Re: [VCDImager Bugs/Devel] Re: new vcdimager

[Mike Bernson]

Herbert Valerio Riedel wrote:
> 
> btw, the developer list is still at address@hidden :-)
> 
> On Sun, 24 Dec 2000, Mike Bernson wrote:
> > I have still have a problem with times on the current
> > vcdimager. The vcd plays but does not show time on the
> > front of the dvd player. The player also lockup when
> > trying to fast forward or do time searches.
> are you really talking about VCD2.0? or are you refering to SVCD1.0?
> 
I am doing vcd2......

> as for SVCD, I haven't filled search.dat yet, since I wanted to have an
> alpha release out for this year to get more feedback from a wider
> userbase. I'll put this issue as a 'known bug' on the hp.
> 
> > We still do not have a vaild PSD.VCD file. Does someone
> > have the format info for this file. I would be willing
> > to look into build the file correct.
> u really mean '/VCD/PSD.VCD'?
yes.....
> 
> I'm quite sure it is valid already... I couldn't see any difference when
> comparing them to other VideoCDs not made with vcdimager...
> 
> btw, all information about those files is in /libvcd/vcd_files_private.h,
> and it's quite complete thanks to jens.
> 
> > Is there any other files that deal with time info. I would
> > like to have the time function working. I would be willing
> > to help/do the need work but do not have the standard doc
> > for vcd or svcd. The doc I have does not go into the detail
> > for this file.
> 
> ...the main problem is more how to do it the-right-way(tm) without
> breaking the actual program design too much :-)
The problem is that the time display is blank on vcd and time function
do not work. With /vcd/psd.vcd file I get a lenght and time on the
display of the dvd play but still can not do fast forward.
The dvd play is a Philps DVD711.
> 
> the correct way would be to scan the mpeg streams beforehand while
> building the search.dat timestamp list, and then reread them when creating
> the image. (the idea is not to have to seek around in the output image
> file, since the output should be pipe-able in future, as to be able to burn
> a VCD on-the-fly...)
> 
> the efficient way would be to build the search.dat table while writting
> the image.. but this would imply to have to reserve some fixed space for
> that search.dat file, and after having finished writing the image to have
> to seek to the beginning again, to write that file... well... actually
> that'd be neat, but it would result in some ugly-hack...
Does a vcd2 have a file called search.dat or is this a svcd thing.
> 
> another way was to just guess where those timestamps may be... this would
> be efficient and not-too-hacky but everything else but correct...
> 
> ...
> 
> it'll be the first way, the correct one, I'd want to use...
> maybe there is a clever way to scan an mpeg2 stream without having to read
> _every_ mpeg packet and still be able to build a correct search.dat...
> 
> PS: can anyone tell me, what the header of an MPEG streams system header
> exactly looks like? especially for mpeg1... (and then, if it's still valid
> for mpeg2 streams...)
> 
> since I've had to add the following 'hack', in order to get playable
> MPEGAVxx.DATs... (I had some mpeg1 streams, whose first 2 mpeg packets
> were otherwise detected as 'MPEG_TYPE_NULL'... since they contained only
> a packet, a system and a null block...)
> 
> from vcd_mpeg.c:
> 
>               case MPEG_SYSTEM_HEADER_CODE:
>                 {
>                   int size = _bitvec_get_bits32 (data, offset, 16);
>                   /* fixme -- boundary check assert (offset + 16 < 2324 *
> 8) */
>                   offset += 16;
> 
>                   /* just a hack, since I don't know exactly what the
>                      format of the system header is */
>                   if (!extended_type_info && size > 6)
>                     switch (_bitvec_get_bits32 (data, offset + (6 * 8),
> 8))
>                       {
>                       case 0xe0:
>                         return MPEG_TYPE_VIDEO;
>                         break;
>                       case 0xc0:
>                         return MPEG_TYPE_AUDIO;
>                         break;
>                       default:
>                         /* noop */
>                         break;
>                       }
> 
>                   offset += size * 8;
>                 }
>                 break;
> 
I will start soon to look at creating svcd from linux. The mplex for this 
does not yet have a profile for handling svcd but I can look at that. It
is getting to the top of my list. The encoder does build vaild mpeg-2
streams.  Is there anything beside the 480 x 480 limit. and max bit
rate of 2200 that I should known about before trying to build svcd.