libdvbpsi: decoding video stream descriptor bug

As it is written in the ISO/IEC 13818-1 standard the video stream descriptor has the following format:

video_stream_descriptor(){

//field number of bits

descriptor_tag 8

descriptor_length 8

multiple_frame_rate_flag 1

frame_rate_code 4

MPEG_1_only_flag 1

constrained_parameter_flag 1

still_picture_flag 1

if (MPEG_1_only_flag = = '0'){

profile_and_level_indication 8

chroma_format                2

frame_rate_extension_flag    1

reserved                     5

}

}

The libdvbpsi function dvbpsi_DecodeVStreamDr decodes that descriptor, but here the field MPEG_1_only_flag is called b_mpeg2.

The problem is that b_mpeg2 must be inverse the MPEG_1_only_flag, but in the source

p_decoded->b_mpeg2 = (p_descriptor->p_data[0] & 0x04) ? 1 : 0; which is in fact MPEG_1_only_flag.

The condition for aditional fields in the standard is if (MPEG_1_only_flag = = '0'){},

but in the source it is if((!p_decoded->b_mpeg2 && (p_descriptor->i_length != 1) || (p_decoded->b_mpeg2 && (p_descriptor->i_length != 3))) which causes an error in decoding a correct descriptor;

So dvbpsi cannot decode a video stream descriptor.

The bug could be corrected by replacing:

p_decoded->b_mpeg2 = (p_descriptor->p_data[0] & 0x04) ? 1 : 0;

with

p_decoded->b_mpeg2 = !((p_descriptor->p_data[0] & 0x04) ? 1 : 0);