Converting Audio on 500+ MP4s (Movies)

discostu212

macrumors newbie
Original poster
Mar 24, 2012
7
0
Hi All,
I've been searching for a while and I cannot find a solution to this predicament, I am hoping the experts on this forum can provide me with some advice.

I've converted my movie library to MP4/M4V for use with the appletv2, however I just realized that AAC 6 channels does not give me Dolby Digital on my receiver (I only get Pro Logic). Apparently I need AC3 - 6 channels and AAC 2 Channel to get Dolby Digital. I tried using MP4 tools but I am getting a lot of errors (its the registered version).

Any ideas on software (Mac or PC) that can do this for me without re-encoding the video (batch encoding required).
 

discostu212

macrumors newbie
Original poster
Mar 24, 2012
7
0
The Audio is currently in AAC 6 channels. I need it to be AC3 6 channels and and AAC 2 channels. I hope this makes sense.
 

martinm0

macrumors 6502a
Feb 27, 2010
563
25
The Audio is currently in AAC 6 channels. I need it to be AC3 6 channels and and AAC 2 channels. I hope this makes sense.
It might be easier just upgrading your receiver. I have to think that if you have AAC 6ch, its because your original movies weren't initially AC3 5.1 (maybe DTS?). I don't know that you can go AAC 6ch to AC3 5.1 (I'm just guessing here).

I too converted hundreds of movies and found that my old Onkyo didn't output as 5.1. I've upgraded since then and all the new receivers seem to handle the AAC format without issue.

Great deals at Accessories4less.com on refurb receivers.
 

discostu212

macrumors newbie
Original poster
Mar 24, 2012
7
0
New replacements will not be an option for the 3 systems in the house as I am currently out of a job.

There must be a solution to this problem..
 

Busta999

macrumors newbie
Apr 15, 2010
23
1
Not sure if this will solve the problem, but it looks like a job for IVI.

It will take the file, keep the H.264 and convert the audio according to your specifications, and as I recall keep the original audio as well.

It is a great tool I use a lot , converting my DVDs to online for access by the AppleTV
 

here2rock

macrumors regular
Mar 23, 2012
170
0
Australia
If you still have the original source you could use MkvToMp4 (pc) to have two audio tracks.

If you don't then you could use Avidemux for Dolby Pro Logic Sound.
 

Diveflo

macrumors regular
Mar 12, 2008
168
3
If you have a Windows machine I could give you a batch file I created for exactly this. It uses eac3to and mp4box. But keep in mind that remuxing will remove any metadata you have added to the file...I have yet to find a solution to this...
 

everygeek

macrumors newbie
Mar 22, 2012
11
0
I've actually been doing the same thing recently.

From what I've found out it's easy to go AC3 - AAC 5.1, but going the other way is difficult because the channels often get messed up.

MP4Tools should be able to do it as I was using it for a bit. What errors is it giving you?
 

discostu212

macrumors newbie
Original poster
Mar 24, 2012
7
0
The audio conversion would get messed up. For a 2 hour movie, I'll end up with a 10 second audio track. Tried a batch conversion for 10 movies, the few that were processed ended up with the audio problem, and the rest just said error.
 

Clark Kent

macrumors member
Mar 31, 2009
75
0
MP4Tools should be able to do it as I was using it for a bit. What errors is it giving you?
MP4Tools works perfectly for this task 95% of the time. The other 5% of the time you will get audio that is slightly out of sync. This has been happening to me as I convert my MKV videos to MP4, including changing either DTS or AAC to AC3 and adding a 2 channel AAC track.

When it's out of sync, I've used a combination of MP4Tools, Remux, and Subler (all free programs) to get the job done. I pulled out the AAC or DTS track with MP4Tools, used Subler to put it back into the original file so it had two identical tracks, then used Remux to transcode the audio to AC3 and 2 channel. I'm sure there is an easier way, but that worked to get me what I wanted without sync issues.

Thankfully this has been necessary on 2 or 3 movies out of the 25 or so I've converted so far. For the rest, MP4Tools did everything perfectly in one attempt.
 

discostu212

macrumors newbie
Original poster
Mar 24, 2012
7
0
If you have a Windows machine I could give you a batch file I created for exactly this. It uses eac3to and mp4box. But keep in mind that remuxing will remove any metadata you have added to the file...I have yet to find a solution to this...
I would really appreciate that.
 

discostu212

macrumors newbie
Original poster
Mar 24, 2012
7
0
Could you post the output of MediaInfo(Google) of one of your files? That way I can adjust my script. Got an exam tomorrow, but after that I can get on it.

