Results 1 to 6 of 6

Thread: MPEG1 capture quality, SteadyMove and pixel ratio issues.

  1. #1

    Default MPEG1 capture quality, SteadyMove and pixel ratio issues.

    Hi

    I have a Sony DSC-T1 digital camera which also captures video at "near DV quality". Now, this camera fits in my shirtpocket and has a battery that lasts for ages and so represents a fantastic alternative to my DV camcorder which is bulky-ish and which, whenever I want to use it, I find I need to spend three hours charging the batteries. The Sony can only shoot 6 minutes of footage at a time, but since I edit in camera, rarely take a shot lasting longer than 10 seconds, and would be able to dump this footage back onto my PC at the end of each day, I don't regard this as a serious drawback given the camera's go-anywhere portability.

    However, it does present me with some challenges and, as a newbie to Premiere Pro (and video editing in general), I am struggling to overcome them. So, I am kindly requesting assistance or advice from anyone who can help.

    Here are my questions:-

    1. Video quality - it appears that this camera captures 640x480, 30 frames/second, in editable MPEG-1 format (i.e., footage consists of I-frames entirely). Sure enough these clips can be imported into Pro and trimmed as if they were AVI files. My aim in all of this is to produce DVDs of my footage. Given this, is there any point in converting these clips to AVI files prior to editting or would I be wasting my time? I mean, if the finished DVD is in a compressed format, and I am capturing in a (albeit different) compressed format, and able to edit it, why even try to decompress (even losslessly using HuffYUV)? I assume it will have zero effect on end picture quality but is this correct?

    2. Encoding time - I produced a rough-cut 5 minute movie in this manner and exported it directly to DVD from Pro.... and it took an age! About 20-30 minutes to transcode into DVD format all told for a a 5 minute DVD. Is this because it has to convert from MPEG1 to some neutral format and then to MPEG2 for the DVD? If I converted the captured footage to AVI before editting would this reduce this "transcoding" time or would the overall amount of time spent converting and deconverting the footage over the entire production cycle work out to be the same?

    3. Pixel ratios - I can't seem to setup a project so that it automatically converts these 640x480 clips into 750x576 PAL format on the timeline. I have the appropriate box checked in the Project Settings/General settings tab to convert sequences to project settings but it doesn't seem to do anything. At the moment, then, I have to select all the clips and use "Interpret Footage" to change the pixel ratio to 1.067 (DV1/PAL). Am I missing something? I'm also worried that this pixel conversion isn't right and that on the completed DVD the scenes are truncated - as if I have enlarged the pixels too much. Should I use square pixels instead or some different ratio?

    4. SteadyMove plug-in - one of the biggest drawbacks I found when I watched my sample 5 minutes DVD on my telly, wasn't so much the picture quality (although it clearly isn't DV quality) but the camera shake. Since this little camera is so tiny and it has no image stabiliser built-in I had overlooked this as a possible problem. Based on one viewing I would go so far as to say that I could live with the picture quality but not the camera shake and so this one factor alone would prevent me using it for more than little clips I might e-mail to friends and family. However, I have installed the SteadyMove plug-in and tried to apply it to one of the clips on the timeline and it didn't seem to make any difference in the monitor window. All that happened was that the clip was clearly zoomed in a little and perhaps a little more blurry, and that it took a lot longer to render in the monitor window - I guess this last bit is to be expected? However, when I exported the "steadied" clip to an AVI file and played the resulting file it was miraculously stabilised! Is there any way around this? If not, it means I have to trust to faith that all shots ('cos I'll probably have to apply this effect to them all) will be stabilised but I just won't be able to tell until they are rendered and exported.

    Any help, assistance greatly appreciated. I'm not looking to use this little Sony instead of my camcorder all the time, but the prospect of being able to have a ready-to-shoot video/still camera always on me means I would take a lot more footage and capture a lot more precious moments than I would otherwise do. I have 3 small kids and toting a camera bag and batteries around whilst trying to keep the nippers under control is a nightmare. At least this way, I will have halfway decent footage of moments which otherwise I wouldn't have been able to capture at all. That to me is worth the effort of trying to make this work as best I can

    thanks in advance

    mrsafety

  2. #2
    Join Date
    Nov 2003
    Location
    Kent
    Posts
    11,514
    Blog Entries
    24

    Default

    I'll have a quick stab at answering your questions in the 5 minutes I have of my lunch break.

