Creative Communities of the World Forums

The peer to peer support community for media production professionals.

Activity Forums Apple Final Cut Pro Legacy Muxing with MPEG Streamclip: quality loss?

  • Muxing with MPEG Streamclip: quality loss?

    Posted by Paulo Jan on May 7, 2007 at 9:12 am

    Hi all:

    In order to create MPEG2 clips in just one file (.mpg), we’re using Compressor to create a .m2v and a .aiff file, and then using MPEG Streamclip to mux them in just one MPG. It works fine, but my boss suspects that there might be quality loss this way, and keeps asking me if there’s any way to export a MPEG2 .mpg directly from FCP’s timeline using Quicktime (I know there isn’t, starting with FCP5), or if Compressor can do it (from what I’ve seen, it always creates the .m2v and the sound file separately).

    As for MPEG Streamclip, I’m pretty sure that muxing shouldn’t cause any quality loss, because you’re not recompressing-reencoding any video, just putting two streams together (the only quality loss would be in the sound, when encoding to MP2), but just to be absolutely completely super-duper 100% sure and be able to tell so to my boss: muxing shouldn’t degrade image quality, should it?

    Paulo.

    Rafael Amador replied 17 years, 9 months ago 8 Members · 11 Replies
  • 11 Replies
  • Ben Holmes

    May 7, 2007 at 9:52 am

    Paulo

    Just a query – why do you need to create audio/video MPEG 2 files? Seperate files are better for DVD creation (supporting multiple audio tracks in the DVD project) and MPEG2 sucks for most other things anyway – it’s a pretty noisy delivery codec.

    Just wondered, as it may be that you could deliver in a more suitable and FCP friendly format.

    Ben

    Editec Broadcast Editing Ltd

    EVS & FCP specialists for live broadcast.

    OB Server 1 HD – Mobile FCP editing done right.

  • Paulo Jan

    May 7, 2007 at 10:02 am

    It’s for a TV station that we’re working with. From what I understand, they have one of those broadcast server things that use .mpg files, and have asked us to deliver in this format. I did a search here a few weeks ago, and it looked like we weren’t the only ones; there were more people asking about outputting .mpg files, and for the same reason.

  • Ben Holmes

    May 7, 2007 at 10:17 am

    OK.

    I assume you’ve tried a split screen comparison between the muxed and unmuxed video? I don’t think the muxing process should alter the video file in any way, so it may just be that your boss has an unrealistic expectation of how good MPEG2 will look – it’s pretty lossy for video.

    Sorry I can’t be of any other help.

    Ben

    Editec Broadcast Editing Ltd

    EVS & FCP specialists for live broadcast.

    OB Server 1 HD – Mobile FCP editing done right.

  • Tom Matthies

    May 7, 2007 at 1:37 pm

    We are having the same issues with the delivery of our local spots. Although (for now) TV stations in our area are still taking tapes, the Time Warner systems are all now requesting .mpg files for their servers. It’s become somewhat of a pain in the patootie for everyone here. The Avid Symphonys can’t do it and the FCP systems can but it’s a pain to loose all that quality. And then there is the time it takes to send the files (right now they are all Quicktimes) to them via their FTP site…which keeps changing locations as well as they cut back and consolidate resources.
    Is there a way to mux the video and audio streams right within Compressor?
    Inquiring minds want to know.
    Tom

  • Paulo Jan

    May 7, 2007 at 2:33 pm

    [Tom Matthies] ” and the FCP systems can but it’s a pain to loose all that quality”

    Ah, but here’s the thing. Does it *actually* lose quality? Because, in a side-by-side comparison between the original .m2v and the .mpg, I honestly can’t tell the difference. My impression is that my boss simply had never heard about MPEG Streamclip before and that’s why he distrusted it.

    (As for the general point of broadcast stations broadcasting in MPEG2 instead of, say, Betacam… hell, even satellite TV (DVB) uses MPEG-2 now, doesn’t it?).

  • John Pale

    May 7, 2007 at 3:01 pm

    There is no loss in video quality during the muxing process. The video track is simply copied…its not re-encoded.

    You can produce a muxed file directly in Compressor.

    In the Inspector, in the Extras Tab (with your MPEG-2 Preset selected) select Multiplexed MPEG-1 Layer2 audio (creates an MPEG-2 Transport Stream with multiplexed audio). Note the audio is encoded to MPEG, so there can be small quality loss there, but thats what the format requires.

    I have also used an app called Bitvice Helper to produce Muxed MPEG-2’s.

  • Ken Doll

    May 7, 2007 at 3:05 pm

    This was mentioned in a previous post. I have to encode .mpg’s for our Nexus media server. It is possible to create muxed files in Compressor but you have to do a quick file conversion in MPEG Streamclip to get a .mpg file.

    Open Compressor and select and set up for MPEG2 Encoding. In the Inspector click on the Encoder tab (2nd from left) and you’ll see Video Format, Quality, GOP, Extras. Go to Extras and select Multiplexed MPEG-1/Layer 2 Audio. That’ll give you an MPEG-2 Transport stream with mlutiplexed audio. This encoding will take the normal time as if encoding for a DVD. I take this file and drag it into MPEG Streamclip. It is a very quick file conversion and the audio will take a slight volume hit. File-export with MpegwithMP2 Audio. After exporting the file, the extension will end with .mpeg – delete the e so that the extension is .mpg

    Ken

  • Tom Matthies

    May 7, 2007 at 3:23 pm

    Actually I was referring to the loss of quality when going from an 8-bit UC timeline in FCP down to an .mpg file for use by the cable company.
    Yuk!
    Tom

  • Mike Weber

    May 7, 2007 at 3:57 pm

    >>You can produce a muxed file directly in Compressor.
    >>In the Inspector, in the Extras Tab (with your MPEG-2 Preset selected) select Multiplexed MPEG-1 Layer2 audio (creates an MPEG-2 Transport Stream with multiplexed audio). Note the audio is encoded to MPEG, so there can be small quality loss there, but thats what the format requires.

    A word of caution on this – some on-air systems with older decoder cards (like the one at our station) cannot play back a muxed Trasnport Stream file, only Program Stream.

    The good news: With the new version of Compressor coming this month, you will be able to make both a muxed Transport or Program stream MPEG-2 file, eliminating the need for MPEG Streamclip altogether.

  • Michael Alberts

    May 7, 2007 at 9:45 pm

    We use the same method as Ken for our Pathfire uploads. They also require us to upload MPEG1 files which we’re forced to use Cleaner for. Compressor can’t meet the specs for the MPEG1 specifics.
    We’re probably going to take Telestrem up on their offer to trade in our copy of Cleaner to Episode Pro for $500.

    Michael Alberts
    Ambidextrous Productions, Inc.

Page 1 of 2

We use anonymous cookies to give you the best experience we can.
Our Privacy policy | GDPR Policy