Getting nowhere converting vid with AAC to AC3

[sTuDeimus]

Hi,

I'be been trying for a week or so now to convert a single file in this manner:
AVC/[AAC+AC3]/MKV => AVC/AC3/ANY
Orig AAC => AC3
Orig AC3 dropped (or retained, I don't care)
Don't care about the target container... have tried MKV/AVI/MP4/TS/(other?)

Problem: I've not been able to have MC do this without reporting creation of a 0MB file, or throwing error15 (muxer error), depending on what profile settings I'm using.

Things I've tried:
- running the profile wizard, selecting AVC/AC3 as default targets, , cpu-only acceleration, and whatever other sttings seemed sensible.
- always set the video profile to copy-video.
- set audio to whatever target format, selecting either of the two audio streams.
- Usually leave the encoder/source on auto. I have tried some specific values for these (eg. ffmpeg, mencoder), but I really don't know which are expected to work so prefer the auto setting.
- I've confirmed that the vid plays fully in the MC player window.
- I have pulled up the console window and can see the particular tool failing, but I'm hoping there is some correction I can make to how I use the tool such that I won't have to fully dive into how the different cmdline conversion tools (do or don't) work.
- for the container, I usually just select one and then use auto-mux, though I have tried some as I did with the auto tab.
Usually I don't touch the other tabs, but occasionally go through looking for tweaks.
- I am able to do the conversion if I select the likes of MP3/vorbis as target audio format
- I've also tried some older versions o MC, but aside from that not making any difference, the list of tests done on each version (on the MC side) doesn't show any aspects of what I'm doing that won't work in these latest versions.
- I believe at one stage I did successfully demux to just an ac3 file, for what thats worth.

Most testing done with vrsion 5172, but have also gon back to particular older versions as suggested on the forums. Machine is Core2duo laptop with 4GB RAM running 32bit Win7Pro.

So, am I meant to be more specific about the encoders/containers to use? Am I meant to be demuxing aswell as muxing? Am I meant to install some other codecs to get the AC3 encoding working? Any help appreciated.

Thanks, Stu.

[meRobs]

Hi, welcome to the forum.

Since AVC is got via H264/x264 on the Video tab, I suggest you try the settings given for MP4 in the Encoding Guide (under Tips & Giides, link below).
First try the settings as is, just as a test, and then change the audio to AC3.
Finally, fiddle with the Resize (maybe put = "original") and Resample, bitrates, etc.
Let us know what happens.
G' luck.

[sTuDeimus]

Thanks for your time merobs...

Adjusting my MC settings as suggested initially worked - produced an MP4 file with AVC/AAC(LC).

If I set the video stream to "copy video" it churns through the file at a sensibly faster speed, but then reports the 0MB file.

If from the originally working MP4 config, I switch from LC-AAC to AC3, and set the encoder to auto, MC reports that either the container cannot encapsulate the audio stream, or is unsupported by the multiplexer.

If I then switch the container to MKV or AVI, MC reports error 15 found during transcoding process (muxer error).

Any ideas from that?

Stu.

[ladycoder]

If you can encode the aac audio to ac3 by itself, I would not bother trying to mux it together with mediacoder.

Try encoding the aac audio separately and multiplexing with mmg from mkvmerge.

De-select the aac and add the new audio. This copies the other desired streams and adds the new ac3 into an mkv container.

[meRobs]

Assuming you want help with the original question (how to use MediaCoder to convert your source file), I will continue.
After all, if the problem is due to a bug in MediaCoder, it would be nice to find it so that it can be fixed.
On the other hand, it may be a fault with your settings; and, again, let's find out.

First of all, realise that not all combinations of tab settings will work.
This is especially true for the "Auto Select" option.
For example, since MPEG2 video normally sits with AC3 in an MPEG2 container, the Muxer (multiplexer) is best set at Disabled!
Trying to put a very new video format (H.264) with the rather-old AC3 won't work with the Muxer disabled.
Nor will they combine with the Muxer set to Auto Select!
Also, check out the Guide: viewtopic.php?f=17&t=10885.

I just tried with Multiplexer set at MEncoder or FFmpeg and the combo H.264/AC3/MP4 worked. (FFmpeg encoder for AC3)
Since you stated you didn't care what container is used, this may be your answer !
(I still wonder why you must have AC3)
Of course, you may have a problem if you wish to Copy over the original AVC (H.264) to your choice of container.
The Copy function sometimes gives a problem. If it fails for your combo, the quick answer would be to convert AVC to AVC with a slightly higher bitrate than the original.

The only problem with MediaCoder is that it is capable of doing a vast number of permutations and combinations.
Don't give up on it for this reason.
Suggest you don't demux your source file into its streams, convert (or not) each file, then, mux them back into your choice of container (too many steps with too many Apps).

[ladycoder]

2 steps, 2 apps:

Encode the audio only - AAC to AC3 with MC - I assume it picks the first audio by default.
Load original file and new audio in Mkvmerge, deselect the AAC, move new audio up as default and merge.

[sTuDeimus]

ladycoder... thanks for the suggestion, but I really do want to do without intermediate files if possible. MC looks like a way to do this, so for now I'll persist with it

merobs... thanks for your detailed explanation. Unfortunately, my MC installation still gives me the error15 after the conversion if I convert to H.264 (mencoder/ffmpeg encorder), AC3 (ffmpeg encoder), and MP4 (ffmpeg mux).

I expect that even if that worked, I'd still get the error when trying to switch to copy the vid stream rather than convert.

I'm now wondering if this problem en exists for other files - despite the fact that MC's video player shows it without problem.

Methinks it would be very useful for MC to either forcefully or optionally block the incompatible combinations of options...

As for AC3, I just prefer that as (what I see as) a generic multi-channel format that should play anywhere - plenty of other newer formats, but how well are they supported on different media players?

Stu.

[meRobs]

Does the full conversion fail with Muxer set on Auto?
Copy video does work for most builds when converting a VOB to MPEG2 (container), as indicated in the Test Report (see Tips & Guides - link below), especially because the video in a VOB file is by definition compatible with an MPEG2. I would have thought your AVC would be compatible with MP4.

Maybe, the problem is the AC3? Does the conversion work with and without video copy for other than AC3?

Could you upload a small (1 minute) sample from your source file to a hosting site so that we could experiment with it?
You are being very patient and loyal to MC, so I feel you should be rewarded with some effort from the rest of us.

[sTuDeimus]

Well, I'm a tad embarrassed to say that I just managed to do exactly as I've wanted with 3 other files...

So yes, maybe there is something borked or incompatible with that original test file I was using...

Thanks muchly for your help, and once I find/confirm MC working as required, I'll donate some $$ to the cause.

Stu.