Started Python script plexoptimise.py that tries to automatically find

best ffmpeg parameters for conversion.

plexoptimise.py

@@ -0,0 +1,137 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from collections import OrderedDict
+from json import loads
+from pprint import pprint
+import subprocess
+import sys
+
+# Found: https://superuser.com/questions/852400/properly-downmix-5-1-to-stereo-using-ffmpeg
+# and http://forum.doom9.org/showthread.php?t=168267
+ATSC_MODE="pan=stereo|FL<1.0*FL+0.707*FC+0.707*BL|FR<1.0*FR+0.707*FC+0.707*BR"
+NIGHT_MODE="pan=stereo|FL=FC+0.30*FL+0.30*BL|FR=FC+0.30*FR+0.30*BR"
+STEREO="pan=stereo|c0=FL|c1=FR"
+
+FIRST_LANGUAGE="eng"      # first audio language
+DEFAULT_LANGUAGE="eng"    # assume this language if not set in metadata
+CRF="24"   # 18 - almost lossless, 22 - medium, 28 - low
+KEEP_VIDEO=["h264"]
+
+# https://stackoverflow.com/questions/3844430/how-to-get-the-duration-of-a-video-in-python
+def ffprobe(filepath):
+        command = [
+                "ffprobe",
+                "-loglevel",  "quiet",
+                "-print_format", "json",
+                "-show_format",
+                "-show_streams",
+                filepath
+        ]
+
+        pipe = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+        out, err = pipe.communicate()
+        return loads(out)
+
+def add_video_params(params, out_idx, stream):
+    if int(stream["height"]) > 720 or stream["codec_name"] != "h264":
+        params["c:v"] = "h264"
+        params["preset"] = "fast"
+        params["crf"] = CRF
+        # TODO: Might need some tweaking, not sure if it's really "mpeg4"
+        if stream["codec_name"] == "mpeg4":
+            params["bsf:v"] = "mpeg4_unpack_bframes"
+        if int(stream["height"]) > 720:
+            # Correct aspect ratio and rescale to 720
+            params["filter_complex"].append("[0:{}]scale=iw*sar:ih,scale=-2:720,setsar=1:1".format(stream["index"]))
+        else:
+            # Just correct aspect ratio if needed
+            params["filter_complex"].append("[0:{}]scale=iw*sar:ih,setsar=1:1".format(stream["index"]))
+    else:
+        params["filter_complex"].append("[0:{}]null".format(stream["index"]))
+        params["c:v"] = "copy"
+    params["movflags"] = "+faststart"
+    if stream["field_order"] != "progressive":
+        fc = params["filter_complex"].pop()
+        fc += ",yadif=1"   # 1 = use detected field_order, doubles framerate / 0 = merge both fields into frame, keeps framerate
+        # To force field_order: 1:0 (top field first) or 1:1 (bottom field first) / -field-dominance 0 or -field-dominance 1
+        params["filter_complex"].append(fc)
+
+def add_audio_params(params, out_idx, stream):
+    params["c:a"] = "aac"
+    params["b:a"] = "96k"
+    params["ar"] = "44100"
+    params["ac"] = "2"
+    if stream["channel_layout"] != "stereo":
+        params["filter_complex"].append("[0:{}]{}".format(stream["index"], NIGHT_MODE))
+    else:
+        params["filter_complex"].append("[0:{}]{}".format(stream["index"], STEREO))
+    params["metadata:s:{}".format(out_idx)] = "language={}".format(stream["tags"]["language"])
+
+def add_sub_params(params, out_idx, stream):
+    pass
+
+def build_ffmpeg_cmd(params):
+    cmd = ["nice", "ffmpeg", "-i", "\"{}\"".format(FILENAME)]
+    for p, v in params.items():
+        cmd.append("-{}".format(p))
+        if p == "filter_complex":
+            cmd.append("\"{}\"".format(";".join(v)))
+        else:
+            cmd.append(v)
+    cmd.append("\"{}.mkv\"".format(FILENAME))
+    return cmd
+
+FILENAME = sys.argv[1]
+
+data = ffprobe(FILENAME)
+pprint(data)
+
+video_streams = []
+audio_streams = []
+other_streams = []
+for s in data["streams"]:
+    codec = s["codec_type"]
+    if not "tags" in s:
+        s["tags"] = {
+            "language": DEFAULT_LANGUAGE
+        }
+    elif not "language" in s["tags"]:
+        s["tags"]["language"] = DEFAULT_LANGUAGE
+    if codec == "video":
+        video_streams.append(s)
+    elif codec == "audio":
+        audio_streams.append(s)
+    else:
+        other_streams.append(s)
+
+# Make sure first audio is FIRST_LANGUAGE
+if audio_streams[0]["tags"]["language"] != FIRST_LANGUAGE:
+    for i, s in enumerate(audio_streams):
+        if s["tags"]["language"] == FIRST_LANGUAGE:
+            del audio_streams[i]
+            audio_streams.insert(0, s)
+            break
+
+output_streams = video_streams + audio_streams + other_streams
+
+# Now process streams in order to build command line
+params = OrderedDict({
+    "map": "0",
+    "filter_complex": []
+})
+for i, s in enumerate(output_streams):
+    codec = s["codec_type"]
+    if codec == "video":
+        add_video_params(params, i, s)
+    elif codec == "audio":
+        add_audio_params(params, i, s)
+    elif codec == "subtitle":
+        add_sub_params(params, i, s)
+    else:
+        print("Unknown codec_type: {}".format(codec))
+
+cmd = build_ffmpeg_cmd(params)
+
+pprint(output_streams)
+print(" ".join(cmd))

