Surround Sound loses channels on copying to PC

[Kevin]

Hi folks, I am trying to copy a film, recorded from BBC1 HD and decrypted by custom firmwear, to my PC, to trim with Video Redo and archive. The film (decrypted file) plays in full surround sound from the Hummy, but Video Redo tells me that the file I have copied off only has 2 channel audio. Sure enough, if I rename the file and copy it back to the Hummy, my rear channels have disappeared. Can anybody tell me whether it is possible to copy files from the Hummy, preserving all 6 audio channels? Many thanks.

 

[Black Hole]

Can anybody tell me whether it is possible to copy files from the Hummy, preserving all 6 audio channels?

By what mechanism did you copy it?

If it plays in surround, then the surround sound must be in the .TS file - it can't be anywhere else. You can prove nothing has happened in the process of copying the file off the HDR-FOX by putting it back (without editing it) and then after you edit it.

Update

The subsequent discussion reveals that multi-channel audio playback on the HDR-FOX is contingent on a previously unknown flag in the .hmt sidecar file, and without this present (eg in a missing .hmt, or a reconstructed .hmt) playback reverts to stereo. Nonetheless, the AAC audio stream remains intact in the M2TS (Humax .TS file)*, and if it doesn't play as multi-channel in an external media player then either the player/editor isn't multi-channel capable, or the audio stream is only stereo in the first place.

* HDR-FOX recordings are in M2TS container format, albeit that the filename has a .TS extension. External players may or may not auto-detect, but if a file won't play externally: first ensure the file has been decrypted (see Things Every... Section 5); and secondly try renaming the file to .M2TS. If editing a recording to reimport into the HDR-FOX for playback, either save as .MP4, or save as .M2TS and then rename it to .TS. As .TS, it is then possible to generate sidecar files so that it plays as if a native recording (multi-channel audio flag notwithstanding).

 

[Kevin]

I copied the file to the PC via ethernet, using FileZilla. The process I always use, but I have never knowingly copied a file with surround sound before.

Yes the decrypted file definitely has full surround sound, but the rear channels disappear after copying to the PC and back without editing.

 

[Black Hole]

I copied the file to the PC via ethernet, using FileZilla.

OK, by FTP then. That's safe.

the rear channels disappear after copying to the PC and back without editing.

There must be something else going on.

 

[Luke]

There must be something else going on.

From the description the recording has been copied back as a single "file". Playing the TS file on the Humax without the sidecar files, and the Humax will then use a different mechanism to play back and that mechanism plays back in stereo.

Video Redo tells me that the file I have copied off only has 2 channel audio.

I suspect it has both 2 channel and 5.1, but the 2 channel is taking precedence.
You'll be able to check that using medainfo.
Years ago I believe there was someone having a similar issue on this site but I can't find the thread.

 

[Black Hole]

Playing the TS file on the Humax without the sidecar files, and the Humax will then use a different mechanism to play back and that mechanism plays back in stereo.

I agree that might well be the source of the problem, but I don't understand how. An AAC audio track is an AAC audio track, is it not? I don't think there are separate streams to choose from.

 

[Kevin]

Thank you both very much for your input. I had not considered the effect of the sidecar files. Today I have tried the following:

1) Copy to a USB HDD using Hummy's copy function - file plays with surround sound.
1a) Remove the sidecar files to a different folder (using FileZilla) - file plays in stereo.
1b) Replace the sidecar files - plays in surround sound again.

2) Copy the .ts along with its sidecar files to the PC, using FileZilla, then copy them all back to a new folder on the Hummy HDD - file plays in surround sound.
2a) Move the .hmt file to another folder - plays in stereo.
2b) Replace the .hmt file - plays in surround sound again!

So, yes, there must be something in the .hmt file which tells the Hummy to play surround sound, else it defaults to stereo.

I am confused why VideoRedo says the file has 2 channel audio? Perhaps the intro frames before the film starts are only stereo and this is what VideoRedo is reading out?

With your help, I have learned a lot, but am still no nearer my original objective of creating an edited file, from VideoRedo, retaining Surround Sound.

I believe that I now understand the process of setting VideoRedo up to output 5.1 channels, but it seems that this is no use unless I can somehow generate a suitable .hmt file to tell Hummy to play all the channels...

 

[Luke]

I am confused why VideoRedo says the file has 2 channel audio? Perhaps the intro frames before the film starts are only stereo and this is what VideoRedo is reading out?

