TS to MPEG and Editing ... Probably "noobie" questions

J

jonmitch

New Member
Hello Everyone,

Having bought a Humax HDR Fox T2 at the weekend (and am extremely pleased with it), I have what are probably a few "noobie" questions. I apologise if it is bad etiquette to ask such questions as a first post.

I have installed the "custom firmware" in order to be able to decrypt and transfer recordings from the Humax. This seems to be working fine (though I am having a few browser issues with the "download" command on the web interface).

Having transferred the .ts files to my PC, I am trying to extract the MPEG files from the .ts files without transcoding (in order to not lose quality). I am managing to achieve this with Video Redo, but the resultant MPEG file is about 2/3 the size of the .ts file. Checking the video data rate confirms this. Worrying that perhaps this process wasn't actually losslessly extracting the MPEG from the .ts file, I tried something else.

Next I tried downloading the "ffmpeg" package for the Humax Custom Firmware. Extracting the MPEG this way also results in an MPEG file that is around 2/3 the size of the original .ts file.

So, I'm beginning to wonder if perhaps this is normal. Is there so much extraneous data in the .ts file that makes the video bit rate so much bigger than the extracted MPEG file ? I had expected a little smaller file - but 2/3 is a lot smaller.

Can anyone advise if this is normal, and quell my fears that I am not actually losslessly extracting the MPEG from the .ts file ? Also, can anyone advise any alternative workflows I should consider ?

Finally, a couple of other questions that I am playing with at the moment :

1) I have recorded a film from an HD preview channel. It is a .ts file on the Humax. I have the option of extracting the MPEG from the web interface, but I thought the Freeview HD channels transport streams weren't based on MPEG ? Should I be extracting another type of file from the HD .ts files ?

2) MPEG Streamclip (on the Mac). I was hoping to use this to trim start, end, & adverts (where appropriate) - but I can't get it to open the .ts files from the Humax (yes - they have been decrypted), and although it opens the MPEG files from the Humax and I get audio, the video is a white screen. Does anyone have any experience of using MPEG Streamclip with Humax files ?

Thanks for any help and advice anyone can offer.

Jon
 
Slight update to the above. I'm not sure the MPEG extraction from the web interface is working properly. First one went OK, on a 40-minute program. Tried it on a few longer files (films - around 2 hours) and they didn't work so well. They won't play back on the Humax without stuttering, and navigating to "media" directories on the Humax (from the remote, not the web interface) is painfully slow - lots of "processing" messages on screen.

I'm sure I'm just doing something wrong, but would welcome some thoughts from anyone who is doing what I am trying to do.

Thanks,

Jon
 
jonmitch said:
So, I'm beginning to wonder if perhaps this is normal. Is there so much extraneous data in the .ts file that makes the video bit rate so much bigger than the extracted MPEG file ? I had expected a little smaller file - but 2/3 is a lot smaller.
Click to expand...
Yes, it's normal.
2) MPEG Streamclip (on the Mac). I was hoping to use this to trim start, end, & adverts (where appropriate) - but I can't get it to open the .ts files from the Humax (yes - they have been decrypted), and although it opens the MPEG files from the Humax and I get audio, the video is a white screen. Does anyone have any experience of using MPEG Streamclip with Humax files ?
Click to expand...

I had a similar lack of success with it on a PC. Seems to be a pile of ****.
 
First, I'm not sure MPG conversion works on HiDef recordings. You need to decrypt them first in any case (details on the Wiki).

For decrypted StDef, the MPG conversion is only a repackaging exercise. Extraneous data is removed from the broadcast transport stream and the video/audio streams are repackaged into an MPG wrapper, so no there is no loss of "useful" data.
 
jonmitch said:
Can anyone advise if this is normal, and quell my fears that I am not actually losslessly extracting the MPEG from the .ts file ?
Click to expand...

It's normal. There is a lot of overhead in the raw broadcast stream (which is pretty much what ends up in a .ts file, albeit filtered by Programme ID). For a start, a .ts file is broken into packets, each of 192 bytes, and each packet has a header. Then there are a number of tables in the stream like the Network Information Table (NIT), Programme Allocation Table (PAT) and biggest of all is the Event Information Table (EIT) - basically EPG data which can be up to 300MB/hour of broadcast. The EIT data is what the shrink process removes. Nowadays there's also usually an audio description audio stream too.

Extracting a HD recording to MPG doesn't produce anything useful. The web interface should really grey out that option.
 
jonmitch said:
Hello Everyone,

2) MPEG Streamclip (on the Mac). I was hoping to use this to trim start, end, & adverts (where appropriate) - but I can't get it to open the .ts files from the Humax (yes - they have been decrypted), and although it opens the MPEG files from the Humax and I get audio, the video is a white screen. Does anyone have any experience of using MPEG Streamclip with Humax files ?

Thanks for any help and advice anyone can offer.

Jon
Click to expand...