plexoptimize.sh

@@ -3,6 +3,13 @@ if [ -z "$1" ]; then
     echo "Syntax: $0 VIDEOFILE [SUBTITLEFILE]"
     exit 1
 fi
+
+# Found: https://superuser.com/questions/852400/properly-downmix-5-1-to-stereo-using-ffmpeg
+# and http://forum.doom9.org/showthread.php?t=168267
+ATSC_MODE="pan=stereo|FL<1.0*FL+0.707*FC+0.707*BL|FR<1.0*FR+0.707*FC+0.707*BR"
+NIGHT_MODE="pan=stereo|FL=FC+0.30*FL+0.30*BL|FR=FC+0.30*FR+0.30*BR"
+STEREO="pan=stereo|c0=FL|c1=FR"
+
 SUBPARAMS=( )
 if [ -n "$2" ]; then
     # http://stackoverflow.com/questions/8672809/use-ffmpeg-to-add-text-subtitles
@@ -20,6 +27,8 @@ fi
 #ffmpeg -i "$1" "${SUBPARAMS[@]}" -c:v h264 -c:a libvo_aacenc -preset fast -movflags +faststart -crf 18 -b:a 192k -ac 2 "$1.mp4"
 #ffmpeg -i "$1" "${SUBPARAMS[@]}" -c:v h264 -c:a aac -preset fast -movflags +faststart -vf yadif=0,scale=-2:720 -crf 18 -b:a 160k -ar 44100 -ac 2 "$1.mp4"
 #ffmpeg -i "$1" "${SUBPARAMS[@]}" -c:v h264 -c:a aac -preset fast -movflags +faststart -vf scale=-2:720 -crf 20 -b:a 160k -ar 44100 -ac 2 "$1.mp4"
+#ffmpeg -i "$1" "${SUBPARAMS[@]}" -c:v h264 -c:a aac -preset fast -movflags +faststart -vf scale=-2:720 -crf 24 -b:a 96k -ar 44100 -ac 2 "$1.mp4"
 #ffmpeg -i "$1" "${SUBPARAMS[@]}" -c:v h264 -c:a aac -preset fast -movflags +faststart -crf 20 -b:a 160k -ar 44100 -ac 2 "$1.mp4"
-ffmpeg -i "$1" "${SUBPARAMS[@]}" -c:v h264 -c:a aac -preset fast -movflags +faststart -crf 25 -b:a 96k -ar 44100 -ac 2 "$1.mp4"
+ffmpeg -i "$1" "${SUBPARAMS[@]}" -c:v h264 -c:a aac -preset fast -movflags +faststart -crf 24 -b:a 96k -ar 44100 -ac 2 "$1.mp4"
 #ffmpeg -i "$1" "${SUBPARAMS[@]}" -c:v libx265 -c:a aac -preset fast -movflags +faststart -crf 20 -b:a 160k -ar 44100 -ac 2 "$1.x265.mp4"
+#ffmpeg -i "$1" "${SUBPARAMS[@]}" -map 0 -c:v h264 -c:a aac -preset fast -movflags +faststart -filter_complex "[0:v]scale=-2:720;[0:a:1]$NIGHT_MODE;[0:a:0]$STEREO" -metadata:s:a:0 language=eng -metadata:s:a:1 language=ger -crf 24 -b:a 96k -ar 44100 -ac 2 "$1.mkv"