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Transcoding and release thoughts for huge bitrate avchd
  • What are people using for output with, for example, the 176mb mts file.
    Say in adobe, right now, I'm putting the clips in a 108024p avchd sequence file. Is this my best choice?

    Then through media encoder I output the edited file to say, h264 with maxiumn render quality.
    I up the bitrate(though I'm unsure this actually does much) a little to say, avg 40mb/ max 50mb.

    The final files look great, but I have to wonder, since the orginal file is beyond avchd spec at 176mb,
    is there a better way with adobe cs 5.5 to retain better quality? It definitely holds up to grading way better
    than the stock camera settings.
  • 36 Replies sorted by
  • Well Blueray is spec'ed as 54.0Mbps, with - IIRC - a variable that GOP that's usually around 10? Rendering is a non-realtime encode so it can make more efficient use of the bitrate. I used a similar encoding for a short film that was shown at a local cinema last week (part of the 48 Hour Film Project) and it looked good to my amateur (but slowing improving ;) eye.

    I'm curious what the low-GOP lovers on this forum think of the motion rendering of Blueray?
  • @sam_stickland
    While the Blu-ray spec's maximum data transfer rate is 54Mbps, video bitrate is limited to only 40Mbps. Maximum GOP-size is normally one second, i.e. 30 frames for telecined movies. However, scene detection is used to dynamically insert key frames as needed. As you point out, Blu-rays are mastered with non-real-time multi-pass encoders, and produce far more efficiently compressed files than a camcorder encoder can record in real time.

    The bundled H.264 encoder in Adobe CS5.5 does not use B-frames and is thus not very efficient. If you want to maintain the quality of a 176Mbps intra-frame video, transcoding to DNxHD (free download from Avid) or CineForm are probably your best options, unless you have a Mac and want to use ProRes. To produce high-profile H.264 transcodes with CS5.5, you need a licensed plugin like MainConcept Codec Suite 5.1, or alternatively you could process the MTS files externally with the x264 encoder.
  • @LPowell
    "If you want to maintain the quality of a 176Mbps intra-frame video, transcoding to ..."
    You wrote that the CS5.5 does not use B-frames but 176Mbits Drifwood not use the B-frames so whether it makes sense to transcode to another format? I am not a professional so do not be upset this question
  • @Mihuel
    The value in transcoding Driftwood's 176Mbps intra-frame patch to H.264 would be to lower its huge bitrate without degrading its image quality. CS5.5's bundled H.264 encoder isn't a good choice because, without B-frames, it cannot produce efficiently encoded AVC files. It's similar to the GH1's AVCHD encoder, which also lacks B-frames, and needs 75+ Mbps to produce its highest image quality. The GH2's B-frames enable it to produce comparable image quality at rates as low as 44Mbps.
  • @LPowell
    So, even at 176Mbits Driftwood Intra, in CS5.5 better to transcode to another codec Intra (DNxHD or Cineform) because Premiere does not deal with the correct (best) decoding AVCHD? (And I do not mean the difference between 8bits color and 10 bits...)?
  • @Mihuel
    While Premiere CS5.5 will decode it properly, the high AVCHD bitrate will become a performance issue once you start laying effects on the timeline. Using a faster codec and/or lower bitrate will make it more responsive. Using proxies to substitute for the 176Mbps clips is another effective option.
  • Thank you for your sensible answer. It gives me much to think about. I have read more about proxies to make life easier :-)
    P.S. Premiere is not Cubase or ProTools and I have to learn , learn ....
  • So you're saying the value of transcoding to h264 before editing in premeire is just that it is a more efficent codec to work with. That is, there will be no difference in the quality of the edited file.

    Otherwise, I'd appreciate an abbreviated work flow since what we have isn't really an avchd file.
    1) what should the initial sequence setting be? 1080p avchd like usual or something else?
    2) after editing, what should it be transcoded to? Is this where mainconcept is needed or
    could I use a custom profile?

    I mean for highest end quality. Let's pretend just as a file with no delivery type.

  • @chauncy
    There are many Profiles and Levels of H.264 detailed in the specs, with widely varying quality and efficiency. Driftwood's 176Mbps patch produces high quality H.264 files that are inefficiently compressed at a high bitrate. If H.264 transcoding parameters are chosen properly, bitrate can be lowered without significantly degrading quality.

    In Premiere CS5, sequence type will remain AVCHD 1080p23.976, regardless of which GH2 24H patch is used. You can render a transcoded file at any time before or after editing one or more clips on the timeline, depending on what makes your workflow most efficient.

    For narrative film shooting, I prefer to color correct and normalize all usable footage to a consistent exposure and color palette before it's edited together. This increases the in-memory color depth of the graded video, and I think it's worthwhile to render the results in 10-bit H.264 color. To do this, I fine-tuned a custom Hi10P Level 4.1 Profile in the MainConcept Codec Suite 5.1 plugin with a 75Mbps max bitrate. This plugin provides detailed encoding parameters that are not accessible in CS5's bundled H.264 encoder.

    This type of pre-production transcoding could also be done with the free x264 encoder via command line batch processing. The MainConcept Codec Suite 5.1 plugin was worth paying the licensing fee for the seamless integration it provides with Premiere CS5.
  • got it. I'll take a whack at the mainconcept stuff.
    That makes it clearer.
  • I import my original AVCHD clips directly into avid at DNxHD 175 Mbps. Avid will have promblems with anything that has peaking bit rates that go over 40Mbps. With those type of files I have to transcode with SmartFFmpeg using a loseless setting, that converts the AVCHD codec to a H264 mov.

