Forced aspect ratio DivX/XviD playback on the Philips DVDR 3390

[yukichigai]

I have an old DivX-certified Philips DVD Recorder I've been trying to put to use. On a whim I wondered if it would be possible to correctly play back video encoded with a PAR other than 1:1. I found mention that other Philips players (5000 series) could do so if the right tags were set, but no mention of what those were. So I tried a few things. Encoding the AR into the XviD stream itself does not work, nor does overriding it with something like mpeg4modifier.

Short version: you have to override the value for Width (or Height) specified in the AVI itself.

In my case, I used abcAVI Tag Editor to make the change (though there's probably other software can do it). It can be done through the Force Frame Size option under the Hacks & Tweaks tab. I encoded some video at 352x480 (CVD resolution), then overrode the frame size to 640x480 in the muxed AVI. The resultant file played back in proper 4:3 aspect ratio in my DVD unit with no errors.

Anyway, I just wanted to put this information out there in case anyone else down the line tries to figure out if/how to do this. You can, and that's how.

EDIT: For other aspect ratios, setting the frame size width above 720 will render the file unplayable on the 3390. Any values under that seem to be fine. In other words you cannot use this method to force 16:9 720x480 content to play back at 852x480. You CAN use it to play it back at 720x404 though.

[kurkosdr]

Interesting... does it also work for the override that would allow no-resize rips from anamorphic DVDs, that is, 720x480 that should be displayed as 854x480 and 720x576 that should be displayed as 1024x576?

I had some limited success with Mpeg4 Modifier, but only on later-model players. Maybe this hack will work? Can you try on your player?

[v0lt]

I used MPEG4 Modifier and it worked well for Pioneer DV-575A.

[yukichigai]

Originally Posted by kurkosdr

Interesting... does it also work for the override that would allow no-resize rips from anamorphic DVDs, that is, 720x480 that should be displayed as 854x480 and 720x576 that should be displayed as 1024x576?

I had some limited success with Mpeg4 Modifier, but only on later-model players. Maybe this hack will work? Can you try on your player?

I gave it a go with some 720x480 content encoded using the same preset, just with the width forced to 852 (divisible by 4). My player refused to play it, saying file is "not supported".

I haven't given up though, and I have a few theories as to what may be causing it to be "not supported". It may be as simple as the player not supporting files with a resolution above 720x480, regardless of it being an overridden value or not. 852x480 might not be playable, but what about 720x404?

This'll take a bit though since I've lost the remote to the damn thing and can only play back the first file on the RW disc I burn. If I find a solution I'll let you know.

EDIT: might also be limited to multiples of 8 or multiples of 16. That used to be a thing.

[kurkosdr]

Originally Posted by yukichigai

852x480 might not be playable, but what about 720x404?.

720x400 will work for sure, since it's divisible by 16 and has square pixels (save for some very old Divx players that won't play videos with a width more than 640 pixels). I have also seen this resolution used in the wild and by Divx Inc's own converter tools.

But both 720x404 and 720x400 require a resize, and the whole point of anamorphic for 720x480 is to not resize.

Originally Posted by yukichigai

EDIT: might also be limited to multiples of 8 or multiples of 16. That used to be a thing.

Divx players may expect a resolution that's divisible by 16, have you tried with the width forced to 848 instead of 852?

Of course, there is always the case of the player refusing to play a video with a forced width over 720, in which case, ol' reliable MPEG4 Modifier is the only way to get 720x480 anamorphic widescreen for some players (players with ESS Vibrato chip won't honor the anamorphic flag though, your only option is to set the player to 4:3 output mode and stretch to 16:9 using the TV).

[SeeMoreDigital]

Adding aspect ratio signalling to MPEG-4 SP/ASP video streams is nothing new. Indeed quite a few players and more importantly their AV decoding chip-set, supported this feature some twenty years ago!

The stickies within this section of the forum contains some information on some of the supporting AV decoding chip-sets...

[kurkosdr]

Originally Posted by SeeMoreDigital

Adding aspect ratio signalling to MPEG-4 SP/ASP video streams is nothing new. Indeed quite a few players and more importantly their AV decoding chip-set, supported this feature some twenty years ago!

The stickies within this section of the forum contains some information on some of the supporting AV decoding chip-sets...

