Choppy playback of HDTV to AVCHD

[Dr_Layne]

OK here's what I've done. Using the firewire port on my Motorola DTC 6412 and DVHSCap, I grabbed about 10 mins of HDTV programming. The resulting file plays flawlessly in VLC. When I convert the file to AVCHD DVD specs using any of the following tools; MKV2VOB, TsMuxer, and MultiAVCHD, the results are choppy video with out of sync audio on both the HDD of the PC and if I burn to a BD spec DVD (UDF 2.50) on my Sony BDP-S550.

Not sure why the AVCHD conversion is resulting in choppy playback on the PC when the original file plays smooth.

File is MPEG2 with AC3 5.1 audio in a .ts container.

A_L

[wibo.video]

Hello Doctor,

I too have the same Sony BD player. I bought a Sony BD, as I was a long time, fairly satisfied customer. I chose the 550 model over the 350 model largely because it was made in Japan, instead of in a third world factory as the 350 model was.

You refer to a capture of HDTV content. Do you know if this was ORIGINALLY in mpeg2 format? (probaly was...). If so, according to the BD format specs, you shouldn't have to transcode into ACVHD at all, a far more compressed format that's good with quiet scenes, but breaks down quickly in fast moving action.

I ask this because you refer to the disk as ACVHD and that "...the File is MPEG2 with AC3 5.1 audio in a .ts container. " These two statements can't both be true as ACVHD is not mpeg2.

I have a similar issue as you, as I bought a Sony HDV camcorder, the HC7, and burnt a DVD5 with mpeg2 content from my camcorder that was fully compliant with the BD spec (had to transcode the audio, not the video, which I wanted in it's pristine, non-transcoded version). My DVD plays, but "hiccups" irregularly, approx every 3 seconds.

It is not as if the bit streaming is very extreme, as it is at 24-25 Mbits/s, similar to many BD or DVD commercial disks. The player's processor would presumably have a lot less to do as compared to ACVHD content (8-15 Mbits/s, approx), a lot more compressed, therefore more processor-dependent to decompress.

I also thought Sony's higher-than-entry-level product would be fully BD spec compliant, and at least as versatile as the PS3 for BD compliant content. I would also have thought that Sony BD would playback a fully compliant mpeg2 DVD but alas, it plays back very choppy like you describe.

I have the latest flash update. I asked SONY through online help about this issue, but the answer received was totally unresponsive to my detailed questions (even offered them to send them the DVD). I'm very disappointed with Sony.

Apparently the Panasonic BD player equivalent to the 550 model apparently plays these disks flawlessly and the PS3 plays such mpeg2 content dumped on it's hard disk.

Curiously, when I tested the same footage, actually transcoded in ACVHD and burnt on a DVD mine plays flawlessly in my 550. The transcoding into ACVHD format is a step I do not wish to have to take on a regular basis, because 1.) it takes time and considerable computer resources and mostly because 2.) I'm loosing quality.

If you like, I can look up the process I used and let you know: it's late and I can't find it right now.

What I ultimately want want, is for Sony to post a flash update to cure this problem on this relatively high-end machine.


Wibo (frustrated...)

[johns0]

Just import the ts file into multiavchd,no need to run it thru mkv2vob,that might be why its getting choppy.

[Dr_Layne]

Just import the ts file into multiavchd,no need to run it thru mkv2vob,that might be why its getting choppy.

I've tried multiavchd same results. Choppy playback even on the PC. Though the original HDTV stream plays flawless on the PC the AVCHD output plays choppy wiht hiccups about every 3 seconds. This is all on the PC playing the files direct form the hard drive.

[johns0]

Can you post a very short clip of about 10 seconds of the stream before its authored?

[johns0]

Curiously, when I tested the same footage, actually transcoded in ACVHD and burnt on a DVD mine plays flawlessly in my 550. The transcoding into ACVHD format is a step I do not wish to have to take on a regular basis, because 1.) it takes time and considerable computer resources and mostly because 2.) I'm loosing quality.


Wibo (frustrated...)

Making an avchd doesnt mean you have to do any encoding,the only reason you would encode is to reduce the bitrate to 18mb/s or less if you burn to dvd,you can import mpeg to avchd and have it play that way as well.

[Dr_Layne]

Can you post a very short clip of about 10 seconds of the stream before its authored?