Possibly, as that has been reported with another tool, not VideoRedo, I think it was a player.
On that occasion cropping the start on the Humax and re-exporting and the player recognised the surround sound

 

[prpr]

I believe that I now understand the process of setting VideoRedo up to output 5.1 channels, but it seems that this is no use unless I can somehow generate a suitable .hmt file to tell Hummy to play all the channels...

If you're editing the .ts file externally, then you'll need to regenerate both the .nts and the .hmt files. Have you looked at the sidecar package?

 

[Kevin]

Thanks for your suggestion. I have installed the sidecar package, but it gives me: "ERROR: Source video packet size is 188 bytes, must be 192."

 

[Kevin]

The sidecar package does generate sidecar files for the unedited ts file, and this then plays with surround sound
Question is why the video packet size is wrong on the file I have edited in VideoRedo?

 

[Luke]

Question is why the video packet size is wrong on the file I have edited in VideoRedo?

All recordings made on T2 have 192 byte packet size. Export from Video redo should be set to M2TS to recreate 192 byte packet format.

For those that you have already edited:

I open the files in VideoReDo then save them as .m2ts files, (MPEG2 M2TS (*.m2ts) on the Save As menu, then rename the .m2ts to .ts. I'm not sure whether any remuxing is involved but the process is very quick and the VideoReDo displays that it is doing "Fast Frame Copying". Raydon's sidecar package can then use these files to create the sidecar files and they play fine on the Humax.

 

[Kevin]

Thanks, Luke. I had already made an m2ts file in VideoRedo, but it did not appear on Hummy's list. I have now renamed this to .ts and it now appears. Sidecar package has generated new sidecar files for it, but no surround sound

 

[Kevin]

After reading some other threads, I have tried outputting as MKV. Still no surround sound :|

 

[MontysEvilTwin]

Have you tried analyzing the recordings (original and edited) with ffprobe? If you have ffmpeg installed on your HDR-FOX you can use the following from the command line:

ffprobe -i "Recording Name.ts"

This will tell you exactly which streams are available in each file.

EDIT. To add, first copy the recordings to the "My Video" folder then use the following command to navigate to this directory:

cd "/media/My Video"

 

[Black Hole]

Have you looked at the sidecar package?

That's all very well (and it should be well known by now to export from editors as M2TS and then rename to TS if necessary), but does sidecar recognise a multi-channel stream and set the appropriate flags in the .hmt (rhetorical, because I don't think we have the source)?

Maybe it can be adjusted after being generated using the hmt utility, but I had a glance through the definition and didn't spot anything about multi-channel audio.

 

[prpr]

does sidecar recognise a multi-channel stream

That was the question I wanted answered.

and set the appropriate flags in the .hmt

Clearly it doesn't, given the subsequent information.

(rhetorical, because I don't think we have the source)?

We don't.

Maybe it can be adjusted after being generated using the hmt utility,

Naturally.

but I had a glance through the definition and didn't spot anything about multi-channel audio.

It doesn't ring any bells with me either. We'd need a copy of the original .hmt file if @Kevin could oblige.

 

[MontysEvilTwin]

If it helps I have a couple of episodes of Doctor Who with 5.1 audio:

Stream #0:0[0x19c9]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc                                                                            
Stream #0:1[0x19ca](eng): Audio: aac_latm (LC) ([17][0][0][0] / 0x0011), 48000 Hz, 5.1, fltp                                                                
Stream #0:2[0x19ce](eng): Audio: aac_latm (HE-AACv2) ([17][0][0][0] / 0x0011), 48000 Hz, stereo, fltp (visual impaired) (descriptions) (dependent)          
Stream #0:3[0x19cd](eng): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)    
Stream #0:4[0x19fa]: Unknown: none ([5][0][0][0] / 0x0005)                  
Stream #0:5[0x19d2]: Unknown: none ([11][0][0][0] / 0x000B)                
Stream #0:6[0x1c86]: Unknown: none ([11][0][0][0] / 0x000B)

I have also attached the original hmt file and a Sidecar-generated hmt file.

 

[prpr]

If it helps I have a couple of episodes of Doctor Who with 5.1 audio

Thanks. Nothing of interest discovered. Can you confirm the OP's findings?

 

[xyz321]

I don't seem to be able to find any 5.1 source for testing but perhaps 0x73a is the most promising...

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