David Esp Video Technical Blog

Context:

• I had a Sequence  containing two video tracks, each having a pair of (associated) audio tracks.
  • Sequence Properties: 1080p, square pixels, 25 fps.
  • One track contained a single continuous clip of duration just over one hour[01:02:46:10].
    • Properties: 1080p, square pixels, 25 fps.
    • Format: Sony XDCAM-EX: MPEG2 @ 35 Mbps VBR: MPEG2HD35_1920_1080_MP@HL
  • The other track contained a number of discrete clips, intermittently spaced over that time.
    • Properties: 1080i, fat pixels (PAR=4/3), 25 fps (50 fields/sec), UFF.
    • Format: Sony Z1 HDV: MPEG2 @ 25Mbps CBR
• This sequence, as it stood, played fine.
• Then I nested that sequence (seqA)  inside another sequence (seqB).
  • Still played fine

Problem:

• Then I did some multicam “music video” edits, mostly near the end of the sequence
  • Now, when I hit the spacebar to play seqB, there is a delay of several seconds before playing actually begins.
• If I try re-creating from scratch, by nesting seqA inside new seqC then seqC plays fine.
• If I try copying the multicam-edited elements of seqB (the multicam edit-sequence) into new seqD (a new multicam edit-sequence) then the sluggish response to [Play] still occurs.
  • Doh!  I had hoped that would be a simple workaround..

Partial Workaround:

• Following web-advice regarding a broadly-similar issue with multicamera sequences comprising spanned clips (e.g. AVCHD or Canon’s H264) , I tried transcoding the footage to GoPro-Cineform
  • Based on Adobe’s workaround-advice regarding broadly similar problems with long hence spanned AVCHD footage.  My footage is not AVCHD, but the main clip is Sony XDCAM-EX, which has some features (like spanning) in common with AVCHD.  Worth a shot!
    • On a 4-Core i7 PC with GPU, it encoded at about real-time, which in my case was about an hour.  CPU was only 25% i.e. equivalent to a single core
  • Replaced the relevant clip in seqA.
    • To my delight, the clip-markers (in that clip in seqA) were retained/applied in that replacement footage.
• However, the sluggish [Play]-start remained, though possibly shortened, from about 6 seconds to 4 seconds.

Further Workaround:

• Duplicate seqA
• Nest it in a separate multicam sequence (seqE)
• Do multicam edits on further segments of the event in that (seqE)
  • Intend later to nest/sequence usable bits of each multicam edit-sequence in a Master sequence.
• Where there’s a will, there’s a workaround…
  • Still, I expect better of Adobe…
  • I lost about 3 hours to this (including web-searching, waiting transcoding and general experimentation).

Further gripes:

•  God it’s clunky!
  • Every time I stop multicam-preview to tweak the multicam cut timings, then return to multicam editing, I have to remember to activate the multicam monitor, not the timeline (where the tweaks are done).  Unfortunately my reflex is simply to hit the spacebar.  It is a nuisance to have to fight that reflex…
  • Every time I stop multicam-preview, it leaves a cut at the final position of the playhead.  Not useful and simply clutters the timeline, distracting from real cuts.
  • Zoom [+] only affects the Timeline, not the multicam monitor.  As a result, I tend to set the playhead position using the timeline.  Doh! must remember to click (activate) back to the multicam monitor once more…
  • Ranged (duration not zero) markers are great but adjusting their right-hand end can be tricky, since this can change the playhead and/or timeline-display.  Things snatch and interact that shouldn’t (I feel).
  • Sony Vegas is far better in these respects, though not in some others, so I’m sticking with Adobe…
• Unexpected Preview-Rendering is happening…!?  How come?
  • In principle, that shouldn’t be happening?   I have a state-of -the-art (4-core i7 & GPU) laptop specifically for CS6, no effects applied, just cutting between two cameras, some plain dissolves (between segments of the multicam sequence) – but surely the Mercury Engine should take them in its stride?  (or can’t it cope yet with multicam?).

