Re: can -c be made to seek?

David Liontooth wrote:
> Hi Carl,
> 
> Carl Karsten wrote:
>> In trying to grab a frame every 30 seconds (or every 900 frames - 
>> close enough)  I see tc spending time 'skipping frames' - any way to 
>> get it to seek ahead some number of bytes or something?  (close, even 
>> for wide values of close, would be fine)
> I switched to -c because I needed split-second accuracy, but if you 
> don't, try --frame_interval. It may even be frame-accurate now.
> 
> transcode -q 0 -o $DDIR/$FIL.img -y im -F png -x ffmpeg,null -i 
> $DDIR/$FIL.dv --frame_interval 900 2> /dev/null
> 
> If you try, let us know what performance you get.

No help on performance, but the command line is much easier to construct.

juser@pycon08a:~/temp/pycon$ ./y.sh
++ rm img/x000000.png img/x000001.png img/x000002.png img/x000003.png
++ INFIL='clip-2008-03-15 11;07;38.dv'
++ OUTFIL=x
++ transcode -Q 0 -i 'clip-2008-03-15 11;07;38.dv' -x dv,null -o img/x -y im -F 
png --frame_interval 900 -c 0-17101
transcode v1.2.0-cvs (C) 2001-2003 Thomas Oestreich, 2003-2007 Transcode Team
[transcode] V: auto-probing     | clip-2008-03-15 11;07;38.dv (OK)
[transcode] V: import format    | DigitalVideo in NTSC (module=dv)
[transcode] A: auto-probing     | clip-2008-03-15 11;07;38.dv (OK)
[transcode] A: import format    | PCM in NTSC (module=null)
[transcode] V: AV demux/sync    | (1) sync AV at initial MPEG sequence
[transcode] V: import frame     | 720x480  1.50:1  encoded @ 4:3
[transcode] V: bits/pixel       | 0.174
[transcode] V: decoding fps,frc | 29.970,4
[transcode] V: video format     | YUV420 (4:2:0) aka I420
[transcode] A: import format    | 0x1     PCM          [48000,16,2] 1536 kbps
[transcode] A: export format    | 0x55    MPEG ES Layer 3 [48000,16,2]  128 kbps
[transcode] V: export format    | unknown (module dependant)
[transcode] V: encoding fps,frc | 29.970,4
[transcode] A: bytes per frame  | 6408 (6406.400000)
[transcode] A: adjustment       | -1600@1000
[transcode] V: IA32/AMD64 accel | sse3 sse2 sse 3dnowext 3dnow mmxext mmx cmove asm
[transcode] V: video buffer     | 10 @ 720x480 [0x2]
[transcode] A: audio buffer     | 10 @ 48000x2x16
[import_null.so] v0.2.0 (2002-01-19) (video) null | (audio) null
[import_dv.so] v0.3.1 (2003-10-14) (video) DV | (audio) PCM
[export_im.so] v0.0.4 (2003-11-13) (video) *
[import_dv.so] tcextract -x dv -i "clip-2008-03-15 11;07;38.dv" -d 0 | tcdecode 
-x dv -y yuv420p -d 0 -Q 5
encoding frame [17100/17101],  27.24 fps, 100.0%, ETA: 0:00:00, ( 0| 0|20)
[transcode] encoded 17101 frames (0 dropped, 0 cloned), clip length 570.60 s

real    10m29.882s
user    9m27.215s
sys     1m1.984s
++ ls -l img
total 29980juser@pycon08a:~/temp/pycon$ ./y.sh
++ rm img/x000000.png img/x000001.png img/x000002.png img/x000003.png
++ INFIL='clip-2008-03-15 11;07;38.dv'
++ OUTFIL=x
++ transcode -Q 0 -i 'clip-2008-03-15 11;07;38.dv' -x dv,null -o img/x -y im -F 
png --frame_interval 900 -c 0-17101
transcode v1.2.0-cvs (C) 2001-2003 Thomas Oestreich, 2003-2007 Transcode Team
[transcode] V: auto-probing     | clip-2008-03-15 11;07;38.dv (OK)
[transcode] V: import format    | DigitalVideo in NTSC (module=dv)
[transcode] A: auto-probing     | clip-2008-03-15 11;07;38.dv (OK)
[transcode] A: import format    | PCM in NTSC (module=null)
[transcode] V: AV demux/sync    | (1) sync AV at initial MPEG sequence
[transcode] V: import frame     | 720x480  1.50:1  encoded @ 4:3
[transcode] V: bits/pixel       | 0.174
[transcode] V: decoding fps,frc | 29.970,4
[transcode] V: video format     | YUV420 (4:2:0) aka I420
[transcode] A: import format    | 0x1     PCM          [48000,16,2] 1536 kbps
[transcode] A: export format    | 0x55    MPEG ES Layer 3 [48000,16,2]  128 kbps
[transcode] V: export format    | unknown (module dependant)
[transcode] V: encoding fps,frc | 29.970,4
[transcode] A: bytes per frame  | 6408 (6406.400000)
[transcode] A: adjustment       | -1600@1000
[transcode] V: IA32/AMD64 accel | sse3 sse2 sse 3dnowext 3dnow mmxext mmx cmove asm
[transcode] V: video buffer     | 10 @ 720x480 [0x2]
[transcode] A: audio buffer     | 10 @ 48000x2x16
[import_null.so] v0.2.0 (2002-01-19) (video) null | (audio) null
[import_dv.so] v0.3.1 (2003-10-14) (video) DV | (audio) PCM
[export_im.so] v0.0.4 (2003-11-13) (video) *
[import_dv.so] tcextract -x dv -i "clip-2008-03-15 11;07;38.dv" -d 0 | tcdecode 
-x dv -y yuv420p -d 0 -Q 5
encoding frame [17100/17101],  27.24 fps, 100.0%, ETA: 0:00:00, ( 0| 0|20)
[transcode] encoded 17101 frames (0 dropped, 0 cloned), clip length 570.60 s

real    10m29.882s
user    9m27.215s
sys     1m1.984s
++ ls -l img
total 29980
...
-rw-r--r-- 1 juser juser 800575 2008-04-17 13:31 x000038.png

I was afraid it created 17101 .pngs

Carl K