[FFmpeg-devel] Problems with current GIT version

JULIAN GARDNER joolzg at btinternet.com
Tue Oct 9 16:30:41 CEST 2012

Ive been trying to get this resolved on the user mailing list, mainly with Carl, but for some reason my mail needs authorisation and it takes over a day to get 1 email into the list.

This is the message i posted a week ago!

Just upgraded to latest git and im getting a problem i never had before.

Im transcoding Channel4HD down to a lower rate but every now and then it stops sending data

On start
2012-10-03_20:22:38.04839 [mpegts @ 0x2a10340] Estimating duration from bitrate, this may be inaccurate
2012-10-03_20:22:38.04849 Input #0, mpegts, from 'udp://':
2012-10-03_20:22:38.04850   Duration: N/A, start: 35407.144378, bitrate: 576 kb/s
2012-10-03_20:22:38.04850   Program 21200 
2012-10-03_20:22:38.04851     Metadata:
2012-10-03_20:22:38.04851       service_name    : Channel 4 HD
2012-10-03_20:22:38.04851       service_provider: BSkyB
 Stream #0:0[0x901]: Video: h264 (Main) ([27][0][0][0] / 0x001B), 
yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 54.33 fps, 50 tbr, 90k tbn, 50 
2012-10-03_20:22:38.04853     Stream #0:1[0x903](NAR): Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, s16, 192 kb/s
2012-10-03_20:22:38.04854     Stream #0:2[0x905](eng): Subtitle: dvb_teletext ([6][0][0][0] / 0x0006)
2012-10-03_20:22:38.04855     Stream #0:3[0x904](eng): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)
2012-10-03_20:22:38.04856     Stream #0:4[0x902](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, s16, 384 kb/s

We then encode with no problems, but then this happens

Input stream #0:4 frame changed from rate:48000 fmt:s16 ch:2 chl:stereo to rate:48000 fmt:s16 ch:6 chl:5.1(side)
2012-10-03_22:22:20.36222 -async is forwarded to lavfi similarly to -af aresample=min_comp=0.001:min_hard_comp=0.100000.
2012-10-03_22:22:20.80007 [libfaac @ 0x24afee0] Que input is backward in time
 frame= 5539 fps= 26 q=24.0 size=   32837kB time=00:03:40.64 
bitrate=1219.2kbits/s dup=49 drop=0    ^Mst:0 PTS: 0 DTS: 0 < 
19860481 invalid, clipping
2012-10-03_22:22:20.85381 [mpegts @ 0x2b0b160] st:0 PTS: 2880 DTS: 2880 < 19860482 invalid, clipping
2012-10-03_22:22:20.85431 [mpegts  @ 0x2b0b160] st:0 PTS: 5760 DTS: 5760 < 19860483 invalid, clipping
2012-10-03_22:22:20.85448 [mpegts @ 0x2b0b160] st:0 PTS: 8640 DTS: 8640 < 19860484 invalid, clipping
(then the above line is repeated ad inifitum)

A copy of the ts is here (93MB) http://joolzg.myetrayz.net:8080/rapidbox/rapidFileDownload.php?r_id=c9f0f895fb98ab9159f51fd0297e236d

At around the 1minute mark it switches audio and ffmpeg goes crazy

command line
 -i ../fails.bin -vcodec libx264 -b:v 1500k -preset faster -s 720x576 
-acodec libfaac -b:a 128k -ar 32k -ac 2 -async 1 -map 0:0 -map 0:4 -f 
mpegts -y a.ts

Carl asked for a complete log of the output but as everything is ok up to the failure and all that happens is the last message is repeated from then on.

I did find that removing "-async 1" makes the error go away, but then we would not have audio/video sync.


More information about the ffmpeg-devel mailing list