[ivtv-users] Capturing streams without B-Frames

[Alexander Pipelka]

Am Di 21.10.2008 08:27 schrieb Hans Verkuil <hverkuil at xs4all.nl>:

> Can you run this test for me using the v4l-dvb repository?
> 
> As root:
> 
> rmmod ivtv
> modprobe ivtv
> 
> As a normal user:
> 
> v4l2-ctl -f <freq>
> 
> (freq in MHz; note that you can readback the selected frequency using 
> v4l2-ctl -F)
> 
> v4l2-ctl -c video_b_frames=0
> cat /dev/video0 >test.mpg
> 
> Now run in another shell:
> 
> v4l2-ctl --log-status
> 
> Break off the 'cat' command, check that test.mpg is indeed still 0
> bytes
> and post the output of the v4l2-ctl --log-status command.

Ok. Here we go (I didn't set the frequency because I'm capturing from a
S-Video source):

[ 297.706759] ivtv0: ================= START STATUS CARD #0
   =================
   [  297.706780] ivtv0: Version: 1.4.0 Card: Yuan MPC622
   [  297.709794] cx25840 0-0044: Video signal:              present
   [  297.709799] cx25840 0-0044: Detected format:           PAL-BDGHI
   [  297.709802] cx25840 0-0044: Specified standard:        PAL-BDGHI
[ 297.709805] cx25840 0-0044: Specified video input: S-Video (Luma In3,
   Chroma In4)
   [  297.709809] cx25840 0-0044: Specified audioclock freq: 48000 Hz
   [  297.720934] cx25840 0-0044: Detected audio mode:       mono
[ 297.720947] cx25840 0-0044: Detected audio standard: no detected audio
   standard
   [  297.720951] cx25840 0-0044: Audio muted:               no
   [  297.720955] cx25840 0-0044: Audio microcontroller:     stopped
[ 297.720958] cx25840 0-0044: Configured audio standard: automatic
   detection
[ 297.720962] cx25840 0-0044: Configured audio system: automatic
   standard and mode detection
   [  297.720965] cx25840 0-0044: Specified audio input:     External
   [  297.720969] cx25840 0-0044: Preferred audio mode:      stereo
   [  297.720971] cx25840 0-0044: Selected 65 MHz format:    autodetect
   [  297.720974] cx25840 0-0044: Selected 45 MHz format:    chroma
   [  297.722529] ivtv0: Video Input:  S-Video 1
   [  297.722534] ivtv0: Audio Input:  Line In 1
   [  297.722536] ivtv0: Tuner:  TV
   [  297.722540] ivtv0: Stream: MPEG-2 Program Stream
   [  297.722544] ivtv0: VBI Format: No VBI
   [  297.722547] ivtv0: Video:  720x576, 25 fps
[ 297.722550] ivtv0: Video: MPEG-2, 4x3, Variable Bitrate, 6000000, Peak
   8000000
   [  297.722555] ivtv0: Video:  GOP Size 15, 0 B-Frames, GOP Closure
[ 297.722559] ivtv0: Audio: 48 kHz, MPEG-1/2 Layer II, 224 kbps, Stereo,
   No Emphasis, No CRC
[ 297.722564] ivtv0: Spatial Filter: Manual, Luma 1D Horizontal, Chroma
   1D Horizontal, 0
   [  297.722567] ivtv0: Temporal Filter: Manual, 8
[ 297.722570] ivtv0: Median Filter: Off, Luma [0, 255], Chroma [0, 255]
   [  297.722573] ivtv0: Status flags:    0x00200000
[ 297.722578] ivtv0: Stream encoder MPG: status 0x0118, 0% of 4096 KiB
   (128 buffers) in use
[ 297.722582] ivtv0: Stream encoder YUV: status 0x0000, 0% of 8192 KiB
   (256 buffers) in use
[ 297.722586] ivtv0: Stream encoder VBI: status 0x0000, 0% of 1040 KiB
   (61 buffers) in use
[ 297.722590] ivtv0: Stream encoder PCM: status 0x0000, 0% of 324 KiB
   (72 buffers) in use
   [  297.722593] ivtv0: Read MPG/VBI: 0/0 bytes
[ 297.722595] ivtv0: ================== END STATUS CARD #0
   ==================

test.mpg is as expected indeed 0 bytes.


Regards, 

Alex