    I always feel that using Premiere for editing such footage is a tad overkill. Why? Well, Premiere's geared towards editing DV content and if you select the appropriate preset with files captured to DV AVI, editing and previews are in realtime (no srubbing required except for effect). Morever, the type of footage from "non-DV" cameras (eg digital still cameras) does not lend itself well to high end productions, so the bells and whistles associated with Premiere probably won't be necesary. The typical user with this format of footage would typically just want to do a few edits then output to DVD or VCD.

    This is the main reason for converting before editing. If you convert to a format that Premiere nativelty supports, you get the benefits of realtime editing.

    Transcoding times are laregly dependant on your hardware. The better the PC, the faster the encoding times. Could you post your specs?

    The above said re: your inputs, and as you've already paid for Premiere, I would recommend creating a custom project which matches your video source. Go to the tab behind the default on the new project window to create a custom project and select video for windows. You can then match your video settings. This will then fill your entire preview window.

    I've never really mastered the science of pixel ratios - its more of an art I've picked up. You tend to "see" whether you've messed up the pixel aspect ratio when outputing a few seconds of video.

    That's not much help, but as long as you always match the source and destination for playback on a PC you'll be fine. When you finally convert to PAL for use on a DVD for TV playback, you may see that the image becomes stretched (rather like, but nowhere near as notciable as wathcing 4:3 on a 16:9 TV). You can get around this by centering the image, expanding it and cutting of the the excess at the top and bottom. Finally, if you maintain the aspect ratio, you'll get bars at the left and right. The first scenario is the most likely.

    I've tried and failed to get the steady move plugin (that ships as standard) to do anything more than make a mess of my footage.

    If I've missed anything, give post back

  3. #3
    Join Date
    Feb 2004
    Location
    Bracknell, Berkshire, UK
    Posts
    5,191

    Default

    You won't get better from a steadymove filter. In truth I've not played with it but I do understand how it (they?) work.

    They are trying to remove camera shake right? So, what is at the edge of one frame may be just off the edge in another frame and similar on the other side of the screen. What they do is take a smaller area of your picture where it can be assumed will always be in frame (so to speak). This smaller 'window' is moved around your frame compensating for any camera shake. As a result of this, the 'good' portion has a border around the edge and finally the whole thing is zoomed digitally to fit your frame again.

    So basically, you will always get a slightly cropped and zoomed result from using the filter.

    Hope that all makes sense

    Not sure if it exists in Premiere but Photoshop has a rally juicy 'unsharp' filter which will then help tidy up the edges, sharpening them again. btw, that's not a typo. The UNsharp filter sharpens the image. really!

    There must be some sort of sharpening filter though, surely, even if I haven't bothered looking for one yet.

  4. #4

    Default

    Cheers Marc & Millsy

    Boy, you guys reply fast!

    To clarify a few things:
    1. I realise Premiere (Pro) does loads more than I need and will ever use - e.g, can't ever see myself chroma-keying, using mattes, fancy transitions, etc etc - but (a) version 6 came preloaded with my PC anyway and (b) my main concern was for stability, reliability and compatibility - I've read too many message boards concerning problems with Pinnacle at el and incompatibilities between drivers, mobos, goodness knows what else and I just wanted something I knew would work time and time again. Plus I like getting to grips with a complex product and becoming fluent in it - I'd just get bored with something noddy.
    2. My spec is P4 3Ghz, 1Gb Ram, 2Gb page file, 2 x 160HDD (1 for XP, swap file, programs and archive stuff; the other for video footage). Brand new (Sony) PC. Surely this is good enough to whiz through transcoding a 5 minute video? So why didn't it?
    3. I don't understand the comments about what Premiere "natively" supports and what it doesn't. Since I can open the MPG captured files, trim them frame by frame and manipulate them like any other files, doesn't this mean their natively supported? Based on your feedback it seems like there is no point in me converting/reconverting these files -the quality I get is as good as I'll get so I have to decide if I can live with it or not?
    4. Sorry if I misled you about the SteadyMove thing - my concerns with whether my clips were filling the whole of my TV screen, and whether they were cropped in the process, was to do with the pixel ratio adjustment not SteadyMove. Again, based on Marc's comments, sounds like I'm not necessarily doing anything wrong with my pixel adjustments - just that such adjustments are imperfect. Doesn't answer the question of "Why doesn't Premiere do this automatically when I check the adjust box in the project setting window" though does it?
    5. Marc - I won't ever be creating output for a PC monitor - or if I do, it will be much reduced and compressed in order to be e-mailed so all I care about is the file size rather than what it looks like! My primary focus is on creating DVDs of family events, etc so I will always want to view this 640x480 footage on my TV screen. What would it look like on my telly if I did the whole project as 640x480?
    6. Back to SteadyMove though - why doesn't the stabilising effect render in my monitor window (is this why you say the file format's not natively supported?) but it does when I export the timelined sequence to AVI?

