diff options
Diffstat (limited to 'sys/vdpau/mpegutil.c')
| -rw-r--r-- | sys/vdpau/mpegutil.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/sys/vdpau/mpegutil.c b/sys/vdpau/mpegutil.c new file mode 100644 index 00000000..274fa853 --- /dev/null +++ b/sys/vdpau/mpegutil.c @@ -0,0 +1,227 @@ +/* GStreamer + * Copyright (C) 2007 Jan Schmidt <thaytan@mad.scientist.com> + * Copyright (C) 2009 Carl-Anton Ingmarsson <ca.ingmarsson@gmail.com> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +#include "mpegutil.h" + +guint8 bits[] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 }; + +guint32 +read_bits (guint8 * buf, gint start_bit, gint n_bits) +{ + gint i; + guint32 ret = 0x00; + + buf += start_bit / 8; + start_bit %= 8; + + for (i = 0; i < n_bits; i++) { + guint32 tmp; + + tmp = ((*buf & bits[start_bit]) >> (7 - start_bit)); + ret = (ret | (tmp << (n_bits - i - 1))); + if (++start_bit == 8) { + buf += 1; + start_bit = 0; + } + } + + return ret; +} + +guint8 * +mpeg_util_find_start_code (guint32 * sync_word, guint8 * cur, guint8 * end) +{ + guint32 code; + + if (G_UNLIKELY (cur == NULL)) + return NULL; + + code = *sync_word; + + while (cur < end) { + code <<= 8; + + if (code == 0x00000100) { + /* Reset the sync word accumulator */ + *sync_word = 0xffffffff; + return cur; + } + + /* Add the next available byte to the collected sync word */ + code |= *cur++; + } + + *sync_word = code; + return NULL; +} + +static void +set_fps_from_code (MPEGSeqHdr * hdr, guint8 fps_code) +{ + const gint framerates[][2] = { + {30, 1}, {24000, 1001}, {24, 1}, {25, 1}, + {30000, 1001}, {30, 1}, {50, 1}, {60000, 1001}, + {60, 1}, {30, 1} + }; + + if (fps_code < 10) { + hdr->fps_n = framerates[fps_code][0]; + hdr->fps_d = framerates[fps_code][1]; + } else { + /* Force a valid framerate */ + hdr->fps_n = 30000; + hdr->fps_d = 1001; + } +} + +/* Set the Pixel Aspect Ratio in our hdr from a DAR code in the data */ +static void +set_par_from_dar (MPEGSeqHdr * hdr, guint8 asr_code) +{ + /* Pixel_width = DAR_width * display_vertical_size */ + /* Pixel_height = DAR_height * display_horizontal_size */ + switch (asr_code) { + case 0x02: /* 3:4 DAR = 4:3 pixels */ + hdr->par_w = 4 * hdr->height; + hdr->par_h = 3 * hdr->width; + break; + case 0x03: /* 9:16 DAR */ + hdr->par_w = 16 * hdr->height; + hdr->par_h = 9 * hdr->width; + break; + case 0x04: /* 1:2.21 DAR */ + hdr->par_w = 221 * hdr->height; + hdr->par_h = 100 * hdr->width; + break; + case 0x01: /* Square pixels */ + default: + hdr->par_w = hdr->par_h = 1; + break; + } +} + +static gboolean +mpeg_util_parse_extension_packet (MPEGSeqHdr * hdr, guint8 * data, guint8 * end) +{ + guint8 ext_code; + + if (G_UNLIKELY (data >= end)) + return FALSE; /* short extension packet */ + + ext_code = data[0] >> 4; + + switch (ext_code) { + case MPEG_PACKET_EXT_SEQUENCE: + { + /* Parse a Sequence Extension */ + guint8 horiz_size_ext, vert_size_ext; + guint8 fps_n_ext, fps_d_ext; + + if (G_UNLIKELY ((end - data) < 6)) + /* need at least 10 bytes, minus 4 for the start code 000001b5 */ + return FALSE; + + horiz_size_ext = ((data[1] << 1) & 0x02) | ((data[2] >> 7) & 0x01); + vert_size_ext = (data[2] >> 5) & 0x03; + hdr->profile = read_bits (data, 7, 3); + fps_n_ext = (data[5] >> 5) & 0x03; + fps_d_ext = data[5] & 0x1f; + + hdr->fps_n *= (fps_n_ext + 1); + hdr->fps_d *= (fps_d_ext + 1); + hdr->width += (horiz_size_ext << 12); + hdr->height += (vert_size_ext << 12); + break; + } + default: + break; + } + + return TRUE; +} + +gboolean +mpeg_util_parse_sequence_hdr (MPEGSeqHdr * hdr, guint8 * data, guint8 * end) +{ + guint32 code; + guint8 dar_idx, fps_idx; + guint32 sync_word = 0xffffffff; + gboolean constrained_flag; + gboolean load_intra_flag; + gboolean load_non_intra_flag; + + if (G_UNLIKELY ((end - data) < 12)) + return FALSE; /* Too small to be a sequence header */ + + code = GST_READ_UINT32_BE (data); + if (G_UNLIKELY (code != (0x00000100 | MPEG_PACKET_SEQUENCE))) + return FALSE; + + /* Skip the sync word */ + data += 4; + + /* Parse the MPEG 1 bits */ + hdr->mpeg_version = 1; + + code = GST_READ_UINT32_BE (data); + hdr->width = (code >> 20) & 0xfff; + hdr->height = (code >> 8) & 0xfff; + + dar_idx = (code >> 4) & 0xf; + set_par_from_dar (hdr, dar_idx); + fps_idx = code & 0xf; + set_fps_from_code (hdr, fps_idx); + + constrained_flag = (data[7] >> 2) & 0x01; + load_intra_flag = (data[7] >> 1) & 0x01; + if (load_intra_flag) { + if (G_UNLIKELY ((end - data) < 64)) + return FALSE; + data += 64; + } + + load_non_intra_flag = data[7] & 0x01; + if (load_non_intra_flag) { + if (G_UNLIKELY ((end - data) < 64)) + return FALSE; + data += 64; + } + + /* Advance past the rest of the MPEG-1 header */ + data += 8; + + /* Read MPEG-2 sequence extensions */ + data = mpeg_util_find_start_code (&sync_word, data, end); + while (data != NULL) { + if (G_UNLIKELY (data >= end)) + return FALSE; + + /* data points at the last byte of the start code */ + if (data[0] == MPEG_PACKET_EXTENSION) { + if (!mpeg_util_parse_extension_packet (hdr, data + 1, end)) + return FALSE; + + hdr->mpeg_version = 2; + } + data = mpeg_util_find_start_code (&sync_word, data, end); + } + + return TRUE; +} |