[mythtv-users] Interlace x2 perfect with 4:3 videos, but can't use fill function with 16:9 content

Thu Jan 21 17:34:43 UTC 2010

Hi,
I'm using mythbuntu since 2 years. Everything is working well and i have recently upgraded to the last version (mythbuntu 9.10 with myth 0.22)

During the upgrade from the previous version I discovered that now it is possibile to feed a television with a correct interlaced signal and achieve a nearly perfect quality with Interlaced x2 "deinterlacer". ( http://svn.mythtv.org/trac/ticket/6391 ) 

So I searched my old VGAtoRGB SCART circuit and tested some modeline for my old 4:3 100 Hz CRT Television and finally i found "my modeline" and now i achieve an excellent quality when watching video in 4:3.

But I have an issue. 

When I watch video in 16:9 mythtv automatically set the display size 768 x 432 (when the native resolution is 756 x 576) and this, obviously, breaks the deinterlacer "Interlace x2". 

I found a compromise using the zoom functionality that, setted to "full", removes any interlace problem when playing 16:9, but it is necessary to specify this function every time the show changes. (In my country broadcasters don't use a fixed Aspect Ratio, which changes for every transmission). 

Indeed the auto detect zoom function (auto detect letter box) doesn't  work with Interlaced 2x and 4:3 television. It seems that auto zoom / detect letter box with interlaced 2x assumes a television target of 16:9

2010-01-21 18:10:52.077 VDP: SetVideoRenderer(xv-blit)
2010-01-21 18:10:52.077 VDP: SetVideoRender(xv-blit) == GetVideoRenderer()
2010-01-21 18:10:52.078 VideoOutputXv: PictureAttributes:
2010-01-21 18:10:52.078 VideoOutputXv: Chromakeying not possible with this XVideo port.

2010-01-21 18:10:52.078 Display Rect  left: 0, top: 72, width: 768, height: 432, aspect: 1.33333
2010-01-21 18:10:52.079 Video Rect    left: 0, top: 0, width: 720, height: 576, aspect: 1.77778

