From 2d0774abeb68769becbbf88e3a31a7f006c4e7aa Mon Sep 17 00:00:00 2001
From: spl0k <alban.feron@gmail.com>
Date: Tue, 15 Oct 2013 13:14:20 +0200
Subject: [PATCH] Transcoding

---
 api/media.py | 70 ++++++++++++++++++++++++++++++++++++++++++----------
 scanner.py   | 11 +++++++++
 2 files changed, 68 insertions(+), 13 deletions(-)

diff --git a/api/media.py b/api/media.py
index 2ed3b69..2c8f512 100755
--- a/api/media.py
+++ b/api/media.py
@@ -1,14 +1,23 @@
 # coding: utf-8
 
-from flask import request, send_file
+from flask import request, send_file, Response
 import os.path
 from PIL import Image
+import subprocess
 
-import config
+import config, scanner
 from web import app
 from db import Track, Folder, User, now, session
 from api import get_entity
 
+def prepare_transcoding_cmdline(base_cmdline, input_file, input_format, output_format, output_bitrate):
+	if not base_cmdline:
+		return None
+	ret = base_cmdline.split()
+	for i in xrange(len(ret)):
+		ret[i] = ret[i].replace('%srcpath', input_file).replace('%srcfmt', input_format).replace('%outfmt', output_format).replace('%outrate', str(output_bitrate))
+	return ret
+
 @app.route('/rest/stream.view', methods = [ 'GET', 'POST' ])
 def stream_media():
 	status, res = get_entity(request, Track)
@@ -19,20 +28,58 @@ def stream_media():
 	if format:
 		format = format.lower()
 
-	if format != 'raw':
+	do_transcoding = False
+	src_suffix = res.suffix()
+	dst_suffix = res.suffix()
+	dst_bitrate = res.bitrate
+	dst_mimetype = res.content_type
+
+	if format != 'raw': # That's from API 1.9.0 but whatever
 		if maxBitRate:
 			try:
 				maxBitRate = int(maxBitRate)
 			except:
 				return request.error_formatter(0, 'Invalid bitrate value')
 
-			if res.bitrate > maxBitRate:
-				# TODO transcode
-				pass
+			if dst_bitrate > maxBitRate and maxBitRate != 0:
+				do_transcoding = True
+				dst_bitrate = maxBitRate
 
-		if format and format != res.suffix():
-			# TODO transcode
-			pass
+		if format and format != src_suffix:
+			do_transcoding = True
+			dst_suffix = format
+			dst_mimetype = scanner.get_mime(dst_suffix)
+
+	if do_transcoding:
+		transcoder = config.get('transcoding', 'transcoder_{}_{}'.format(src_suffix, dst_suffix))
+		decoder = config.get('transcoding', 'decoder_' + src_suffix) or config.get('transcoding', 'decoder')
+		encoder = config.get('transcoding', 'encoder_' + dst_suffix) or config.get('transcoding', 'encoder')
+		if not transcoder and (not decoder or not encoder):
+			transcoder = config.get('transcoding', 'transcoder')
+			if not transcoder:
+				return request.error_formatter(0, 'No way to transcode from {} to {}'.format(src_suffix, dst_suffix))
+
+		transcoder, decoder, encoder = map(lambda x: prepare_transcoding_cmdline(x, res.path, src_suffix, dst_suffix, dst_bitrate), [ transcoder, decoder, encoder ])
+		if transcoder:
+			proc = subprocess.Popen(transcoder, stdout = subprocess.PIPE)
+		else:
+			dec_proc = subprocess.Popen(decoder, stdout = subprocess.PIPE)
+			proc = subprocess.Popen(encoder, stdin = dec_proc.stdout, stdout = subprocess.PIPE)
+
+		def transcode():
+			while True:
+				data = proc.stdout.read(8192)
+				if not data:
+					break
+				yield data
+			proc.terminate()
+			proc.wait()
+
+		response = Response(transcode(), mimetype = dst_mimetype)
+	else:
+		response = send_file(res.path)
+
+	# TODO handle estimateContentLength
 
 	res.play_count = res.play_count + 1
 	res.last_play = now()
@@ -40,10 +87,7 @@ def stream_media():
 	request.user.last_play_date = now()
 	session.commit()
 
-	if estimateContentLength == 'true':
-		return send_file(res.path), 200, { 'Content-Length': os.path.getsize(res.path) }
-
-	return send_file(res.path)
+	return response
 
 @app.route('/rest/download.view', methods = [ 'GET', 'POST' ])
 def download_media():
diff --git a/scanner.py b/scanner.py
index 552ac46..4d5f996 100755
--- a/scanner.py
+++ b/scanner.py
@@ -5,6 +5,17 @@ import time, mimetypes
 import mutagen
 import db
 
+def get_mime(ext):
+	ret = mimetypes.guess_type('dummy.' + ext, False)[0]
+	if ret:
+		return ret
+	try:
+		module = __import__('mutagen.' + ext, fromlist = [ 'Open' ])
+		inst = module.Open()
+		return inst.mime[0]
+	except:
+		return None
+
 class Scanner:
 	def __init__(self, session):
 		self.__session = session