[mythtv-users] BBC HD recorded show length wrong in mythfrontend

[belcampo]

David Knight wrote:
> On Sat, September 12, 2009 10:14 am, Robert wrote:
>> Hi all,
>>
>> It seems that my BBC HD recordings are reporting incorrect lengths again
>> in mythtv.  (straight record and then playback in mythfrontend).
>>
>> I recorded a 30 min show last night and when I went to play it, it said
>> it was an hour.  As it played, time passed as normal - i.e. after 30
>> mins actual time, 30 mins had passed on the progress bar and the
>> programme was over.  But when I went to seek in the recording I had to
>> seek to (eg) 40mins on the progress bar to get 20 mins into the show.
See bottom.
>>
>> I've had this before (ages ago) and I think there was a patch to fix it
>> and it's been fine for a long time now.
>>
>> Is anyone seeing this?  or is it just me?
>>
>> I noticed in another sillyname's thread about transcoding that they've
>> recently changed something in the format and was wondering if this might
>> be the cause.
>>
>> Other than that I recently recompiled my whole system (gentoo) and I'm
>> wondering if that has broken something.
>>
>> Any ideas where to start looking?
>>
>> Thanks,
>> Robert.
>>
>>
> 
> Hi Robert/BBC HD Viewers,
> 
>     Not sure if I replied before but I'm fed up of recordings finishing
> early. I've also noticed quite a bit of image artifacts watching BBC
> HD lately and general compression nasties. So I did a bit of googling
> and managed to trawl up quite a number of blog/forum threads relating
> to poor image quality lately on BBC HD.
> 
> Here is some information on what is going on directly from the head of BBC
> HD -
> http://www.bbc.co.uk/blogs/bbcinternet/2009/09/picture_quality_on_hd_a_respon.html
> 
> It appears that the BBC are now using new encoders (apologies I haven't
> read the post about encoding or don't recall it). They may also have
> dropped the bitrate from 16Mpbs to 9Mbps!!! almost halving it.
If a newer encoder is more efficient, they can lower the bitrate for the 
same quality. As bzip2 has options --fast and --best, for lower/higher 
compression, where decoding results in the same file.

Here 
http://compression.ru/video/codec_comparison/mpeg-4_avc_h264_2005_en.html
one can read that some encoders are much more efficient than others for 
the same quality.
> 
> I also used to be able to watch the recordings on my Windows PC through
> Mythweb asx stream but that doesn't work anymore (guessing this is the
> encoder change) Windows Media Player reports that the codec is unknown.
The installed software is to blame. Hardware encoders working according 
  to the h264 specs work without a problem.
> 
> I'm pretty angry about this, the BBC are backing up what they have done by
> saying that they need to reduce the amount of bandwidth they are utilising
> and also maintain compatibility with set top boxes.
> 
> I originally started watching BBC HD in September last year and understand
> it was originally being broadcast then at 20Mbps, which dropped to 16Mbps
> earlier this year.
> 
> I have made my complaint and asked if the BBC has any plans to rename the
> channel to BBC SD ! :)
> 
> Regards
> 
> Dave K.
> 
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A month ago I wrote this on the ffmpeg-user list

BBCHD fps mis-interpretation

It seems BBCHD streams from DVB-S have changed, it always was MBAFF 
interlaced, now it is interpreted as 50fps
Stream #0.0[0x157c]: Video: h264, yuv420p, 1440x1080 [PAR 4:3 DAR 16:9], 
50 tbr, 90k tbn, 50 tbc

Although mediainfo for the same file says:

Frame rate                       : 25.000
Frame rate                       : 25.000 fps
Frame count                      : 97582
Resolution                       : 24
Resolution                       : 24 bits
Colorimetry                      : 4:2:0
Scan type                        : Interlaced
Scan type                        : Interlaced
Scan order                       : TFF
Scan order                       : Top Field First
Interlacement                    : TFF