Yes, that's why I called MPEG4 Modifier "ol' reliable", it's nothing new. But as I said above, support for anamorphic Divx avi files is hit and miss in standalone players (so, even if the flag has been set correctly using MPEG4 Modifier, you may not get anamorphic), that's why I hope forced width to 848x480 or 1024x576 works as an alternative method of signalling anamorphic.

[yukichigai]

Originally Posted by kurkosdr

Interesting... does it also work for the override that would allow no-resize rips from anamorphic DVDs, that is, 720x480 that should be displayed as 854x480 and 720x576 that should be displayed as 1024x576?

I had some limited success with Mpeg4 Modifier, but only on later-model players. Maybe this hack will work? Can you try on your player?

Originally Posted by kurkosdr

Yes, that's why I called MPEG4 Modifier "ol' reliable", it's nothing new. But as I said above, support for anamorphic Divx avi files is hit and miss in standalone players (so, even if the flag has been set correctly using MPEG4 Modifier, you may not get anamorphic), that's why I hope forced width to 848x480 or 1024x576 works as an alternative method of signalling anamorphic.

Alright, I managed to find a cheap universal remote that works for my player (awkwardly) so testing went a lot faster.

Short version: the 3390 won't play anything with a width of more than 720. This includes the values in overridden AVI tags. I tried the same file with a variety of size overrides and the only ones that wouldn't play were ones where the tag-specified width exceeded 720. I had no problems playing files with the size overridden to 640x352, 640x360, 720x400, 720x404, and (non-overridden) 720x480. 848x480, 852x480, and 854x480 all failed to play.

Now I haven't tested height limits, nor have I tested if higher res content can be "soft-downscaled" using AVI tag overrides and be made playable without re-encoding. In general though I'm guessing that 720x576 is the resolution limit you need to work within for this player when overriding width and height using AVI tags.

EDIT: Oh yeah, I wanted to add that this method has the advantage(?) of being ignored by VLC, Media Player Classic, and MPV, while the 3390 ignores all AR overrides EXCEPT the AVI tags. The same file will render at 853x480 on my computer and 720x404 on the 3390. This seems to be a good way to force compatibility on older hardware without negatively impacting playback on more advanced devices.

[SeeMoreDigital]

Just so everyone knows...

You should not generate encodes using any more than 414,720 pixels, which is the maximum number of pixels most AV decoding chip-sets in these old players can handle...

So in some cases it's possible to generate 'square pixel' encodes using 864x480 pixels at 23.976/24.000fps!

EDIT 1: It should also be noted that not all players that supported MPEG-4 SP/ASP video playback also supported aspect ratio signalling for MPEG-4 SP/ASP video.

EDIT 2: All the early MPEG-4 in .avi hardware players I tested that supported aspect ratio signaling, were able to do it at the 'video stream' level only. Later players that carried Nero Digital certification supported aspect ratio signaling at the 'video stream' level and at the .mp4 'container level'.

[v0lt]

You didn't explain what exactly you are changing.

The "strf" block stores the "BITMAPINFOHEADER" structure. It contains the biWidth and biHeight parameters. I don't recommend changing them, otherwise you will get corrupted files that will cause problems during playback.

There are also the biXPelsPerMeter and biYPelsPerMeter parameters. It looks very similar to what you need, but as a rule it doesn't work. I have never seen it used anywhere.

Therefore, we are left with the only option to write the frame proportions into the stream using MPEG4 Modifier. And this works well with many players. For some old DVD players, you need to update the firmware.

PS: Some DVD players can play the old non-standard OGM format (hacked OGG).

PPS: There is no point in doing all this with AVI now, when there are many inexpensive players that play MP4 and MKV.

[yukichigai]

Originally Posted by v0lt

You didn't explain what exactly you are changing.

The "strf" block stores the "BITMAPINFOHEADER" structure. It contains the biWidth and biHeight parameters. I don't recommend changing them, otherwise you will get corrupted files that will cause problems during playback.

I am indeed overriding biWidth and biHeight, along with dwWidth and dwHeight in the avih 56 header block. As I said previously, I've encountered no issues with playback when doing this: no corruption, no issues fast forwarding or rewinding, no desyncing. The files play just fine, both in the DVD player and on my computer.

Originally Posted by v0lt

Therefore, we are left with the only option to write the frame proportions into the stream using MPEG4 Modifier. And this works well with many players. For some old DVD players, you need to update the firmware.

Like I said, that doesn't work for this player. There are no firmware updates available for it either.