Web-Search:

• Google:[adobe premiere multicam cs6 slow buffering]
  • http://adobe.hosted.jivesoftware.com/thread/1012921
    • Thread: CS6 becomes less responsive over time in Multi Sequence
    • tinklevision256, May 28, 2012 6:49 AM
      • CS6 becomes less responsive over time in Multi Sequence
      • I have a multi sequence with 4 lanes of video (2 x h264 and 2 x all I-frame). I notice that when I start the project (About 24 mins long) all is nice and responsive, but as I progress all becomes much slower/slugggish, such that now when I press play it takes 2-4 seconds for the play head to move. It seems like some kind of buffer thing.
      • Any ideas ?
      • Mac Pro 12 core 2.66 Quadro 4000 46G Ram Internal Raid 5
    • Jim Simon, May 28, 2012 6:18 PM
      • In that case, it’s possible you;re running into a known bug with CS6 and AVCHD whereby things get sticky and slow.
      • At this point, about the only thing you can do is convert the AVCHD into something else, or use an earlier version of PP.
      • {BUT unsure if this is relevant to me given that my footage is not AVCHD but MPEG2]
        • {Though these MPEG2 formats, like AVCHD, imply indexing, which Cineform would avoid}
    • tinklevision256, May 29, 2012 6:39 AM
      • My footage is not AVHCD, its from Canon 5d/7d and 5d MK III (Al I-Frame).
      • It happened with 5.5 also.
    • Jim Simon, May 29, 2012 8:13 AM
      • 5.5 didn’t have this issue,
      • so if the problem happened there as well, I’m not sure what it could be.
    • Jim Simon, May 29, 2012 8:08 AM
      • Quote: <>
        • http://forums.adobe.com/message/4407239#4407239
      • Quote: <>
        • If you don’t have an older version {of Premiere} to fall back on, try converting to UT AVI files.  It’s a free, lossless codec that works pretty well with Premiere Pro.
          • http://www.videohelp.com/tools/Ut-Video-Codec-Suite
            • Ut Video Codec Suite is a lossless video codec for Windows, which is implemented as a VCM codec (also called “VfW codec”). YUV an RGB lossless.
            • Best lossless codec. Way faster than Lagarith.
            • Definitely one of the best lossless codecs. It is efficient, fast, supports multithreadding and runs absolutely stable. And even better: It still improves, because the developer heavily optimizing his code.
            • I’ve been using it for well over a year now, & haven’t found anything better for HD intermediates…  UT Video just works, works with every app I’ve tried, & works well across 7 ult 64 & XP Pro SP3 32.
        • {Or in my case I would use GoPro-Cineform}
    • tinklevision256, May 29, 2012 8:20 AM
      • I have had the same issue in both 5.5 and 6 in Multi-Sequence projects when using H264 codec natively.
      • I am not using AVCHD
    • DanielNL, May 29, 2012 1:56 PM
      • Got the same problem. I have mutiple 10min+ AVCHD files from a Canon HF G10.  Can’t edit the last few minutes of each file because CS6 becomes very slow. When I press play the audio plays fine but the video freezes in the program monitor. Never had the problem with CS5.5
      • Looks like they still didn’t fixed it in update 6.0.1 ?? Just installed it but I still have the problem.
  • http://forums.adobe.com/message/4407239#4407239#4407239
    • AVCHD Workflow help
    • Prof-McAlexander, May 14, 2012 8:45 AM
      • Is there any reason to transcode the AVCHD files to another codec before editing in PP?
    • ExactImage, May 14, 2012 11:41 AM
      • …I’ve found a problem with some AVCHD footage in CS6 that didn’t exist in CS5.5, namely that of long / spanned clips.
      • Shorter (non spanned) clips don’t appear to have a problem, and if that’s what you are feeding in to CS6 then stay with AVCHD, there is no reason to transcode.
      • Hopefully Adobe will fix the problem in the first update.
    • ExactImage, May 14, 2012 3:39 PM
      • …there is a related bug in Media Encoder.  Drop this (30 min spanned) file on to a sequence in 5.5 and export via media encoder and it takes around 80 mins to export to H264.   Media Encoder CS6 starts off saying about 80 mins, then it goes up, and up, and up, and up and TBH I gave up at 9+ hours and only 30% encoded.
      • The problem appears to be that it’s reparsing the entire file all the time and this can be seen in the Windows resources monitor (where you can see the files than an App has open and how much it’s reading).
      • Hopefully they figure this one out soon because it’s causing me major problems.
      • Yes, I’ve submitted a bug report complete with a sample project demonstrating the problem.
