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ffmpeg-mythtv
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a draft of split+scale+... transcoder

This commit is contained in:
Leo Butler 2021-01-21 20:33:41 -06:00
parent 084cc7f63f
commit 22319f14a3
1 changed files with 44 additions and 0 deletions
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44
ffmpeg-myth.scm
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@ -18,6 +18,7 @@
(define ffmpeg-bin "/usr/bin/ffmpeg")
(define ffprobe-bin "/usr/bin/ffprobe")
(define ffprobe-separator #\page) ;;
(define ffmpeg-transcoding-options "-preset slow -crf 21 -c:a ac3 -g 60 -keyint_min 30")
(define recordings-directory "/var/lib/mythtv/recordings")
(define working-directory "/mnt/lvraid5/ffmpeg-cut-list.d")
(define mythtv-recorded-table->metadata-list '(chanid starttime endtime title subtitle description season episode recordid seriesid programid inetref previouslyshown originalairdate))
@ -267,6 +268,49 @@
(assv-ref (recording-recorded-table rec) 'basename))
(define (recording-filesize rec)
(assv-ref (recording-recorded-table rec) 'filesize))
(define (recording-av-stream-info rec type)
(define (rvsi s r) (cond ((null? s) r)
((eqv? (assv-ref (car s) 'codec_type) type)
(rvsi (cdr s) (cons (car s) r)))
(#t (rvsi (cdr s) r))))
(rvsi (recording-streams-info rec) '()))
(define (recording-video-stream-ffmpeg-filt rec scale?)
(define (iter f l i acc)
(cond ((null? l) (reverse acc))
(#t
(iter f (cdr l) (+ 1 i) (cons (f i) acc)))))
(let* ((v (car (recording-av-stream-info rec 'video)))
(a (reverse (recording-av-stream-info rec 'audio)))
(rtn (recording-retain-list rec))
;;(sar (assv-ref v 'sample_aspect_ratio))
(dar (assv-ref v 'display_aspect_ratio))
(height (assv-ref v 'height))
(width (assv-ref v 'width))
(idx (assv-ref v 'index))
(aidx (map (lambda(s) (assv-ref s 'index)) a))
(scale-flt (if scale? (let ((fmt (simple-format #f "[~~a:~a] scale=w=~a:h=~a,setdar=~a,setpts=PTS-STARTPTS [v~~a];" idx width height dar)))
(lambda (i) (simple-format #f fmt i i))) (lambda (i) "")))
(av-ptr (lambda (i) (string-join (cons (if scale? (simple-format #f "[v~a]" i) (simple-format #f "[~a:~a]" idx i)) (map (lambda (a) (simple-format #f "[~a:~a]" i a)) aidx)))))
(out-ptr (lambda (i) (simple-format #f "[out~a]" i)))
(n (length rtn))
(concat (simple-format #f "concat=n=~a:v=1:a=~a [out0]" n (length aidx)))
(mappings (lambda (i) (simple-format #f "-map '[out~a]'" i))))
(string-join (append (list "'") (iter scale-flt rtn 0 '()) (iter av-ptr rtn 0 '()) (list concat) (iter out-ptr aidx 1 '()) (list "' ") (iter mappings (cons 0 aidx) 0 '())))))
(define* (ffmpeg-split+scale+transcode-recording rec #:optional (scale? #f))
(let* ((basename (recording-basename rec))
(rootname+ext (string-split basename #\.))
(rootname (car rootname+ext)) (ext (cadr rootname+ext))
(in-file (simple-format #f "~a/~a" recordings-directory basename))
(out-file (simple-format #f "~a/~a.~a" working-directory rootname transcoded-file-ending))
(m-d (mythtv-recorded-table->metadata rec))
(cut-times (myth-convert-i-frame-indices-to-times (recording-retain-list rec) (recording-i-frame-info rec)))
(seek-fn (lambda(c) (simple-format #f " -ss ~a -t ~a -i '~a'" (car c) (- (cdr c) (car c)) in-file)))
(filter (recording-video-stream-ffmpeg-filt rec scale?))
(options ffmpeg-transcoding-options)
(cmd (simple-format #f "~a -y ~a -filter_complex ~a ~a ~a ~a" ffmpeg-bin (string-join (map seek-fn cut-times)) filter options m-d out-file)))
(shell-command-to-string cmd)
cmd))
(define (recording-new-file-name file-name ending)
(let* ((old-ending (substring file-name (- (string-length file-name) 3)))