    As LPowell says the higher bitrate files loose efficiencies and I believe they do not always add up to better quality, and in some cases they can create problems in your workflow. I would rather save time and disc space to have AVID import the files then add another step in the process. The less you have to transcode your original files the better.
  • Software will soon catch up! :-) Try and get GOP1 to work effectively on a lower bitrate... I believe it will prove very very difficult!
  • I use the staxrip h.264 encoder ui to encode my final stuff, using the 'placebo' render setting (highest quality encoding). Slow as heck to encode (I'm talking 1.5fps on an i7 @4.1GHz), but you can get the bitrate as low as 10mbps (sometimes lower) and it looks NO different from the HUGE .mts 85mbps files that come out of the GH2. Can upload some samples if anyone's interested.
  • Okay, here are a couple of samples anyway. Prepare to be blown away...

    1.8mbps (6MB!)
    This is pushing it a bit, but remember that it's full 1080p! This one rendered at 5.5 frames a second.

    7.3mbps (18MB)
    This is pretty much ideal in regards to size vs quality. Looks pretty much like the original when watched in motion. This one rendered at 3.5 frames a second.

    17mbps (43MB)
    This one is indistinguishable from the original, even when paused and pixel peeped. This one rendered at 2 frames a second.

    85mbps (235MB)
    This is the ORIGINAL avchd file.

    Best of all, these files are DivX Plus compatible, and can easily be made to Blu-Ray specs too if selected in StaxRip, though they will require muxing afterwards, which is a simple enough process with TSMuxer.
  • Thanks for this post, Matt. Very helpful and useful insight.
  • @LPowell I got a very important question Perry the (mainconcept codec suite 5.1 Plug) is main purpose is to export video to a final file format right, it does not do anything to the footage when ingested? Finally when exported does it really preserve quality in the final output? Let me know as soon as possible cause I'm thinking on getting it for my system.
  • @TrackZillas
    The MainConcept Codec Suite 5.1 plugin for Premiere Pro CS5 provides both decoder and encoder components that are integrated into Premiere's Import and Export modules. When you drag a clip into Premiere, it detects its video format and uses the appropriate decoder from the ones installed in CS5. The decoder will not alter or transcode the clip, it will simply decode it to Premiere's internal workspace.

    When you export a sequence from Premiere, you choose which encoder to use in the Export Settings dialog box. Each type of encoder provides its own individual interface for setting parameters. The MainConcept plugin's H.264 interface provides access to a much wider range of encoding parameters than any of CS5's bundled encoders. You can get a good idea of whether these features will be of value to you by studying the operator manual for the MainConcept Codec Suite 5.1:
  • @LPowell thanx a lot for the info, I got one question.. before you import your footage into Premiere you said that you color correct all your footage first & convert to a 10 bit H.264 file is that right, can you explain this process for me once more. I'm learning so much from the little bit of info you have provided to me thank you Powell. I'm about to purchase a license from them today I like what they have to offer.
  • @TrackZillas
    Actually, it is the MainConcept plugin's seamless integration that enables me to transcode the footage to H.264 Hi10P as an Export from Premiere Pro, rather than doing it in a separate step beforehand. This allows me to Dynamic Link a clip in a Sequence to an After Effects Composition, which I can then grade using Color Finesse, and apply AE filters to it if desired. Back in Premiere, the footage is automatically replaced by the AE Composition, and I can Export the clip as a 10-bit H.264 file. I can then use the Replace Footage command to replace the original footage with the H.264 footage in the Premiere project.

    While it is possible to simply leave the Dynamic Linked footage in Premiere without Exporting an H.264 version, I find that transcoding it makes it much easier to both manage the footage and preserve Premiere's responsiveness. Once I have a working set of color-graded H.264 footage, I can archive the original footage and make the H.264 files available on the server for editing in projects. This eliminates the chore and confusion of duplicating color-correction settings when reusing footage in multiple sequences.
  • @LPowell Got it now so you bring it the footage in to After Effects for color grading all your footage, than export using MainConcept Encoder 5.1 engine to 10-bit H.264 Wow nice workflow. Do you think you can send me some of the settings your using in your Hi10P custom setting, just got it and I'm a bit confused with all those settings lol... Thank you once again Powell for walking me through your process, and for the great insight.

    GOD Bless
  • @LPowell Color Finesse is a beast use it sometimes on my mac, but the only thing is that it uses so much power that sometimes my computer freezes mind you I'm running on an I7-3.6ghz chip with 12gb of ram. Are you having the same experience?
  • Pssst...Mac OS X users 10.6 (snow leopard) and up:

    ProRes without having to buy FCPX. :)
  • @TrackZillas
    I'm still testing and evaluating the MainConcept H.264 settings - particularly the adaptive quantization features. I'll can IM you a beta 1080p24 settings file to try out in the meantime.

    Color Finesse's full-screen interface is indeed quite heavyweight. It runs fine on my Win7 workstation, though you'd expect it to with a six-core Intel i7, 12GB RAM, and an SSD drive used as a CS5.5 cache disk.
  • @LPowell Nice.. please IM me the beta 1080p 24 settings I would greatly appreciate it. That's a nice system you have here..
  • The 176Mbps GOP1 might not need transcoding to intermediate format. Just pure I-frames. But the MainConcept encoder sounds interesting.