '.mp4'" \
   --no-wrap \
   --text  "\
The input video
   $FILENAME
suffix is not '.mp4'. Exiting."
   exit
fi

#############################################################################
## Prompt for the 'crop area' of the movie file in percents
## --- top, right, bottom, left.
#############################################################################


CROP_PCTS="0 0 30 0"

CROP_PCTS=$(zenity --entry \
   --title "CROP-MARGINS in %s: top,right,bottom,left" \
   --text "\
Enter CROP-MARGIN of the video frame in PERCENTS
--- top, right, bottom, left (clock-wise)
--- separated by single-spaces.

Example:
10 30 20 0 would cut
10% from the top
30% from the right
20% from the bottom
0% from the left

Enter null (delete input percents) to exit.
" \
   --entry-text "$CROP_PCTS")

if test "$CROP_PCTS" = ""
then
   exit
fi

PCT_TOP=`echo "$CROP_PCTS" | cut -d' ' -f1`
PCT_RGT=`echo "$CROP_PCTS" | cut -d' ' -f2`
PCT_BOT=`echo "$CROP_PCTS" | cut -d' ' -f3`
PCT_LFT=`echo "$CROP_PCTS" | cut -d' ' -f4`


#########################################################
## Get input video framesize (width and height in pixels)
## in vars IN_WID and IN_HGT --- using 'mediainfo'.
## References:
## https://stackoverflow.com/questions/7376477/getting-video-information-from-mediainfo
## https://superuser.com/questions/595177/how-to-retrieve-video-file-information-from-command-line-under-linux
## https://stackoverflow.com/questions/684015/how-can-i-get-the-resolution-width-and-height-for-a-video-file-from-a-linux-co?noredirect=1
## https://stackoverflow.com/questions/19091771/how-to-find-duration-of-a-video-file-using-mediainfo-in-seconds-or-other-formats
#########################################################

IN_WID=`mediainfo --Inform="Video;%Width%" "$FILENAME"`
IN_HGT=`mediainfo --Inform="Video;%Height%" "$FILENAME"`

#########################################################
## Alternatively:
## Get input video framesize (width and height in pixels)
## in vars IN_WID and IN_HGT --- using 'ffprobe'.
## Reference:
## https://stackoverflow.com/questions/7362130/getting-video-dimension-resolution-width-x-height-from-ffmpeg
## https://www.skillsugar.com/how-to-get-video-dimensions-with-ffmpeg
## https://askubuntu.com/questions/577090/one-liner-ffmpeg-or-other-to-get-only-resolution
## https://video.stackexchange.com/questions/16356/how-to-use-ffprobe-to-obtain-certain-information-about-mp4-h-264-files
#########################################################

# IN_WID=`ffprobe -v error -show_entries stream=width -of default=noprint_wrappers=1 "$FILENAME" | cut -d'=' -f2`
# IN_HGT=`ffprobe -v error -show_entries stream=height -of default=noprint_wrappers=1 "$FILENAME" | cut -d'=' -f2`

#########################################################
## Alternatively:
## Get input video framesize (width and height in pixels)
## in vars IN_WID and IN_HGT --- using 'ffmpeg'.
## Reference:
## https://superuser.com/questions/841235/how-do-i-use-ffmpeg-to-get-the-video-resolution
#########################################################

# IN_WID=`ffmpeg -i "$FILENAME" 2>&1 | grep Video: | grep -Po '\d{3,5}x\d{3,5}' | cut -d'x' -f1`
# IN_HGT=`ffmpeg -i "$FILENAME" 2>&1 | grep Video: | grep -Po '\d{3,5}x\d{3,5}' | cut -d'x' -f2`



#############################################
## Compute the ffmpeg '-filter:v' crop parms:
## OUT_WID, OUT_HGT, UPLFT_X, UPLFT_Y
#############################################
## Example crop command format:
## ffmpeg -i in.mp4 -filter:v "crop=out_w:out_h:x:y" -c:a copy out.mp4 
##
## Reference:
## https://video.stackexchange.com/questions/4563/how-can-i-crop-a-video-with-ffmpeg
####################################################################################

PX_TOP=$(( (PCT_TOP*IN_HGT)/100 ))
PX_RGT=$(( (PCT_RGT*IN_WID)/100 ))
PX_BOT=$(( (PCT_BOT*IN_HGT)/100 ))
PX_LFT=$(( (PCT_LFT*IN_WID)/100 ))

OUT_WID=$(( IN_WID - (PX_RGT + PX_LFT) ))
OUT_HGT=$(( IN_HGT - (PX_TOP + PX_BOT) ))
UPLFT_X=$(( PX_LFT ))
UPLFT_Y=$(( PX_TOP ))


###########################################
## Show the 4 calculated crop parameters and
## allow the user to change them or exit. 
###########################################

CROPPARMS="$OUT_WID $OUT_HGT $UPLFT_X $UPLFT_Y"

CROPPARMS=$(zenity --entry \
   --title "Check the crop parameters." \
   --text "\
According to 'mediainfo' command, the image
width and height are $IN_WID and $IN_HGT pixels.
   
The 4 crop parameters calculated from percentages are
OUT_WID = $OUT_WID
OUT_HGT = $OUT_HGT
UPLFT_X = $UPLFT_X
UPLFT_Y = $UPLFT_Y

Change them OR leave them unchanged ---
OR delete them to exit (cancel)." \
   --entry-text "$CROPPARMS")

if test "$CROPPARMS" = ""
then
   exit
fi

OUT_WID=`echo "$CROPPARMS" | cut -d' ' -f1`
OUT_HGT=`echo "$CROPPARMS" | cut -d' ' -f2`
UPLFT_X=`echo "$CROPPARMS" | cut -d' ' -f3`
UPLFT_Y=`echo "$CROPPARMS" | cut -d' ' -f4`

if test "$OUT_WID" = ""
then
   exit
fi


###############################
## Prepare the output filename.
###############################

FILEMIDNAME=`echo "$FILENAME" | cut -d\. -f1`

FILEOUT="${FILEMIDNAME}_CROPPED_${OUT_WID}x${OUT_HGT}.mp4"

if test -f "$FILEOUT"
then
   rm -f "$FILEOUT"
fi

###################################################################
## Use 'ffmpeg' to make the cropped 'mp4' file.
###################################################################

## FOR TEST:
#   set -x

xterm -hold -fg white -bg black -geometry 90x48+100+100 -e \
      $EXE_FFMPEG -i "$FILENAME" \
      -filter:v "crop=${OUT_WID}:${OUT_HGT}:${UPLFT_X}:${UPLFT_Y}" \
      -c:a copy "$FILEOUT"

## FOR TEST:
#    set -


###################################
## Show the (cropped) movie file.
##
## Note: If ffmpeg is installed,
## then ffplay should be installed.
###################################

if test ! -f "$FILEOUT"
then
   exit
fi

#  MOVIEPLAYER="/usr/bin/vlc"
#  MOVIEPLAYER="/usr/bin/mplayer"
#  MOVIEPLAYER="/usr/bin/gnome-mplayer"
#  MOVIEPLAYER="/usr/bin/totem"

MOVIEPLAYER="/usr/bin/ffplay -stats"

xterm -fg white -bg black -hold -geometry 90x24+100+100 -e \
      $MOVIEPLAYER "$FILEOUT"


##############################################
## Use a user-specified MOVIEPLAYER. Someday?
##############################################

#  . $HOME/.freedomenv/feNautilusScripts/set_DIR_NautilusScripts.shi
#  . $DIR_NautilusScripts/.set_VIEWERvars.shi

#   $MOVIEPLAYER "$FILEOUT" &