Encoding for Apple TV

[hkaplan131]

I want to encode video/audio to send (sync) via iTunes to my Apple TV. Apple TV requires mpeg-4. The video format is not the issue. I have used MP4 H.264 with good results. My issue is with the audio. The Apple TV is suppose to support AC3 (Dolby Digital 5.1) and I want to send over this audio format. I selected 'passthrough' since the source I want to encode shows AC3 as the format. There is no need for the file created to be able to be played on the iMac, so if it comes up with a non-playable format on the iMac I am not concerned.

I selected 'passthrough' as the audio format. I noted the the 'encode audio' checkbox next to the audio pull down remained checked after I selected 'passthrough' and I left it that way. I ran the encode. I dropped the the .mp4 output file on the input window of fmmpegX to check it and the video was as expected, but the audio was conceverted to AA3 stereo to my surprise. I confirmed this by sending the file to the Apple TV and playing it. My reciever shows the optical audio stream format and it indicated it was NOT AC3 format!

Am I suppose to uncheck the 'encode audio' box to get the AC3 format to come thorugh to the output file?

Any help would be appreciated. Also, if anyone has worked with the Apple TV and knows the best video output format, that information would be appreciated.

Thanks,
Howard

[Case]

Have you tried, after a H.264 conversion, to open in QucikTime Pro, replace the AAC audio track with the AC3, then saving as .mov?
I don't have an Apple TV box to test on, but I'm curious of the result, if you would be so kind as to try my test file (10.5 MB).

[hkaplan131]

Case,

I was out of town for a few days and just picked up your forum reply. I do not have QuickTime Pro so I cannot try your suggestion. I did download your test file which has AC-3 audio. As expected the audio will not play on my iMac. I sent the file via iTunes over to the Apple TV and to my surprise there was no audio. I am still running ATV v1.1 firmware and have not been able to get the ATV to play AC-3 sound. I know my Home Theater work fine with AC-3. I use it all the time.

I also tried converted the file yo sent to AA3 audio using ffmegX. The video is fine, but again no audio. Not sure, but perhaps the file you made available might not have a good sound track. QuickTime and ffmegX both say the track is AC-3.

Any ideas?

Howard

[russkelp]

The Apple Tv is supposed to support DD 5.1, but not until the new firmware hits at the end of February.

I guess we'll have to wait for that update before we can figure out what process works.

[paul_jefferson]

Hey guy's I have the same kind of problem, I want to create movie files to stream to my Apple Tv with ac3 soundtracks.

I downloaded the movie case provided, it worked a treat, all the lights and relays on my amp clicked over to Dolby Digital when I played the video.

The Apple tv has always been able to play ac3 (Dolby Digital/DTS), even the first firmware. Providing your kit has a digital connection you can get ac3 through.

I have some sound tracks in iTunes that are DTS, they sound funny if you play them in iTunes, a bit like a an old audio cassette computer game sounded.

I guess my question is, If I rip a movie using handbrake or ffmpeg, how do I get the ac3 soundtrack out of the original using Quick Time Pro?

Could you give a step by step on how you created that Dolby City movie clip?


Cheers


Paul

[Case]

I downloaded the movie case provided, it worked a treat, all the lights and relays on my amp clicked over to Dolby Digital when I played the video.

Great, glad to hear that.

If I rip a movie using handbrake or ffmpeg, how do I get the ac3 soundtrack out of the original using Quick Time Pro?

1/ Convert your source movie to .mp4 with AAC audio as usual.
2/ Extract the AC3 sound from the source. (Demux)
3/ Open the .mp4 in QTP, Cmd-J, select the audio track, delete the audio track.
4/ Open the .ac3 in QTP, copy-and-paste to the .mp4 file
(Select all, copy, switch to other window, select all, add to movie)
(Opening ac3 files in QuickTime requires the A52Codec, which is available as a separate download or bundled with Perian)
5/ Save as (self-contained .mov)

[hkaplan131]

The easiest way is to use the latest version of Visual Hub which has an AppeTV built-in preset for Dolby 5.1. One step and you are done. Cost $23 though. FFmegX and Handbrake both require mutiple passes at this time. I expect a new version of Handbrake and FFmegX will add AppleTV Dolby 5.1 (AC3) presets eventually.

Howard

[paul_jefferson]

Being new to video and video codecs. What is the best way to (Demux) is there a product or can I use? perhaps ffmpeg?

