[linux-dvb] RE : How to convert MPEG-TS to MPEG-PS on the fly?

Thierry Lelegard thierry.lelegard at tv-numeric.com
Fri Aug 22 09:57:07 CEST 2008


On Wed, Aug 20, 2008 at 11:10:06PM +0200, Josef Wolf wrote:

>>   jw at dvb1:~$ dvbsnoop -s pes -if zdf.test|grep Stream_id|head -40
>>   Stream_id: 224 (0xe0)  [= ITU-T Rec. H.262 | ISO/IEC 13818-2 or ISO/IEC 11172-2 video stream]
>>   Stream_id: 0 (0x00)  [= picture_start_code]
>>   Stream_id: 181 (0xb5)  [= extension_start_code]
>>   Stream_id: 1 (0x01)  [= slice_start_code]
>>   Stream_id: 2 (0x02)  [= slice_start_code]
>>   [ consecutive lines deleted ]
>>   Stream_id: 34 (0x22)  [= slice_start_code]
>>   Stream_id: 35 (0x23)  [= slice_start_code]
>>   [ here the list of stream ids start over again and repeats ]
>
> Table 2-18 in iso-13818-1 don't list any stream_id's below 0xBC.
> Anybody knows what those stream_id's 0x00..0x23 and 0xB5 are for
> and whether they could be the reason for the artefacts?

They are defined ISO-13818-2 (MPEG-2 video). They are "start codes"
for PES payload elements. Stream id's (in PES headers, not
payloads) are a subset of start codes and are named "system start
codes". You won't find other start codes in PES headers, only in
PES payloads.

[Quoted from ISO-13818-2]

Table 6-1  Start code values
name                 start code value (hexadecimal)
picture_start_code   00
slice_start_code     01 through AF
reserved             B0
reserved             B1
user_data_start_code B2
sequence_header_code B3
sequence_error_code  B4
extension_start_code B5
reserved             B6
sequence_end_code    B7
group_start_code     B8
system start codes   B9 through FF

NOTE - system start codes are defined in Part 1 of this specification

[End quote]

-Thierry




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