[FFmpeg-devel] Chinese DTMB streams playback issue

Abylay Ospan aospan at jokersys.com
Fri Jan 5 03:42:33 EET 2018

Hello All,

I have made dump of DTMB streams (digital TV standard in China, like
DVB-T in Europe, etc).

Here is all files shared (50MB from each multiplex frequency):


Here is noted issues:
 * artifacts if we try to play:
  ffplay sands-754mhz.ts

cavs video codec reported:
    Stream #0:13[0x17d]: Video: cavs (B[0][0][0] / 0x0042), yuv420p,
720x576, 25 fps, 25 tbr, 90k tbn, 25 tbc

looks like it's implemented in ./libavcodec/cavsdec.c. Do we have here
video stream not fully compatible with ffmpeg's implementation of cavs
Should I create ticket in https://trac.ffmpeg.org ?

 * no resolution detected and no playback:
  ffmpeg  -i sands-522mhz.ts

looks like because it's scrambled:
PID: 6201 (0x1839)  [= ]
transport_scrambling_control: 2 (0x02)  [= TS packet scrambled with Even Key]
adaptation_field_control: 1 (0x01)  [= no adaptation_field, payload only]
continuity_counter: 11 (0x0b)  [= (sequence ok)]

In this case it's ok, not a problem. May be someone seen CAM modules
to descramble this streams ?  Following CA system id's reported in
               CA_system_ID: 26882 (0x6902)  [= >>ERROR: not (yet)
defined... Report!<<]
               CA_system_ID: 19193 (0x4af9)  [= >>ERROR: not (yet)
defined... Report!<<]
               CA_system_ID: 19238 (0x4b26)  [= >>ERROR: not (yet)
defined... Report!<<]

And one file is playing correctly (sands-722mhz.ts) - it looks
"normal" (h264, mp2).

Abylay Ospan,

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