LPM audio is being ignored in mpeg ts file(mpegtsdemux)

shiva.mudugal shiva.mudugal at gmail.com
Tue Jul 2 23:57:49 PDT 2013

Hi ,

I am trying to play a mpeg ts file with h264 video and lcpm audio in it. But
"mpegtsdemux" is ignoring the audio and source pad is created only for
video. I added logs in "mpegtsdemux" and printed stream_id and stream_type
for the same. It is stream_id=0xbd and stream_type=0x83.  

I saw in the mpegtsdemux source code that stream_type=0x83 is mapped to
ST_BD_AUDIO_AC3_TRUE_HD and is not handled. But vlc is recognizing it as DVD
lpcm audio.

Can anyone tell me whats the issue.

I used "dvbsnoop" ubuntu utility to analyze the stream. Below is what it
says about audio section.(for one of the ts packets)

Sync-Byte 0x47: 71 (0x47)
Transport_error_indicator: 0 (0x00)  [= packet ok]
Payload_unit_start_indicator: 1 (0x01)  [= Packet data starts]
transport_priority: 0 (0x00)
PID: 68 (0x0044)  [= ]
transport_scrambling_control: 0 (0x00)  [= No scrambling of TS packet
adaptation_field_control: 1 (0x01)  [= no adaptation_field, payload only]
continuity_counter: 0 (0x00)  [= (sequence ok)]
Payload: (len: 184)
     ==> PES-stream: 189 (0xbd)  [= private_stream_1]

Shiva Kumar

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