Sorry for the delay. Just to confirm all the audio files are not exactly the same. ie. Might have different bitrates etc. I hope it doesn't cause a problem. Here is the data from mediainfo:

General
Complete name : /Volumes/FreeAgent GoFlex Drive/Movies 2/Dr.Strangelove.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 4.16 GiB
Duration : 1h 34mn
Overall bit rate mode : Variable
Overall bit rate : 6 285 Kbps
Movie name : Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb
Part/Position : 0
Part/Total : 0
Track name/Position : 0
Track name/Total : 0
Performer : Peter Sellers, George C. Scott, Sterling Hayden, Slim Pickens, Keenan Wynn, Peter Bull, Jack Creley, Tracy Reed
Genre : Drama
Recorded date : 1964-01-29
Encoded date : UTC 2012-03-20 08:05:00
Tagged date : UTC 2012-03-21 00:20:19
Cover : Yes
desc : An insane general starts a process to nuclear holocaust that a war room of politicians and generals frantically try to stop. A classic black and white war satire from director Stanley Kubrick starring Peter Sellers.
ldes : An insane general starts a process to nuclear holocaust that a war room of politicians and generals frantically try to stop. A classic black and white war satire from director Stanley Kubrick starring Peter Sellers.
hdvd : 1
stik : 9
rtng : 0
iTunEXTC : au-tv|PG|400|
iTunMOVI : <?xml version="1.0" encoding="UTF-8"?> / <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> / <plist version="1.0"> / <dict> / <key>cast</key> / <array> / <dict> / <key>name</key> / <string>Peter Sellers</string> / </dict> / <dict> / <key>name</key> / <string>George C. Scott</string> / </dict> / <dict> / <key>name</key> / <string>Sterling Hayden</string> / </dict> / <dict> / <key>name</key> / <string>Slim Pickens</string> / </dict> / <dict> / <key>name</key> / <string>Keenan Wynn</string> / </dict> / <dict> / <key>name</key> / <string>Peter Bull</string> / </dict> / <dict> / <key>name</key> / <string>Jack Creley</string> / </dict> / <dict> / <key>name</key> / <string>Tracy Reed</string> / </dict> / </array> / <key>directors</key> / <array> / <dict> / <key>name</key> / <string>Stanley Kubrick</string> / </dict> / </array> / <key>producers</key> / <array> / <dict> / <key>name</key> / <string>Leon Minoff</string> / </dict> / <dict> / <key>name</key> / <string>Stanley Kubrick</string> / </dict> / <dict> / <key>name</key> / <string>Victor Lyndon</string> / </dict> / </array> / <key>screenwriters</key> / <array> / <dict> / <key>name</key> / <string>Peter George</string> / </dict> / <dict> / <key>name</key> / <string>Terry Southern</string> / </dict> / <dict> / <key>name</key> / <string>Peter George</string> / </dict> / <dict> / <key>name</key> / <string>Stanley Kubrick</string> / </dict> / </array> / <key>studio</key> / <string>Columbia Pictures Corporation , Hawk Films</string> / </dict> / </plist>

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 5 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1h 34mn
Bit rate mode : Variable
Bit rate : 5 964 Kbps
Width : 1 200 pixels
Height : 720 pixels
Display aspect ratio : 1.667
Frame rate mode : Variable
Frame rate : 23.976 fps
Minimum frame rate : 23.810 fps
Maximum frame rate : 24.390 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.288
Stream size : 3.95 GiB (95%)
Writing library : x264 core 67 r1153M 7b6ce6a
Encoding settings : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x2 / me=umh / subme=7 / psy_rd=1.0:0.0 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / chroma_qp_offset=-2 / threads=6 / nr=0 / decimate=1 / mbaff=0 / bframes=3 / b_pyramid=1 / b_adapt=1 / b_bias=0 / direct=1 / wpredb=1 / keyint=250 / keyint_min=25 / scenecut=40 / rc=2pass / bitrate=5964 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00
Encoded date : UTC 2012-03-20 08:05:00
Tagged date : UTC 2012-03-20 08:16:20

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 1h 34mn
Bit rate mode : Variable
Bit rate : 315 Kbps
Maximum bit rate : 412 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Compression mode : Lossy
Stream size : 213 MiB (5%)
Language : English
Encoded date : UTC 2012-03-20 08:05:00
Tagged date : UTC 2012-03-20 08:16:22

Text
ID : 3
Format : Timed text
Muxing mode : sbtl
Codec ID : tx3g
Duration : 1h 32mn
Bit rate mode : Variable
Bit rate : 87 bps
Stream size : 58.9 KiB (0%)
Language : English
Encoded date : UTC 2012-03-20 08:05:00
Tagged date : UTC 2012-03-20 08:16:20