    What I'm going to try over the next day or so is to make one DVD with 3 chapters on it, each 5 minutes long:
    Chap1 - rough-cut footage of analog footage captured on my PC
    Chap2 - rough-cut footage of MPG 640x480 adjusted to PAL
    Chap3 - rough-cut footage of DV/PAL material

    I have already seen big differences in quality between 1 & 3 - but there's not much I can do if the source material is only available in 8mm analog format. What I am interested in is the difference between 1 & 2 because, to be quite honest, if the footage from my little Sony is better than analog-converted-to-DV, and doesn't give you a headache from camera shake, it could be a major addition to my source of material. What I have in mind is creating a DVD for each year containing family events and using combinations of DV footage, Sony "still" footage and still snapshots to form an overall montage for the year. As long as the Sony footage is watchable in this kind of context (ie, there is less of this material than there is of the DV footage) I think it'll be okay.

    Thanks again for the responses so far

    mrsafety

  5. #5
    Join Date
    Nov 2003
    Location
    Kent
    Posts
    11,514
    Blog Entries
    24

    Default

    If you're going to convert to DVD, then your finished film needs to meet the PAL DVD standards. In that respect, you have no choice but to use a 720x576 framesize.

    Concerning encoding times, again this varies greatly. It depends on a few factors such as the method of encoding used. Broken down into it's simplest form, you have Constant Bitrate (CBR) versus 2pass Variable Bitrate (VBR) the later will always be longer than the first as the software analyses the video in the first run, then varies the bitrate accordingly when actually encoding for the second run. There are then varies other settings (most of which I won't even pretend I understand) that can speed up or slow down the encoding process with at a trade-off with quality. Moreover, if you're applying frame rate conversion and or other filters on top of this, I would have thought encoding times would increase (but don't have empirical evidence to back this up). I would have thought encoding times would go up if you haven't previously scrubbed the timeline, so I guess this must be true!

    Finally, encoding is CPU intensive and hoggs resources. If you're actively running other applications, less CPU processing is spent on the encoding process and the encoding time will increase.

    So, to summarise, if I was editing the footage, I'd convert to DV AVI then import this. Infact, this is what I DO do when given analogue footage that's all screwy

  6. #6
    Join Date
    Mar 2005
    Location
    Boston, MA USA
    Posts
    16

    Default

    I'm pretty much a newbie in this field, but I have been learning Premiere Pro over these past 2 weeks. Like you, I'm using a Sony digital camera (DSC-P41) to shoot footage and using that material to do sort of a 'practice movie' while I learn. The 1st trouble I encountered was that imported mpeg1 shot with the p41 will open up in Premiere but the format is not ideal for editing (when I first did this my video was pretty choppy and the audio was out of sync). A way around is convert it them to DV AVI using virtualdub. I have not tried this, but I did find a Premiere plugin called 'MPEG PRO" from mainconcept, which give you new presets for Premiere when you start a new project that will allow editing of mpegs without any trouble.

    http://www.mainconcept.com/mpeg_pro.shtml#standard

    Since I'm still learning, I haven't noticed what actually happens when I import the mpegs from the camera into a Premiere DVD project; I know the camera's images are a little smaller than DVD format, but I don't see the difference.

    - Derek

Similar Threads

  1. Studio 9 wrong aspect ratio capture
    By pucela in forum Pinnacle Studio, Edition including Avid Xpress and Liquid
    Replies: 0
    Last Post: 06-17-2006, 11:44 AM
  2. DV Capture Aspect Ratio Problems
    By Bob Hamilton in forum General video editing software help and advice
    Replies: 9
    Last Post: 11-03-2005, 11:43 AM
  3. Making size ratio smaller but keeping quality
    By Citizen in forum General video editing software help and advice
    Replies: 3
    Last Post: 08-29-2005, 01:37 PM
  4. Sony DCR 109E hard disk capture ?? / quality issues
    By Paulh in forum Hardware Problems
    Replies: 6
    Last Post: 01-04-2005, 01:05 PM
  5. Quality issues.... analogue through pinnacle linx usb
    By dinks in forum General video editing software help and advice
    Replies: 2
    Last Post: 11-17-2003, 03:44 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •