convert-help.sh

#!/bin/bash

INFILE=$1
VIDEXT=webm
OUTFILE="$INFILE.$VIDEXT"

VIDEO_BITRATE=850k  # higher is better quality
OUTPUT_RES=1280x720
CQ_MODE=10  # lower is better quality - VP9 only, -crf $CQ_MODE
AUDIO_QUALITY=4  # higher is better quality
AUDIO_SAMPLE_RATE=44100  # higher is better quality
AUDIO_TRACKS=1  # 2 for stereo
GOP=150  # affects seek points; lower = better seeking but bigger file

START=`date +%s`
echo "starting to convert $INFILE"
avconv -y \
        -i $INFILE \
        -c:v libvpx-vp9 \
        -b:v $VIDEO_BITRATE \
        -crf $CQ_MODE \
        -g $GOP \
        -s $OUTPUT_RES \
        -qmin 0 -qmax 50 \
        -c:a libvorbis \
        -q:a $AUDIO_QUALITY \
        -ar $AUDIO_SAMPLE_RATE \
        -ac $AUDIO_TRACKS \
        $OUTFILE

END=`date +%s`
ELAPSED=$(($END-$START))

INFILE_SIZE=`ls -lG $INFILE | cut -f4 -d' '`
OUTFILE_SIZE=`ls -lG $OUTFILE | cut -f4 -d' '`
INFILE_SIZE_HUMAN=`ls -lGh $INFILE | cut -f4 -d' '`
OUTFILE_SIZE_HUMAN=`ls -lGh $OUTFILE | cut -f4 -d' '`
PERCENTAGE=`echo '100 *' $OUTFILE_SIZE / $INFILE_SIZE | bc`

echo "$ID: Original size: $INFILE_SIZE_HUMAN Transcoded size: $OUTFILE_SIZE_HUMAN ($PERCENTAGE% of original)"
echo "$ID: `date -u -d @"$ELAPSED" +'%-H:%M:%S'` elapsed."

Makefile

V=0
VERBOSE = $(VERBOSE_$(V))
VERBOSE_0 = @echo "  GEN  $@";
VERBOSE_1 =

VIDEXT = webm

video_names = \
	endless-01-desktop.m4v   endless-08-offline.m4v \
	endless-02-folders.m4v   endless-09-writer.m4v  \
	endless-03-programs.m4v  endless-10-video-player.m4v \
	endless-04-wifi.m4v      endless-11-photos-and-music.m4v \
	endless-05-files.m4v     endless-12-social-bar.m4v \
	endless-06-browser.m4v   endless-13-printers.m4v \
	endless-07-windows.m4v
converted_video_names = $(addsuffix .$(VIDEXT),$(video_names))
videos = \
	$(addprefix es-compressed/,$(converted_video_names)) \
	original/Tutorial_1.mov.webm \
	original/Tutorial_2.mov.webm \
	original/Tutorial_3.mov.webm \
	original/Tutorial_4.mov.webm \
	original/Tutorial_5.mov.webm \
	original/Tutorial_6.mov.webm \
	original/Tutorial_7.mov.webm \
	original/Tutorial_8.mov.webm \
	original/Tutorial_9.mov.webm \
	original/Tutorial_10.mov.webm \
	original/Tutorial_11.mov.webm \
	original/Tutorial_12.mov.webm \
	original/Tutorial_13.mov.webm

#V      $(addprefix en-compressed/,$(converted_video_names)) \

all: $(videos)

clean:
	rm logs/* \
		en-compressed/*.$(VIDEXT) \
		es-compressed/*.$(VIDEXT) \
		original/*.$(VIDEXT)

%.$(VIDEXT):
	$(VERBOSE)mkdir -p logs/ && \
	./convert-help.sh $* > logs/$*.log && \
	tail -n2 logs/$*.log

.PHONY: all clean