The VideoLAN Forums

Hello,

I did a transcoding from MPEG2 video to H.264 video, both in TS format. The VLC shows teletext (the little icon) for the original stream but not for the transcoded stream.

The TSReader shows the teletext for both streams.

Something is making VLC to ignore the teletext descriptors. I turned on VLC message level to 2, the original stream has:

ts debug: * es pid=140 type=6 dr->i_tag=0x56
ts debug: * es pid=140 type=6 dr->i_tag=0x45
ts debug: * ttxt type=Teletext subtitles: hearing impaired lan=fra page=888
ts debug: * ttxt type=Teletext lan=fra page=100
ts debug: * es pid=140 type=6 fcc=telx

The transcoded stream has:

ts debug: * es pid=40 type=6 *unknown*

In terms of above descriptors, I basically copied them byte-by-byte. The overall structure in the PMT are very similar: video, audio, and teletext. The tables in both streams are the same: PAT, PMT, and SDT (for service provider name). It is the same behavior for different versions of pre-built vlc and the source version "1.2.0-git Twoflower (revision 1.1.0-pre1-1651-g28856b8)".

Any help is appreciated. If someone would like to take a look of the streams, I have both of them available (each 1,880,000 bytes).

Thanks in advance.

Liyong

Well, the issue is that the muxer doesn't seem to know about telx

Thanks for the reply. The VLC does recognize the original stream that has basically the same descriptors and structures. Something changed.
liyong