Ok I edited out a clip using TS Packet Editor.

http://www.webfilehost.com/?mode=viewupload&id=933578

A_L

[wibo.video]

Curiously, when I tested the same footage, actually transcoded in ACVHD and burnt on a DVD mine plays flawlessly in my 550. The transcoding into ACVHD format is a step I do not wish to have to take on a regular basis, because 1.) it takes time and considerable computer resources and mostly because 2.) I'm loosing quality.


Wibo (frustrated...)

Making an avchd doesnt mean you have to do any encoding,the only reason you would encode is to reduce the bitrate to 18mb/s or less if you burn to dvd,you can import mpeg to avchd and have it play that way as well.

I'll tweak that statement if you don't mind. I think you are using AVCHD to refer only to the "container", a Bluray compatible DVD.

There is a tendency to use this technical vocabulary loosely, confusing ACVHD [ "AVCHD is a format for recording and playback of high definition video. Video is compressed in MPEG-4 AVC/H.264 format, and audio is recorded in Dolby Digital. AVCHD and its logo are trademarks of Panasonic corporation and Sony corporation.", according to Wiki ( http://en.wikipedia.org/wiki/AVCHD)]

MPEG-4 (http://en.wikipedia.org/wiki/MPEG-4) is built upon an MPEG-2 foundation, but is not the same as MPEG-2. MPEG-4 is quite a bit more compressed than MPEG-2 format (for a given bitrate, up to approx 4X), but, as in any high compression, it will break down if the picture is too busy. It does do a very good job though.

HDV (most HD "tape" camcorders) and HDTV is "pure" MPEG-2. Not so compressed as MPEG-4, so having the disadvantages of requiring more storage, etc., but somewhat more robust for fast moving content.

Users of Internet sites like one this frequently confuse the video format (as in the compression method) and the container, a DVD containing content compliant with the bluray spec, that can be either ACVHD (MPEG-4 AVC/H.264) or MPEG-2.

The Doctor and I start with MPEG-2 format files and can't get them to play smoothly in our SONY BDP-S550 players.

I have transcoded my MPEG-2 files into AVC/H.264 (ACVHD) and successfully played a DVD5 disk in my BDP-S550 player, showing beautiful HD content.

The Problem is that transcoding takes time and does lose quality. Apparently Panasonic owners do not have this problem and can smoothly play the native ts (MPEG-2) without a hitch. (actually not perfectly "native" ts as the audio has to be demuxed, transcoded and remuxed to come into compliance with the specs, but this is quite quick and easy and it does not affect the pristine quality of the video)

I'm hoping Sony fixes this in an upcoming firmware patch, because otherwise I may have to go over to the dark side (Pannyland).

So, all to say, you are correct in suggesting that IN THEORY one should not have to transcode the MPEG-2 ts, but for us unfortunate dupes, trusting SONY would put together a fine piece of electronics in their upscale bluray player, we don't yet have a choice but to transcode for now.


Wibo, still frustrated.

[johns0]

I had the same problem with the short clip,one way to fix it was to re-encode it,not sure what the problem is but i would think its prolly a sony glitch.

I also used TMPGEnc Authoring Works 4 and it authored the file properly in smart rendering mode and produced a good file with no pausing.Smart rendering means it will only encode parts of the file that is non compliant so most of the video will be untouched and author much faster than re-encoding.

[zoobie]

mpg isn't part of the blu-ray on dvd spec
(although some have gotten it to play on specific players)

[johns0]

Mpeg plays on my sony 350 as avchd-dvdr.

[zoobie]

exactly...

[wibo.video]

mpg isn't part of the blu-ray on dvd spec
(although some have gotten it to play on specific players)

MPEG-2 IS part of the blu-ray on dvd spec, and therefore, SONY's 350 and 550 players that refuse to smoothly play that content are not up to spec:

According to http://www.blu-ray.com/faq/#bluray_formats

"1.8
What video codecs will Blu-ray support?


MPEG-2 - enhanced for HD, also used for playback of DVDs and HDTV recordings.
MPEG-4 AVC - part of the MPEG-4 standard also known as H.264 (High Profile and Main Profile).
SMPTE VC-1 - standard based on Microsoft's Windows Media Video (WMV) technology.

Please note that this simply means that all Blu-ray players and recorders will have to support playback of these video codecs, it will still be up to the movie studios to decide which video codec(s) they use for their releases."



Wibo, still looking for SONY Corp. to update it's firmware...[/url]