MPEG Streamclip worked fine with transferred files from my old Humax (9200). But files transferred from the Fox T2 won't open properly, they give a white screen. I don't know what the difference is. I found that passing the files through VLC first (I forget the actual setting as I haven't done it for a long time, but it ran fairly fast) provided a file that Streamclip could recognisee and process. I think there may have been some differences between VLC 1 (which I used) and VLC 2.
 
af123 said:
It's normal. There is a lot of overhead in the raw broadcast stream (which is pretty much what ends up in a .ts file, albeit filtered by Programme ID). For a start, a .ts file is broken into packets, each of 192 bytes, and each packet has a header. Then there are a number of tables in the stream like the Network Information Table (NIT), Programme Allocation Table (PAT) and biggest of all is the Event Information Table (EIT) - basically EPG data which can be up to 300MB/hour of broadcast. The EIT data is what the shrink process removes. Nowadays there's also usually an audio description audio stream too.

Extracting a HD recording to MPG doesn't produce anything useful. The web interface should really grey out that option.
Click to expand...


Thanks for the info. Does the same apply to extracting MPG from DVD .vob files ? I have a bunch of my DVDs stored as ISOs on my network for my old XBMC to read. Unfortunately neither my TV, BluRay, or my new Humax will read them. When I tried to extract the MPG from them losslessly (I think I tried MPEG Streamclip and also vob2mpeg, but it was a while ago) I assumed I was doing something wrong as, again, the .mpg file was significantly smaller than the original .vob. It could be that I was actually doing it fine, but didn't realise there would be such a drop in file size & data rate.

Thanks again,

Jon
 
Are you trying to extract mpg from iso??

An "iso" is an image file of a complete DVD, which you can use with a burner program to burn an exact copy of the DVD. What you would need to do to extract the video information from it is to actually burn a DVD (or mount it as a virtual DVD drive), then extract the mpg data from the vob files within. Think of the iso as being like a zip - first you need to unzip, and then you can use the unzipped data.
 
jonmitch said:
Thanks for the info. Does the same apply to extracting MPG from DVD .vob files ? I have a bunch of my DVDs stored as ISOs on my network for my old XBMC to read. Unfortunately neither my TV, BluRay, or my new Humax will read them. When I tried to extract the MPG from them losslessly (I think I tried MPEG Streamclip and also vob2mpeg, but it was a while ago) I assumed I was doing something wrong as, again, the .mpg file was significantly smaller than the original .vob. It could be that I was actually doing it fine, but didn't realise there would be such a drop in file size & data rate.

Thanks again,

Jon
Click to expand...

Mount the iso as a virtual DVD drive (As Black Hole suggests), I use

http://www.slysoft.com/en/virtual-clonedrive.html

Explore the virtual drive using explorer and copy the vob's to a normal drive. Extract the mpeg2 in any way you're familiar with. I would simply add the first to tsmuxergui and join the rest and mux to a transport stream file (.ts).
 
Hi Black Hole & Graham,

Thanks for the responses. My workflow (from memory) was to use DVD Shrink to open the ISO file, then save as a VIDEO_TS folder. Then join the relevant .vob files from within the VIDEO_TS folder using Simple File Joiner (very useful bit of freeware). This bit I was comfortable with (though just opening the ISO as a virtual drive would probably be easier !). The bit I was getting stuck on was when I then tried to extract the .mpg files from the .vob files, losslessly, I was getting a significantly smaller .mpg file. I was expecting about the same size, but wondered if the same reasoning as applied to extracting .mpg from .ts files from the Humax was also valid for extracting .mpg files from .vob files - is there that much extraneous information in the .vob files that gets removed when (losslessly) unwrapping to a .mpg file ?

Thanks,

Jon
 
Fair enough, we can only answer what we read.

I think the conversion from vob to mpg is easier than that. I know you can just join the vob's together (they are split up to avoid file size restrictions in old operating systems), but I think if you just rename the file .mpg instead of .vob it will work. Try it on one vob before you join them.

What are you using to extract the mpg? I think VLC will do it (select "convert").
 
jonmitch said:
The bit I was getting stuck on was when I then tried to extract the .mpg files from the .vob files, losslessly,
Click to expand...

You probably don't need to extract to mpg, the vob format is already in meg2 format just re-name the file from vob to mpg
 
Hi everyone,

Thanks for the suggestions. I tried the renaming trick and it did work. Only thing that didn't seem to work was the aspect ratio flag wasn't right, but otherwise the video & audio were good. Now I'm on the prowl for a way to edit the AR flag in the MPEG file header ...

Anyway, my previous attempts at extracting MPEG from VOB were using MPEG StreamClip, Womble MPEG Video Wizard, and vob2mpeg.

Lots more testing and experimenting to do. Just found that Womble MPEG Video Wizard opens the .ts files from the Humax directly (didn't expect that), but unfortunately the resultant MPEG doesn't have audio when played back on my old XBox running XBMC. Strange, as the same file plays fine on WMP, and when running XBMC on my mac mini. Redid the experiment making the PIDs the same as for VideoRedo and still no audio. something odd going on there.

Oh well, all good fun experimenting, but time for bed. Thanks for the help so far everyone - I really am enjoying learning so much about this.

Jon
 
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