[Ffmpeg-devel] [BUG] problem ts demuxer h264 bbc

Måns Rullgård mru
Thu Nov 16 22:29:37 CET 2006


Nico Sabbi <nicola_sabbi at fastwebnet.it> writes:

> M?ns Rullg?rd wrote:
>
>>>where do you see the mpeg2 video stream?
>>>
>>>
>>
>>As I said, the PMT indicates an H.264 stream.  Extract this elementary
>>stream and feed it to an MPEG2 video parser:
>>
>> sequence_header                          b3
>> horizontal_size_value                  2d0    720
>> vertical_size_value                    240    576
>> aspect_ratio_information               3      DAR=16/9
>>  frame_rate_code                        3      25 fps
>>  bit_rate_value                         4e20   20000
>>  marker_bit                             1      vbv_buffer_size_value
>> 70     112   constrained_parameters_flag            0
>> load_intra_quantiser_matrix            0
>> load_non_intra_quantiser_matrix        0
>>
>>
>>
>
>>This looks like a perfectly normal MPEG2 video stream, except for that
>>0x61 slice start code, which is not allowed there.  0x61 is however
>>the "start code" for an H.264 NAL unit of a non-IDR slice.  Skipping
>>to byte 0x8e7ab, we encounter this byte sequence (no H.264 parser to
>>hand):
>>
>>0008e7a0  08 30 16 5b 02 00 00 00  01 09 10 00 00 00 01 67
>>0008e7b0  64 40 28 ac 53 b0 16 81  13 61 62 00 00 03 00 02
>>0008e7c0  00 00 03 00 65 28 00 00  00 01 68 fe 3c b0 00 00
>>0008e7d0  00 01 06 01 01 32 06 01  84 80 00 00 00 01 61 be
>>
>>This is a perfectly valid H.264 SPS NAL unit, followed by PPS and SEI.
>>
>>Convinced?
>>
>>
>>
> yes.
> Maybe the first part is the last segment of an mpeg2video stream
> before a transition to H264 (signalled by the pmt) ?

In that case there wouldn't be bits of MPEG2 and H.264 interleaved.

-- 
M?ns Rullg?rd
mru at inprovide.com




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