MPEG Stills with I-Author

[digvid]

I am using I-Author's Encode and Multiplex utilities to create mpeg stills. I will use these stills in authoring an SVCD with VCDImager. Does anyone know how to make I-Author create NTSC stills instead of PAL? Whenever I create my stills, I run them through the vcdxminfo function (from VCDImager) and it tells me that they are PAL stills.

- digvid

[hvr]

I just ran one still mpeg someone sent me once through vcdxminfo:

he created the BMP with the resolution needed for NTSC and then ran in through enc and mux, while setting the type to 'low res E1' or something like that...

the only prob with it, is that the framerate does not match the resolution
but the IEC62107 spec requires the frame_rate_code to match...

(in theory you could use a hex editor to change those 4bits to match %0011 instead of %0100 in the sequence_header...)

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Code:</font><HR ></TD></TR><TR><TD><FONT SIZE=-1><PRE>&lt;mpeg-properties&gt;
&lt;version&gt;2&lt;/version&gt;
&lt;hsize&gt;704&lt;/hsize&gt;
&lt;vsize&gt;480&lt;/vsize&gt;
&lt;frame-rate&gt;25.000000&lt;/frame-rate&gt;
&lt;playing-time&gt;0.000000&lt;/playing-time&gt;
&lt;packets&gt;10&lt;/packets&gt;
&lt;video-bitrate&gt;120000&lt;/video-bitrate&gt;
&lt;video-e1 /&gt; &lt;!-- still --&gt;
&lt;/mpeg-properties&gt;</PRE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

[digvid]

I have done some more experimenting this morning and discovered that I can make either a hires (704x480) or lores (480x480) SVCD NTSC still by doing the following:

1) Use the StreamWeaver tool to encode a hires or lores 256-color bmp to mpeg. To make it encode as a still instead of a video, you have to double-click on the bmp after you have added it to StreamWeaver and choose "re-encoce as MPEG still."

2) Run the resulting mpeg file through I-Author's muxing utility. This creates an NTSC (29.97fps) still instead of PAL, which is what I-Author's Encoder creates. Note that in the muxing utility, you can choose either hires or lores, whichever is appropriate.

This is the best method I have found so far. I would be interested in knowing if someone has a better way, or if they can improve on this method. Some questions I have are: 1) Should I really have a hires and lores still multiplexed into one stream, and 2) VCDImager gives a warning that there is no user scan data in the stream. Is there a way I can add this user data? Muxing with bbMpeg is not an option because it automatically turns the stream into a video instead of a still.

- digvid

[hvr]

warning: for IEC62107 compliant svcd's don't use I-Author's hi-res setting, always use the lo-res still setting!
(fyi, this setting just tells the muxer which stream_id to use... and IEC62107 requires the same stream_id $E1 for hi-res as well as lo-res!!)

the lores+hires interleaving is only required for VCD2.0 if you want hi-res there!!! for svcd's you use either lores _or_ hires, that's why there is only one stream_id reserved for stills, whereas for VCD2.0 there were 2 stream_id's, namely $E1 for lo-res and $E2 for hi-res, in order to distinguish the two still picture streams...

that scan_data thingie is not that vital, it's just mandatory in the specs, that's all, and that's why vcdimager warns
most players don't care about it anyway... and if they do, it usually just disables scanning capatibility...

but actually, for a one-picture stream, what need is there to add scan information?!?

anwyay, just to make one thing clear, the muxing process does just packetize the elementary stream and mark it with the corresponding stream_id (which can be 'fixed' in a hex-editor afterwards as a hack...), which the encoder must have created as still in the first place...
motion video and still picture look quite similar... and are decoded by the same algorithms, they just differ in their structure...

[digvid]

Aha! That clears it up for me. I was confusing VCD and SVCD requirements. I think now that my method should work as long as I use the lo-res flag when muxing with I-Author's mux utility. This creates (according to vcdxminfo) an E1 still stream at 29.97fps, either 480x480 or 704x480 and at 2600kbps bitrate.

[digvid]

Okay, here is the method I have decided on for making SVCD-compatible mpeg stills for use with VCDImager.

1) Load a bmp, tif, etc. into TMPGEnc
2) Set stream type to "video only"
3) Click the settings button and go to the video tab
4) Set to mpeg-2 video and set your resolution to 704x480 or 480x480.
5) Set aspect ratio to 4:3 and fps to 29.97. NOTE: You could also use 23.976 w/3:2 pulldown
6) Set bitrate to CBR and use the average bitrate that you used on your video files
7) Set VBV buffer size to 112
Set encode mode to non-interlaced (or 3:2 pulldown if you used 23.976 fps)
9) Set motion search precision to highest quality
10) On the advanced tab, set video source type to non-interlaced, bottom field first
11) Set source aspect ratio to 4:3 525 lines
12) On GOP tab, set output interval of sequence header to 1
13) Choose force picture type setting and click the setting button
14) Click the frame to make it an I-frame, then press OK
15) On the quantize matrix tab, choose whatever settings you normally choose for svcd.
16) Encode!
17) Run I-Author's mux utility
1 Rename the resulting m2v file to have an mpv ending
19) Press the browse button for the video edit box and browse to the directory where your m2v file is stored
20) To the right of the video edit box is a combo box that should say "auto." Change it to read "Low res still picture (E1)".
21) Check the "PS format" check box
22) Hit the "start" button, then exit
23) You can rename the resulting .ps file to have an mpg or m2p ending if you want
24) Run VCDImager's vcdxminfo function on the .mpg file like this "vcdxminfo --generic-info myfile.mpg". It should show statistics for your file with the bitrate, frame-rate, resolution, etc. that you picked in TMPGEnc. Also, if should say (near the bottom) that your file is an mpeg still.

*** DISCLAIMER *** This is not the only way, and maybe not even the correct way to do this, but it seems to work for me. Also, VCDImager will complain (during vcdxbuild) that the stills do not contain user scan data. However, this does not seem to affect the disc on any player that I have seen. If anyone has a "better" way, I would be interested in learning about those too!

- digvid

[timmy_boi]

all this to have a still movie?

this is for the menu rite? like a still?

can someone explain to me why do you have to go though all this instead of going to adobe premiere and importing the bmp file, exporting the avi movie, then recodeing it as a mpeg?