    •  ExactImage, May 14, 2012 4:01 PM
      • I’m not the only one.  See other topics that mention problems playing back multiple video tracks and multicam.
      • It makes sense that multicam is the one place it showed up first because that’s where you tend to have the longest clips.
      • And….it’s not just one computer.  We have the same problem on 3 PCs here, and a Mac Pro and another editor off site – same problem – repeatable every time.
      • That’s why I sent Adobe a sample project complete with source media.   They grabbed it late Friday so hopefully some one will have recreated the problem in house by now.
    • Jim Simon, May 15, 2012 1:13 AM
      • Something is definitely wonky with AVCHD in CS6.
      • I also now understand how Harm was getting 50 MB/s reads when trying to play this stuff.  It’s not the media, it’s CS6.  Opening the same exact file in CS5 works no problem, and reads at the expected 5 MB/s.
    • Jim Simon, May 15, 2012 9:57 AM
      • Yeah, this one is definitely a show stopper.
    • ExactImage, May 15, 2012 2:02 PM
      • Just got an email from Adobe acknowledging the problem and it’s been passed to engineering.
    • ….
    • {BUT no fix has appeared, it seems…}
    • ….
    • Greg Baber, Jan 4, 2013 8:47 AM
      • The bug we’re speaking about is only about long format, spanned MTS clips.  Your issue may be something else.
      • I will say this – Mercur enabled card and RAM being available is not going to have much impact on AVCHD playback.  The main influence on playback is actually the CPU.
      • This document goes over how to work with this footage — http://helpx.adobe.com/premiere-pro/kb/audio-video-glitches-avchd.html
• http://helpx.adobe.com/premiere-pro/kb/audio-video-glitches-avchd.html
  • {As of 2013-02-20: Problem acknowledged, not yet fixed, workaround= transcode the footage}:
    • …the GPU doesn’t process the video footage, so the video configuration doesn’t have much effect on the performance.
    • There is a known issue for Adobe Premiere Pro CS6. AVCHD files that are spanned can cause the system to freeze up while scrubbing the software. Also, the audio can sometimes disappear after a set amount of playback.
    • At this time, there is no fix for this issue.
  • {Workarounds}:
    • For now, the best workarounds are to make sure that when recording, keep the video files short enough that the camera does not use the file spanning feature.
    • Also, transcoding the footage to a different format resolves the issue as well.
  • {Transcoding-Codecs}
    • Suggested codecs for transcoding
    • When transcoding, it’s best to use a good intermediary codec. You want to keep the file size small but keep the quality of the original clips. Here are a few suggestions.
      • P2 settings are included with Adobe Premiere Pro and make a good step. This step creates a similar file structure to the AVCHD files and must be ingested in the same fashion.
      • UT is a free codec available online here. This format is a Windows codec, so it is available under the AVI file type. You can use this format on both Windows and Mac, but is primarily used on Windows systems.  Add an encoder preset within Adobe Media Encoder before it appears as an option in Prelude.
      • DNxHD is a free codec available online here. This format is primarily Mac-based, so it is available under the QuickTime file type.  It is available on Windows and Mac, but is primarily used on Mac systems. Add an encoder preset within Adobe Media Encoder before appears as an option in Prelude.
  • Transcoding-Tips:
    • To transcode the footage, you can use Prelude, if you are using Production Premium or the Master Collection editions of CS6. Otherwise, use a third-party program for transcoding.
    • From within Prelude:
      • Click the Ingest button in the upper toolbar.
      • Choose the storage card for the camera, or the directory that was moved onto your hard disk.
      • Make sure that the Ingest dialogue says that View As AVCHD.
      •  Select the clips that to Ingest.
      • Under Transfer Options, click the checkbox to Transfer Clips to Destination.
      • Choose Transcode.
      • Under Transcode, choose the format you want to transcode the files into.
      • Click Ingest to copy and transcode those files.

This entry was posted on Thursday, February 21st, 2013 at 17:07 and is filed under Adobe, AVCHD, multicam, Prelude, Premiere, Sony EX XDCAM, transcode, workflow, XDCAM EX. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.