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Disk Drive's Sustained Speed for Hacked Bitrate
  • Dusty42Dusty42

    I have an issue and hope an experienced person can help. I am using a couple of internal disk drives for editing in Vegas; one drive is for all the footage from the camera and the other drive is for rendering (audio/video). When I am working on a video, I do not have anything running. Just Vegas that's it.

    According to spec sheet, the drives have a sustained speed of 110MB/s. Here is the issue that I have during editing.

    For a GOP1 hack like QuantumX v5c B Pictoris (Nick's settings), the stuttering is bearable. For a non-GOP1 like Sanity 4.1, the stuttering is NOT bearable.

    Pictoris is 40Mbps for 24L. Sanity 4.1 is 29.3Mbps for 24L. I like GOP1 settings except the noise. I have tried a few GOP1 settings from Nick's excellent work and noticed quite a bit of noise compare to Sanity. Do others notice that or it's just me? Nick, is there a way to reduce the noise in some of the GOP1 settings?

    Anyway, 29.3Mbps is roughly only around 4MB/s. So a disk drive with 110MB/s sustained speed should be able to handle the bitrate with ease. Do I understand this correctly?

    Thanks.

  • 10 Replies sorted by
  • pdluminapdlumina

    intra vs inter frame, h264 compression being de-compressed, 110MB burst rate vs actual speed + random access times, GOP1 does not equal MJPEG or DVCProHD/DNxHD intra.

  • Dusty42Dusty42

    @pdlumina, I am not sure that I understand your answer entirely. Are you saying that inter frame (non-GOP1) needs to be decompressed and intra (GOP1) does not? The 110MB/s is a sustained speed per spec sheet; it's not burst speed. I do not understand "GOP1 does not equal MJPEG or DVCProHD/DNxHD intra". Please clarify this.

    Thanks.

  • Vitaliy_KiselevVitaliy_Kiselev

    @Dusty42

    Any HDD must be perfectly ok if you work with any hacked bitrate. With heavy formats (like CinemaDNG, etc) it could be not the case.

  • pdluminapdlumina

    @Dusty42 What I mean to say is.. (in no particular order)

    Playback (on VLC, WMP) is not the same as Playback inside an editing application. GOP1 encoding (from the patches) is not the same as video in ProRes/DVCProHD/DNxHD/MJPEG, since these formats are optimized for editing (with intra-frame encoding and low compression). GOP1 H264 on the other hand, requires a lot of processing power to be de-compressed during playback.

    A spec sheet is just that, and the real performance of a drive will be measured once you start using it on your system. Your fastest component on a computer is only as fast as the slower component causing a bottleneck. Simple analogy: take an SSD drive and place it on an USB2 enclosure and plug it to a USB 1.1 port and see what speeds you get out of it.

    Editing in Vegas gives you an edge, since this is one of the few editing applications that playbacks footage on the timeline with ease. However placing a couple of compressed streams of H264 video on the timeline will tax your system. The CPU will be stressed, the RAM will be consumed, the hard drive will be spinning and needles jumping to different places when playing back more than a single stream.

    For plain old playback, sure.. any hard drive will work. For editing is a different issue. Your best bet to edit with comfort and little stuttering is to transcode your footage to an edit-ready format.

  • Dusty42Dusty42

    @pdlumina, thanks for the explanation. What I do not get is that with a GOP1 hack, the performance is ok. But with a non-GOP1, the performance sucks big time on the same system. Go-stop-go-stop. This happens even with just test clips on one stream in the timeline. It's as simple as it can get.

    Is there a quality hit in transcoding the footage from GH2 to an edit-ready format?

  • pdluminapdlumina

    Assuming that when you refer to performance you are talking about pure playback outside Vegas Video: try a different player. For example, regularly I use VLC on Ubuntu fro playback and have no issues, but when I boot up Windows, Media Player seems to play the footage much better than MPC or VLC do.

    If you are talking performance with the clips in Vegas.. again, an editing application is a different story. Of course you'll be able to scrub a GOP1 file with less issues than a non-GOP1. Intra VS Inter frame. In editing you jump back and forth at different positions on your video.

    A quality hit is expected, but no noticeable to the eye. You see, the GH2, GF2, GX1, etc shoot video in a delivery format: Highly compressed H.264. There's a reason that by default the colors are over saturated on these little cameras: delivery. A P2 camera (for example) shoots in an editing friendly format, so there's no transcoding needed.. but there's a price to pay.

  • Vitaliy_KiselevVitaliy_Kiselev

    I do not support this ideas about delivery or editable formats.
    H.264 including long GOP can be edited fine.
    Just NL editors authors are quite lazy, as it requires custom approach and optimizations.

  • svartsvart

    Agree with VK.

    It takes a lot more processing overhead to decompress a heavily compressed file for editing or playing. You'd think that a large file would be harder to render than a smaller file, but it's the efficiency of the (de)compression codec that matters more. It's part of the reason I still use something like Cineform. It decompresses the long GOP into I frames which is easier to edit and/or play. It's a more involved process but I find it easier than dealing with the stuttering while editing AVCHD natively.

  • pdluminapdlumina

    @svart In response to my post, VK just said he disagrees with having delivery and editable formats (which is fine since he's more a hacker than a fulltime editor), then you say you agree with VK and then support the opposite :)

  • Dusty42Dusty42

    Are there any free software to convert non-GOP1 clips to some easy to edit formats for Vegas?

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