[linux-dvb] Weird TS Stream from DMX_SET_PES_FILTER
bobi at brin.com
Thu Mar 19 23:38:04 CET 2009
I've been using the Linux DVB API to grab DBV-S MPEG2 video packets using a TechniSat S2 card.
But something seems odd about DMX_SET_PES_FILTER.
It returns a TS packets for my pid just fine, but by MPEG2 frames have no PES headers! The raw compressed MPEG2 frames just immediately follow the TS/adapation-field headers directly.
When I wrote my TS packet decoder, I was expecting to have to decode PES headers after the TS header. But instead I found the raw compressed frames.
They decode fine (with ffmpeg's libavcodec mpeg2 decoder,) and they look fine when rendered using SDL.
But besides my own program, I can't get vlc or mplayer to decode this stream. Both vlc and mplayer sense a TS stream, but then they never render anything because, I suspect, that they can't find PES headers.
So, two questions:
1. Am I crazy or is DMX_SET_PES_FILTER returning a non-standard TS stream?
2. Is there a way to receive a compliant MPEG-TS (or MPEG2-PS,) stream?
3. Should I use DMX_SET_FILTER instead?
4. If so, what goes in the filter/mask members of the dmx_filter_t struct?
PS: I use the following to filter on my video stream pid (0x1344):
struct dmx_pes_filter_params f;
memset(&f, 0, sizeof(f));
f.pid = (uint16_t) pid;
f.input = DMX_IN_FRONTEND;
f.output = DMX_OUT_TS_TAP;
f.pes_type = DMX_PES_OTHER;
f.flags = DMX_IMMEDIATE_START;
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