[paul_jefferson]

Handbrake and ffmpeg just pass parameters to other tools for you, presumably if we can find out the parameters we can just knock up a shell script to do that. I am a shell programmer, so I don't mind knocking up something if I new the params.

[Case]

What is the best way to (Demux) is there a product or can I use? perhaps ffmpeg?

It depends on your source file. For .mpg or .vob files, MPEG Streamclip is good at demuxing. bbDemux is a good alternative. ffmpegX also has a MPG/VOB demux tool.
For .avi or .mpg files, D-Vision can extract audio streams (Tools>Misc. Tools>Rencoding .avi and .mpg>Copy/Extract>Extraction of an audio track>Settings).
Also QuickTime Pro can extract audio streams out of AVIs (Cmd-J).

[InsanelyOne]

Does anyone know if there is a bitrate limit on AC3 audio and the Apple TV? I've got quite a few HD movies I used Visual Hub to create MOV files with AC3 audio. All but 3 of them work just fine. The 3 that don't work play the video flawlessly but the audio is gone or I get occasional hisses and pops. I've discovered that the 3 in question all have audio bitrates > 448 Kbps. Do you think it's a limitation of the Apple TV... or maybe my A/V receiver?

[jar]

Hello Guys,

I'm having the same problem in my apple TV.

I've got some HD Videos in Matroska format (MKV). When I play it on the computer, the AC3 filter shows me that they are trully in AC3 format. However, when I try to convert it to Apple TV format, my encoders simply don't give me the option to reencode the AC3 format. They only option is the ACC-LC (Low Complexity) or ACC.

I've used: RIVER PAST VIDEO CLEANER PRO, IMTOO APPLE TV VIDEO CONVERTER 3 PRO, WONDERSHARE VIDEO CONVERTER PLATINUM, CUCUSOFT APPLE TV VIDEO CONVERTER under WINDOWS XP.

I've tried VisualHub too under MAC OS. In this software, there is an option to encode in "Apple TV 5.1" format. I did it, but when i send the file to Apple TV, the sound didn't play.

Apple TV, however, does play AC3 format!!! I've riped a DVD with dolby digital sound using Handbrake. It worked fine. Handbraked created a M4V file. I checked the file on GSspot, that shows me the audio format: AC3. Finally, I send the file to Apple TV, and my receiver lights up showing that it was playing an AC3 audio.

If anyone knows how to convert an "AC3 5.1 Matroska file" to "apple tv 5.1" directly, we will apriciate.

[gwire]

Hello! In response to jar. After extensive searching it seems I just cant find enough information about this topic. I have been trying to accomplish this same conversion for the Apple TV. This is what I have put together.

1. You can convert a MKV file with ac3 using VisualHub. Just click on the advanced button and in the audio section click the dropdown arow and select (passthrough). Atv will pass the ac3 info for your reciever to decode. I have done it, it works, verry simple. It just takes 12 or more hours depending on your computer power to transcode.

2. My big problem is this! I have alot of MKV files with AAC 6 chanel audio. I have successfuly been able to demux and convert the AAC audio to AC3 Audio using graphEdit using the instructions from this link. (you must have ffdshow installed).
Link: http://forum.doom9.org/showthread.php?p=666230#post666230

3. I then Use VisualHub to convert the MKV File to a MP4 file with AAC. Unfortunately there are no recievers that can decode passthrough AAC, except for this one Dennon in Japan that I came accross, wich is way to expensive for a Solution.

4. Finally I used quicktime Pro. I open the MP4 file (the one I just trancoded from the MKV file in VisualHub 12 hours later). Then using the instructions above I delete the AAC audio stream and Past the new AC3 stream I created with Graphedit. then just add to Itunes Library, sync with Apple TV. WALA!! My Yamaha RX V800 Decodes in AC3 DD.

I hope this helps because this is the only thread i found that comes close to what I want to accomplish.

The biggest Draw back is That it takes 12 or more hours to transcode an MKV to MP4 in VisualHub. If any one knows an eisier and FASTER! way to do this please reply!
Also is there a way to do the same with the video in quicktime pro?
What I mean is:
-1. open the MKV file in in quicktime Pro
-2. Extract the AAC audio stream.
-3. Convert the AAC audio to AC3 with Graphedit
-4. Past the AC3 file
-5. Save as .MOV file

I think I will try this. If it works I think this will the fastest way thus far to Transcode MKV with AAC to Apple TV with AC3 passthrough.

[wiz561]

I was wondering if anybody has a ffmpeg or mencoder command that can be used in terminal. It would be great to have a script to do this.