by Morpheus » Mon May 08, 2017 8:15 pm
[quote="sam_buster"]Seems voting has closed but I would have voted for 720p compressed.
I also prefer stereo audio to 5.1ch - the difference in flie size is considerable, especially over mutiple movies, and for my needs the extra channels are overkill.
However Morpheus' comments might convince me to change my opinion of 5.1 - I too often struggle to pick out the dialogue in some movies.[/quote]
A quick "how to" (it doesn't have to be done this way, it's just a decent way i do it)
OK - ffmpeg and mktoolnix needed.
Made up filename - pop.mkv, video + 5.1 audio.
mkvtools - drop in the video, deselect everything BUT the audio file - hit [go] - result is pop.mka
edit script one to use that file name, run it.
Wait for it to finish and read the line
[Parsed_volumedetect_0 @ 0x7f8ba1c121a0] mean_volume: -16.0 dB
[Parsed_volumedetect_0 @ 0x7f8ba1c121a0] max_volume: -5.0 dB ***************** this line ignore the minus sign, you just want the numbers.
note the number - 5.0 as here.
edit script 2 to use the filename AND that number (you can edit the bitrate if you wish, 160 is a decent compromise between size and quality)... run it... wait for it to finish - result is pop.mp3
Now open mkvtools - drag both the original video file AND the new mp3 file into it
select only the video portion of the file and the mp3 (and chapters/subtitle if you have them) - deselect the original audio part of the file.
hit the [Go] button
result is a new mkv file with the stereo mp3 in in.
script 1 (copy it without the ******)
**************************
D:\Downloads\ffmpeg.exe -i "E:\Phantoms 1998 1080.ac3" -af volumedetect -f null -
pause
**************************
Edit the "d:/downloads..." to use your path to ffmpeg
edit the "Phantoms..." to your video filename.
"pause" is there to give you time to read the line.
script 2
**************************
D:\Downloads\ffmpeg.exe -i "E:\Phantoms 1998 1080.mka" -map 0:a:0 -f mp3 -acodec mp3 -b:a 160k -ac 2 -af pan=stereo:FL=0.25*FL+FC+0.6*LFE:FR=0.25*FR+FC+0.6*LFE -af "volume=2.2dB" "E:\Phantoms 1998 1080.mp3"
**************************
edit the path at the start
edit input filename
edit output filename
edit "volume=2.2dB" to match the number you found for your file
This will convert 5.1 to stereo with enhances centre speaky track AND normalise volume (so many have low volumes... I've had my TV up to 95/100 and still hard to hear on some films)
if you don't want volume changes then delete the bit ---
-af "volume=2.2dB"
****************
OK?
Test samples:
original
s000.tinyu---pload---com/index.php?file_id=02790976580636914033
Basic 5.1 THX video sample
"fixed"
s000.tinyu---pload---com/index.php?file_id=00584560659435399499
now stereo and with a 9.1 db boost.
Try running the first file through the scripts.
EFFINg hell... "not permitted to post links"...
OK... remove the "---"