2010-01-21 18:10:52.240 NVP(3): ClearAfterSeek(1)
2010-01-21 18:10:52.240 VideoOutputXv: ClearAfterSeek()
2010-01-21 18:10:52.240 VideoOutputXv: DiscardFrames(0)
2010-01-21 18:10:52.240 VideoBuffers::DiscardFrames(0): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
2010-01-21 18:10:52.240 VideoBuffers::DiscardFrames(0): AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done
2010-01-21 18:10:52.240 VideoOutputXv: DiscardFrames() 3: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA -- done()
2010-01-21 18:10:52.245 NVP(3): LoadFilters(''..) -> 0x0
2010-01-21 18:10:52.245 detectInterlace(Detect Scan, Interlaced Scan, 25, 576) ->Interlaced Scan
2010-01-21 18:10:52.245 AFD: Using ffmpeg for video decoding
2010-01-21 18:10:52.245 AFD: Looking for decoder for MPEG2VIDEO
2010-01-21 18:10:52.245 AFD: Opened codec 0xb5dffb0, id(MPEG2VIDEO) type(Video)
2010-01-21 18:10:52.245 AFD: Stream #1, has id 0x7a codec id MP2, type Audio, bitrate 192000 at 0xaaac710
2010-01-21 18:10:52.245 AFD: codec MP2 has 2 channels
2010-01-21 18:10:52.245 AFD: Looking for decoder for MP2
2010-01-21 18:10:52.245 AFD: Opened codec 0xb5dbd90, id(MP2) type(Audio)
2010-01-21 18:10:52.245 AFD: Stream #2, has id 0x7b codec id MP2, type Audio, bitrate 80000 at 0xb6166d0
2010-01-21 18:10:52.245 AFD: codec MP2 has 1 channels
2010-01-21 18:10:52.245 AFD: Looking for decoder for MP2
2010-01-21 18:10:52.246 AFD: Opened codec 0xb82a790, id(MP2) type(Audio)
2010-01-21 18:10:52.246 AFD: Stream #3, has id 0x49 codec id DVB_VBI, type Data, bitrate 0 at 0xb41dad0
2010-01-21 18:10:52.246 AFD: Teletext caption #1 is in the French language on page 7 119.
2010-01-21 18:10:52.246 AFD: data codec (Data)
2010-01-21 18:10:52.333 RingBuf(/mythtv/recordings/13257_20100121181050.mpg): CalcReadAheadThresh(0 KB)
                         -> threshhold(64 KB) min read(0 KB) blk size(32 KB)
2010-01-21 18:10:52.337 Opening audio device 'surround51'. ch 2(1) sr 48000
2010-01-21 18:10:52.337 Opening ALSA audio device 'surround51'.
2010-01-21 18:10:52.451 mixer unable to find control Master 1
2010-01-21 18:10:52.452 NVP(3): Enabling Audio
2010-01-21 18:10:52.452 Dec: Trying to select track (w/lang)
2010-01-21 18:10:52.463 Dec: Selecting first track
2010-01-21 18:10:52.463 Dec: Selected track #1 in the Unknown language(0)
2010-01-21 18:10:52.463 Dec: Selected track #1 in the French language(6713957)
2010-01-21 18:10:52.463 Dec: Resyncing position map. posmapStarted = 0 livetv(1) watchingRec(1)
2010-01-21 18:10:52.464 Position map filled from DB to: 12
2010-01-21 18:10:52.464 Dec: SyncPositionMap watchingrecording, from DB: 2 entries
2010-01-21 18:10:52.464 NVP(3): Filling position map from 13 to end
2010-01-21 18:10:52.482 Dec: Position map filled from Encoder to: 36
2010-01-21 18:10:52.482 Dec: SyncPositionMap watchingrecording total: 4 entries
2010-01-21 18:10:52.482 Dec: SyncPositionMap, new totframes: 36, new length: 1, posMap size: 4
2010-01-21 18:10:52.493 AFD: Partial position map found
2010-01-21 18:10:52.493 AFD: Successfully opened decoder for file: "/mythtv/recordings/13257_20100121181050.mpg". novideo(0)
2010-01-21 18:10:52.495 NVP(3): DoPlay() -- begin
2010-01-21 18:10:52.495 NVP(3): DoPlay: rate: 25 speed: 1 skip: 1 => new interval 40000
2010-01-21 18:10:52.495 Set video sync frame interval to 40000
2010-01-21 18:10:52.495 NVP(3): Stretch Factor 1, allow passthru
2010-01-21 18:10:52.495 NVP(3): DoPlay() -- setting unpaused
2010-01-21 18:10:52.504 NVP(3): Waiting for prebuffer..  0 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
2010-01-21 18:10:52.515 RingBuf(/mythtv/recordings/13257_20100121181050.mpg): CalcReadAheadThresh(0 KB)
                         -> threshhold(64 KB) min read(0 KB) blk size(32 KB)
2010-01-21 18:10:52.515 Dec: Resyncing position map. posmapStarted = 0 livetv(1) watchingRec(1)
2010-01-21 18:10:52.515 Position map filled from DB to: 12
2010-01-21 18:10:52.516 Dec: SyncPositionMap watchingrecording, from DB: 2 entries
2010-01-21 18:10:52.516 NVP(3): Filling position map from 13 to end
2010-01-21 18:10:52.518 Dec: Position map filled from Encoder to: 36
2010-01-21 18:10:52.518 Dec: SyncPositionMap watchingrecording total: 4 entries
2010-01-21 18:10:52.525 Detect Letterbox: YV12 frame format detected

2010-01-21 18:10:52.526 Detect Letterbox: The source is already in widescreen (aspect: 1.77778)

'video_output' mean = '39955.40', std. dev. = '534.71', fps = '25.03'
'video_output' mean = '39955.31', std. dev. = '375.15', fps = '25.03'

The old mythtv 0.20 had a special function to manage this situation which still is documented here :

http://www.mythtv.org/wiki/User_Manual:Detailed_configuration_Frontend

General Playback, 7th line.

I Can use the zoom full function while watching the television, but I can't find any way to display automatically the video without interlace issue.

I was thinking also to use a different playback profile when watching a 16:9 video, but i can't discriminate videos by aspect ratio when configuring playback profile.

Thank for your attention and any help :)

Tommaso