MediaCMS backend, initial commit

files/backends.py

@@ -0,0 +1,77 @@
+# ffmpeg only backend
+
+from subprocess import PIPE, Popen
+import locale
+import re
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class VideoEncodingError(Exception):
+    def __init__(self, *args, **kwargs):
+        self.message = args[0]
+        super(VideoEncodingError, self).__init__(*args, **kwargs)
+
+
+RE_TIMECODE = re.compile(r"time=(\d+:\d+:\d+.\d+)")
+console_encoding = locale.getdefaultlocale()[1] or "UTF-8"
+
+
+class FFmpegBackend(object):
+    name = "FFmpeg"
+
+    def __init__(self):
+        pass
+
+    def _spawn(self, cmd):
+        try:
+            return Popen(
+                cmd,
+                shell=False,
+                stdin=PIPE,
+                stdout=PIPE,
+                stderr=PIPE,
+                close_fds=True,
+            )
+        except OSError as e:
+            raise VideoEncodingError("Error while running ffmpeg", e)
+
+    def _check_returncode(self, process):
+        ret = {}
+        stdout, stderr = process.communicate()
+        ret["code"] = process.returncode
+        return ret
+
+    def encode(self, cmd):
+        process = self._spawn(cmd)
+        buf = output = ""
+        while True:
+            out = process.stderr.read(10)
+
+            if not out:
+                break
+            try:
+                out = out.decode(console_encoding)
+            except UnicodeDecodeError:
+                out = ""
+            output = output[-500:] + out
+            buf = buf[-500:] + out
+            try:
+                line, buf = buf.split("\r", 1)
+            except BaseException:
+                continue
+
+            progress = RE_TIMECODE.findall(line)
+            if progress:
+                progress = progress[0]
+            yield progress
+
+        process_check = self._check_returncode(process)
+        if process_check["code"] != 0:
+            raise VideoEncodingError(output[-1000:])  # output could be huge
+
+        if not output:
+            raise VideoEncodingError("No output from FFmpeg.")
+
+        yield output[-1000:]  # output could be huge