tc-video-generic: big refactoring using ffprobe

.scripts/tc-video-generic

@@ -141,12 +141,6 @@ if ! command -v ffmpeg >/dev/null; then
     exit
 fi
 
-_duration()
-{
-    ## In seconds.
-    ffmpeg -nostdin -i "$1" 2>&1 | awk '/Duration/ {split($2, time, /:|\./); print time[1]*60*60 + time[2]*60 + time[3]}'
-}
-
 _highfreq()
 {
     awk 'BEGIN{max=0} /crop=/ {t[$NF]++; if (t[$NF]>max) {max=t[$NF]; val=$NF}} END{print val}'
@@ -157,7 +151,7 @@ _cropvalue()
     ## For 5 different timeslices of 1 second at every 1/6th of the video, we
     ## sample the crop values. We keep the values with highest frequency. This
     ## is much faster than encoding in one pass with low framerate.
-    STEP=$(($(_duration "$1")/6))
+    STEP=$((${format_duration:-$streams_stream_0_duration}/6))
     for i in $(seq $STEP $STEP $((5*$STEP))); do
         ffmpeg -nostdin -ss $i -i "$1"  -t 10 -vf "cropdetect=24:2:0" -f null - 2>&1
     done | _highfreq
@@ -165,7 +159,7 @@ _cropvalue()
 
 _croppreview()
 {
-    STEP=$(($(_duration "$1")/6))
+    STEP=$((${format_duration:-$streams_stream_0_duration}/6))
     for i in $(seq  $STEP $STEP $((5*$STEP))); do
             ffmpeg -nostdin -v warning -y -ss $i -i "$1" \
                 -f image2 -vframes 1 $VIDEO_FILTER "${1%.*}-preview-$i-cropped.png" \
@@ -173,23 +167,29 @@ _croppreview()
     done
 }
 
+## Return the audio encoding parameters. For instance
+##  -c:2 libvorbis -b:2 384k -c:5 copy
+## If some stream bitrates are missing, we have two possibilities:
+## either we copy the stream (default), or we encode it to a default value.
 _audiobitrate()
 {
-    ## As of 2013-10-23, ffmpeg sucks at retrieving audio bitrate. Therefore we
-    ## use mediainfo if available, ffmpeg otherwise.
+    local bitrate
 
-    ## In the end, if some stream bitrates are missing, we have two
-    ## possibilities: either we copy the stream (default), or we encode it to a
-    ## default value.
+    for i in $(seq 0 $(($format_nb_streams-1)) ); do
+        ## Skip non audio tracks.
+        [ "$(eval echo \$streams_stream_${i}_codec_type)" != "audio" ] && continue
 
-    ## AWK note: in "(bitrate+0 > 500)", the +0 is required to make sure bitrate is numeric.
-    if command -v mediainfo >/dev/null; then
-        ## WARNING: mediainfo puts a space every 3 digits, hence the 'for' loop.
-        mediainfo "$1" | awk 'BEGIN {id=0} /^Audio/ { while(getline && ! index($0,"Bit rate  ") && NF != 0); for(i=4; i<NF; i++) res=res $i; print id, res; id++}'
-    else
-        ffmpeg -nostdin -i "$1" 2>&1 | awk 'BEGIN {id=0} /^ *Stream.*Audio/ {match($0, / [^ ]+ kb\/s/); res=substr($0, RSTART+1, RLENGTH-6); print id, res; id++}'
-    fi | awk -v codec="$AUDIO_CODEC" -v bitrate="$AUDIO_DEFAULT_RATE" \
-        '{if($2 || bitrate) {if($2) bitrate=$2; if(bitrate+0 > 500) bitrate=500; printf "-c:a:" $1 " " codec " -b:a:" $1 " " bitrate "k "} else printf "-c:a:" $1 " copy "} END {print ""}'
+        bitrate=$(( $(eval echo \$streams_stream_${i}_bit_rate) / 1000))
+        if [ -z "$bitrate" ] || [ "$bitrate" -le 0 ]; then
+            bitrate="$AUDIO_DEFAULT_RATE"
+        fi
+        if [ -n "$bitrate" ] && [ "$bitrate" -gt 0 ]; then
+            [ $bitrate -gt 500 ] && bitrate=500
+            printf -- "-c:%s %s -b:%s %sk " $i "$AUDIO_CODEC" $i "$bitrate"
+        else
+            printf -- "-c:%s copy " $i
+        fi
+    done
 }
 
 _transcode()
@@ -198,10 +198,18 @@ _transcode()
     OUTPUT="${1%.*}.$EXT"
     [ -e "$OUTPUT" ] && OUTPUT="${1%.*}-$(date '+%F-%H%M%S').$EXT"
 
+    ## Metadata (i.e. tags + technical data).
+    _buffer="$(ffprobe -v quiet -print_format flat=s=_ -show_streams -show_format "$1")"
+    if [ $? -ne 0 ]; then
+        _error "File [$1] is unsupported by FFmpeg."
+        return
+    fi
+    eval "$_buffer"
+    unset _buffer
+
     STREAM_TITLE=""
     if $OPT_REMOVE_TITLE; then
-        STREAM_NUM=$(ffmpeg -nostdin -i "$1" 2>&1 | grep -c 'Stream')
-        for i in $(seq 0 $STREAM_NUM); do
+        for i in $(seq 0 $(($format_nb_streams-1)) ); do
             STREAM_TITLE="${STREAM_TITLE}-metadata:s:$i title= "
         done
     fi
@@ -237,11 +245,6 @@ EOF
 
     $OPT_PREVIEW && return
 
-    ## Zsh compatibility. We need it otherwise word splitting of parameter like
-    ## SAMPLE will not work.
-    STATUS="$(set -o | awk '/shwordsplit / {print $2}')"
-    [ "$STATUS" = "off" ] && set -o shwordsplit
-
     ffmpeg -nostdin $OVERWRITE -i "$1" \
         $VIDEO_PARAM $VIDEO_FILTER \
         $AUDIO_PARAM \
@@ -249,10 +252,6 @@ EOF
         -map 0 $STREAM_TITLE \
         $SAMPLE $TC_VIDEO_OPT "$OUTPUT"
 
-    ## Restore Zsh previous options. This will not turn off shwordsplit if it
-    ## was on before calling the function.
-    [ "$STATUS" = "off" ] && set +o shwordsplit
-
     if $OPT_OVERWRITE; then
         rm "$1"
         mv -f "$OUTPUT" "${1%.*}.$EXT"