From f395431b7d01ed9c311fc53a458eb0434e037936 Mon Sep 17 00:00:00 2001 From: arpi Date: Tue, 30 Oct 2001 18:45:54 +0000 Subject: mpeg video header parser git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@2566 b3059339-0415-0410-9bf9-f77b7e298cf2 --- libmpdemux/mpeg_hdr.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 libmpdemux/mpeg_hdr.c (limited to 'libmpdemux/mpeg_hdr.c') diff --git a/libmpdemux/mpeg_hdr.c b/libmpdemux/mpeg_hdr.c new file mode 100644 index 0000000000..780a5fbfaf --- /dev/null +++ b/libmpdemux/mpeg_hdr.c @@ -0,0 +1,100 @@ + +// based on libmpeg2/header.c by Aaron Holtzman + +// #include +#include + +#include "config.h" +#include "mpeg_hdr.h" + +static int frameratecode2framerate[16] = { + 0, + // Official mpeg1/2 framerates: + 24000*10000/1001, 24*10000,25*10000, 30000*10000/1001, 30*10000,50*10000,60000*10000/1001, 60*10000, + // libmpeg3's "Unofficial economy rates": + 1*10000,5*10000,10*10000,12*10000,15*10000,0,0 +}; + + +int mp_header_process_sequence_header (mp_mpeg_header_t * picture, unsigned char * buffer) +{ + int width, height; + + if ((buffer[6] & 0x20) != 0x20){ + printf("missing marker bit!\n"); + return 1; /* missing marker_bit */ + } + + height = (buffer[0] << 16) | (buffer[1] << 8) | buffer[2]; + + picture->display_picture_width = (height >> 12); + picture->display_picture_height = (height & 0xfff); + + width = ((height >> 12) + 15) & ~15; + height = ((height & 0xfff) + 15) & ~15; + + if ((width > 768) || (height > 576)){ + printf("size restrictions for MP@ML or MPEG1 exceeded! (%dx%d)\n",width,height); +// return 1; /* size restrictions for MP@ML or MPEG1 */ + } + + picture->aspect_ratio_information = buffer[3] >> 4; + picture->frame_rate_code = buffer[3] & 15; + picture->fps=frameratecode2framerate[picture->frame_rate_code]; + picture->bitrate = (buffer[4]<<10)|(buffer[5]<<2)|(buffer[6]>>6); + picture->mpeg1 = 1; + picture->picture_structure = 3; //FRAME_PICTURE; + picture->display_time=100; + return 0; +} + +static int header_process_sequence_extension (mp_mpeg_header_t * picture, + unsigned char * buffer) +{ + /* check chroma format, size extensions, marker bit */ + if (((buffer[1] & 0x07) != 0x02) || (buffer[2] & 0xe0) || + ((buffer[3] & 0x01) != 0x01)) + return 1; + + picture->progressive_sequence = (buffer[1] >> 3) & 1; + picture->mpeg1 = 0; + return 0; +} + +static int header_process_picture_coding_extension (mp_mpeg_header_t * picture, unsigned char * buffer) +{ + picture->picture_structure = buffer[2] & 3; + picture->top_field_first = buffer[3] >> 7; + picture->repeat_first_field = (buffer[3] >> 1) & 1; + picture->progressive_frame = buffer[4] >> 7; + + // repeat_first implementation by A'rpi/ESP-team, based on libmpeg3: + picture->display_time=100; + if(picture->repeat_first_field){ + if(picture->progressive_sequence){ + if(picture->top_field_first) + picture->display_time+=200; + else + picture->display_time+=100; + } else + if(picture->progressive_frame){ + picture->display_time+=50; + } + } + //temopral hack. We calc time on every field, so if we have 2 fields + // interlaced we'll end with double time for 1 frame + if( picture->picture_structure!=3 ) picture->display_time/=2; + return 0; +} + +int mp_header_process_extension (mp_mpeg_header_t * picture, unsigned char * buffer) +{ + switch (buffer[0] & 0xf0) { + case 0x10: /* sequence extension */ + return header_process_sequence_extension (picture, buffer); + case 0x80: /* picture coding extension */ + return header_process_picture_coding_extension (picture, buffer); + } + return 0; +} + -- cgit v1.2.3