AAC-HE LATM Support again

[lchiu7]

chris57 Wrote:For Syabas you are talking long term if it is possible and also a popular request.

I tried using transportstream and mkvmerge to get to an mkv from those TS streams, normally its not a problem, and it wouldnt play ball. Cant remember the error message.

The audioconverter uses FAAD and Aften on AAC audio to convert to AC3 via WAV. Works on AAC-LC-SBR and may work on AAC-HE. If not then it also has Nero AAC encoders/decoders which may be another alternative.

I finally found a way to convert those streams to play on the PCH. It's fairly messy but involves

1. demuxing with dgavcindex (the author updated the tool to handle these streams)
2. Playing the aac file in Winamp and outputting a wav file (this was the main breakthrough)
3. Converting the wav file to ac3 using besweet
4 Muxing back with tsmuxer to a ts file (the avc file and ac3 file)

The resultant file plays fine on the PCH with no video quality loss. Have to watch av sync but a few tests should solve that.

So it helps but of course means watching can't be done in real time.

[emveepee]

If only getting the audio is what you want, mplayer nightlies for months let in do this (the first file even plays on the pch with sync issues)

mencoder infile.ts -ovc copy -ffourcc h264 -oac pcm -o outfile.avi

Afters just use ffmpeg to get the ac3

ffmpeg.exe output.avi -acodec ac3 output.ac3

I don't find the tsmux'd solution any better then the mencoder file either.

Martin

[lchiu7]

emveepee Wrote:If only getting the audio is what you want, mplayer nightlies for months let in do this (the first file even plays on the pch with sync issues)

mencoder infile.ts -ovc copy -ffourcc h264 -oac pcm -o outfile.avi

Afters just use ffmpeg to get the ac3

ffmpeg.exe output.avi -acodec ac3 output.ac3

I don't find the tsmux'd solution any better then the mencoder file either.

Martin

Didn't know that since I don't use that program. Audio/sync is still an issue but solvable.

How do you get the ac3 audio muxed back with the AVC video?

I found that TV1 files shows a constant 1s delay that needs to be incorporated in the mux back. The HD Freeview has no delay (mainly TVNZ) while if you try to mux back AC3 audio demuxed from TV3 transmissions (this is done if you want to recompress the video a bit more), then there is a -1s delay!

All quite annoying.

[emveepee]

I've tried several solutions to mux the streams, including your suggestion with TSMux and I haven't been satisfied with the sync. Note I'm not from NZ and don't have access to samples either, I'm really just paying attention on behalf of a few GBPVR users.

Martin

[lchiu7]

emveepee Wrote:I've tried several solutions to mux the streams, including your suggestion with TSMux and I haven't been satisfied with the sync. Note I'm not from NZ and don't have access to samples either, I'm really just paying attention on behalf of a few GBPVR users.

Martin

As I noted in my earlier thread, I have worked it out. The process I used creates files that are either in sync, or not :-) But they are out of sync by a fixed amount, so far 1000ms or -1000ms. It's trivial to be able to adjust that when muxing them back.

For samples here are some I captured myself the other day

http://www.datamix.info/one%20news%20aac_.edit.ts
http://www.datamix.info/One%20audio.ts

The author dgavcindex used those streams to update his program to handle the AAC-HE LATM streams and now it works as noted.

[lchiu7]

Nothing in the latest firmware. In the next perhaps?

[pdenham]

(08-27-2008 10:25 AM)lchiu7 Wrote:  Nothing in the latest firmware. In the next perhaps?

Yes I second that, we have just had our only other channel playing ac3 drop the audio so we can only watch one channel on our popcorn hour's in New Zealand.

Can anyone confirm it will be in a future firmware please?

[Deev8]

(08-27-2008 10:25 AM)lchiu7 Wrote:  Nothing in the latest firmware. In the next perhaps?

Yes it would be very good to be able to watch New Zealand Freeview HD recordings on the PCH.

[lchiu7]

Syabas: are you listening? Would be nice to know if it's even on the development path for future firmware releases.

Thanks