Originally Posted by v0lt

PPS: There is no point in doing all this with AVI now, when there are many inexpensive players that play MP4 and MKV.

There is: this is the unit I have available for the use case I need it for.

There's also the most important reason: because I can.

[kurkosdr]

Originally Posted by v0lt

Therefore, we are left with the only option to write the frame proportions into the stream using MPEG4 Modifier. And this works well with many players. For some old DVD players, you need to update the firmware.

Players with ESS Vibratto SoCs never got an update enabling anamorphic. Generally, most DVD players didn't receive firmware updates unless there was a disaster going on. The idea of standalone devices needing software updates didn't emerge until Blu-ray and its multiple revisions of BD+ emerged.

Originally Posted by v0lt

PPS: There is no point in doing all this with AVI now, when there are many inexpensive players that play MP4 and MKV.

DVD players are still present in car players, since Blu-ray never reached cars (and the need for constant firmware updates to BD+ probably had something to do with it). Also, the vast majority of DVD players do not do H.264 (since it's considered an "HD format"), they only do DVD-Video and Divx, so, if you want things to play on your car DVD player, it's either DVD-Video or Divx.

[SeeMoreDigital]

Originally Posted by kurkosdr

Players with ESS Vibratto SoCs never got an update enabling anamorphic. Generally, most DVD players didn't receive firmware updates unless there was a disaster going on. The idea of standalone devices needing software updates didn't emerge until Blu-ray and its multiple revisions of BD+ emerged.

That's not entirely true. I tested many early MPEG-4 SP/ASP in .avi only players that supported aspect ratio signalling at the 'video stream' level...

[kurkosdr]

Originally Posted by SeeMoreDigital

That's not entirely true. I tested many early MPEG-4 SP/ASP in .avi only players that supported aspect ratio signalling at the 'video stream' level...

Yes, because they don't use an ESS Vibratto SoC but some other SoC. When it comes to Divx players that don't support anamorphic, it's unlikely a firmware update exists to update them.

[SeeMoreDigital]

Originally Posted by kurkosdr

When it comes to Divx players that don't support anamorphic, it's unlikely a firmware update exists to update them.

I tested many players with DivX logos on them and many supported aspect ratio signalling. I even had a pre-production unit sent to me from DivX themselves, that sadly never launched.

Here's some information regarding players fitted with ESS AV decoding chip-sets. Agreed, their chip-sets were less featured than other AV decoding chip-sets!

[yukichigai]

Originally Posted by kurkosdr

DVD players are still present in car players, since Blu-ray never reached cars (and the need for constant firmware updates to BD+ probably had something to do with it). Also, the vast majority of DVD players do not do H.264 (since it's considered an "HD format"), they only do DVD-Video and Divx, so, if you want things to play on your car DVD player, it's either DVD-Video or Divx.

The particular use case I have is getting something that outputs to NTSC analog RF at 4:3 aspect ratio. AFAIK nothing past the DVD era outputs direct to RF, and as it is most DVD players don't either. Even if I wanted to use an RF modulator it's rare to find any newer hardware media player that doesn't output to HDMI, much less will output at 480i/p, and forget 4:3 output.

In other words I could spend $30 on an RF modulator to produce a downsampled signal of upsampled playback of video that isn't even played at the right aspect ratio... or I could dust off the ol' DivX-certified player. Not a hard choice.

[v0lt]

Originally Posted by kurkosdr

Generally, most DVD players didn't receive firmware updates unless there was a disaster going on.

I know for sure that there were updated firmware and modified firmware for Pioneer and BBK. Official firmware could also be found for many DVD players. Here I agree that not all manufacturers updated them.

DVD players are still present in car players

I doubt they are still used for their intended purpose. I think it would be easier for passengers to use a tablet.

[yukichigai]

Originally Posted by v0lt

I doubt they are still used for their intended purpose. I think it would be easier for passengers to use a tablet.

It's a lot easier to put on one thing that all the kids in the back of the car can watch than expecting all of them to politely and considerately make sure everyone can view the tablet that one of them is holding. A lot harder for them to break the thing too, usually.

Also they're generally placed so passengers can see out the windows in their peripheral vision, which minimizes the risk of motion sickness. Having a kid staring down at something is a great recipe to go from "yay Spongebob" to "Uncle I think I got your tablet messy" in under 5 seconds.