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H264 transport stream with AC3?

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Steve Ulrich
H264 transport stream with AC3?
on Aug 9, 2013 at 1:37:21 pm

I'm not an encoding expert, but generally I can deliver pretty much anything that a client wants in terms of formats. But this has me a little baffled and I was wondering if anyone could chime in with some insight.

Client wants:
H264 1080p 23.98
H264 Video Size - Min 30Mbps CBR
MPEG2 Transport Stream 35 Mbps (CBR transport stream)
File Extension - .TS
H264 Profile - Main or High
H264 Level: 4.1
GOP - Long GOP (GOP size = 24 or 12, P frame distance = 3)
Chroma Subsampling 4:2:0 or 4:2:2
Audio - AC-3 Dolby Digital audio; stereo or surround sound

...etc, etc, etc.

To me some of this seems contradictory... For example, an MPEG-2 transport stream and H264? Is this even possible? Or does this sounds like two different options? A .TS container?

If this is possible, what on earth would I use to encode and package all this up? I have the Adobe cS6 Suite, MPEG Streamclip, Squeeze v8.0. The only thing I found to wrap things up into a TS file was VLC. But it would only let me do that if I transcoded to MPEG-2 on exporting. Obviously VLC is not the ideal muxer anyways.

Anyone have any ideas? Any help or insight much appreciated.
Steve


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Craig Seeman
Re: H264 transport stream with AC3?
on Aug 9, 2013 at 2:53:31 pm

H.264 in MPEG2 TS is certainly possible.
Telestream Episode Pro or Engine can do this.
Download the free trial and test.



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Steve Ulrich
Re: H264 transport stream with AC3?
on Aug 10, 2013 at 9:29:36 am

Thanks very much Craig, for your suggestion. I'll have a look at the Episode trial. I've used it before. Pro version is 1200 bucks though - ouch.

I'm definitely going to have to look into these types of formats though. I still don't really understand what's going here. With MPEG-2 and H.264 in the same file with 2 different bitrates.

Can anyone tell me what these formats are usually used for? Who wants a .TS file and why would you want it? I'm only delivering a 2 minute video for a website, so this seems extremely complicated for this type of usage. But perhaps it is a good as a sort of master file for archival purposes. In any case, the file I'm delivering is going to have to be transcoded for the web, for obvious size and data rate issues - which makes me wonder why they're asking for it in the first place.

Thanks Craig for your answer and to anyone else who may want to share some experience with this sort of thing.

Steve


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Craig Seeman
Re: H264 transport stream with AC3?
on Aug 10, 2013 at 3:32:19 pm

[Steve Ulrich] "'m definitely going to have to look into these types of formats though. I still don't really understand what's going here. With MPEG-2 and H.264 in the same file with 2 different bitrates."

MPEG2 TS is the container format.
Don't confuse containers with codecs. Just as .mp4 can contain MPEG2 or H.264 amongst other thing. for example.

Transport streams are used for reliable broadcast delivery
Read about the use of Transport Streams in Wikipedia
http://en.wikipedia.org/wiki/MPEG_transport_stream

Also used in HTTP Live Streaming (aka HLS).
http://en.wikipedia.org/wiki/HTTP_Live_Streaming

Perhaps this is their intended use if it's web delivery.

Squeeze can do this since version 7 from what I understand.
Episode can do this as well.



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Steve Ulrich
Re: H264 transport stream with AC3?
on Aug 10, 2013 at 5:47:37 pm

Thanks again Craig. I do get that the MPEG TS is the container and H264 the codec - just throws me a little that they are asking for an MPEG TS @ 35Mbps and H.264 Video Size of 30Mbps. If the codec sits inside the container, that means there's 5Mbps of other stuff floating around in there which I don't really get - seeing how the audio wouldn't make that up.

I read the Wikipedia link and it makes sense to me that a transport stream is used for unreliable transmission of video data via packets with adequate error correction. Also makes sense to use something like that for internet streaming - for the same reasons. It's just that this video will for sure be reduced vastly in size and quality and played in a little box in the middle of a webpage - so it seemed to me to be an odd and very specific format to ask for if it was to be reduced and reconverted again later. Then again, why not...

I also finally found how to wrap H264 up in a transport stream in Squeeze - one has to pick either "Digital Signage" or "AVCHD" as the format constraints in an MPEG preset. But this saves a file with an mpg extension. Don't know if you can just rename it or not.

In any case, thanks for your insight. I'm going to try to read up a bit more on this and see if I can't come out of it a little bit smarter.


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Craig Seeman
Re: H264 transport stream with AC3?
on Aug 10, 2013 at 6:09:01 pm

[Steve Ulrich] "ust throws me a little that they are asking for an MPEG TS @ 35Mbps and H.264 Video Size of 30Mbps. If the codec sits inside the container, that means there's 5Mbps of other stuff floating around in there which I don't really get "

Transport streams can have overhead. Episode allows this kind of setting.

[Steve Ulrich] "It's just that this video will for sure be reduced vastly in size and quality and played in a little box in the middle of a webpage"

Based on what? You haven't provided any information that would indicate and certainly the settings don't.

[Steve Ulrich] "But this saves a file with an mpg extension. Don't know if you can just rename it or not. "

I believe some programs do that. Do make sure you're making a Transport and not a Program stream. If Squeeze uses .mpg you may need to experiment by sending the encode to the client. You could send both .mpg and renamed as .ts and ask if either or both work.



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Steve Ulrich
Re: H264 transport stream with AC3?
on Aug 11, 2013 at 10:22:59 am

[Craig Seeman] "Transport streams can have overhead. Episode allows this kind of setting."

Interesting...

[Craig Seeman] "Based on what? You haven't provided any information that would indicate and certainly the settings don't."

Just based on what they usually do with these videos - and based on the music licensing that they are purchasing. Of course they might want to do something else with it later. I agree that the settings don't indicate this. All part of my confusion.

[Craig Seeman] "I believe some programs do that. Do make sure you're making a Transport and not a Program stream. If Squeeze uses .mpg you may need to experiment by sending the encode to the client. You could send both .mpg and renamed as .ts and ask if either or both work."

Yup, definitely a transport stream. Episode sounds like it's a lot more flexible than Squeeze. Might be worth the investment to switch over. At least I know I'll never run into anything I can't do anymore. I'll try what you suggest concerning the extensions and post back with the results.. Appreciate greatly all of your valuable input Craig.


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