[FFmpeg-user] Troubles segmenting WebVTT

[Deron]

I'm trying to capture ATSC with a tuner card and stream it out via HLS. 
I've got it more or less working, and now I would like to try my hand 
and streaming out closed captioning in WebVTT utilizing the eia 608 demuxer.

First, I captured 10 minutes of video to my HD. Then I used:

ffmpeg -f lavfi -i "movie=WPEC.ts[out0+subcc]" -map s WPEC.vtt

which generated a good .vtt file and then

ffmpeg -i WPEC.vtt -f segment -segment_time 10 -segment_format webvtt 
-scodec copy WPEC-%05d.vtt

to generate segments 00000 to 00038 and it works just fine.

However,

ffmpeg -f lavfi -i "movie=WPEC.ts[out0+subcc]" -map s -f segment 
-segment_time 10 -segment_format webvtt WPEC-%05d.vtt

fails to generate segments. What it generates is just one segment named 
WPEC-00000.vtt.

What am I doing wrong?

Deron

Complete uncut output:

# ffmpeg -f lavfi -i "movie=WPEC.ts[out0+subcc]" -map s -f segment 
-segment_time 10 -segment_format webvtt WPEC-%05d.vtt

ffmpeg version N-69558-g7f02fcd Copyright (c) 2000-2015 the FFmpeg 
developers
   built with gcc 4.9.1 (Ubuntu 4.9.1-16ubuntu6)
   configuration: --enable-shared --enable-gpl --enable-nonfree 
--enable-libxvid --enable-libx264 --enable-libmp3lame --enable-libvorbis 
--enable-libfaac --enable-libopenjpeg
   libavutil      54. 18.100 / 54. 18.100
   libavcodec     56. 21.102 / 56. 21.102
   libavformat    56. 19.100 / 56. 19.100
   libavdevice    56.  4.100 / 56.  4.100
   libavfilter     5.  9.103 /  5.  9.103
   libswscale      3.  1.101 /  3.  1.101
   libswresample   1.  1.100 /  1.  1.100
   libpostproc    53.  3.100 / 53.  3.100
[mpeg2video @ 0x1961bc0] Invalid frame dimensions 0x0.
     Last message repeated 24 times
[mpegts @ 0x195eb80] PES packet size mismatch
Input #0, lavfi, from 'movie=WPEC.ts[out0+subcc]':
   Duration: N/A, start: 16458.590289, bitrate: N/A
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 
1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 90k tbc
     Stream #0:1: Subtitle: eia_608
Output #0, segment, to 'WPEC-%05d.vtt':
   Metadata:
     encoder         : Lavf56.19.100
     Stream #0:0: Subtitle: webvtt
     Metadata:
       encoder         : Lavc56.21.102 webvtt
Stream mapping:
   Stream #0:1 -> #0:0 (eia_608 (cc_dec) -> webvtt (native))
Press [q] to stop, [?] for help
[mpeg2video @ 0x1961bc0] invalid cbp -1 at 113 46
[mpeg2video @ 0x1961bc0] Warning MVs not available
[mpeg2video @ 0x1961bc0] concealing 2640 DC, 2640 AC, 2640 MV errors in 
B frame
size=N/A time=00:06:23.48 bitrate=N/A
video:0kB audio:0kB subtitle:2kB other streams:0kB global headers:0kB 
muxing overhead: unknown