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427 lines
10 KiB
C++
427 lines
10 KiB
C++
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/*
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* mpegconsts.c: Video format constants for MPEG and utilities for display
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* and conversion to format used for yuv4mpeg
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*
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* Copyright (C) 2001 Andrew Stevens <andrew.stevens@philips.com>
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* Copyright (C) 2001 Matthew Marjanovic <maddog@mir.com>
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*
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public License
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <config.h>
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#include "mpegconsts.h"
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#include "yuv4mpeg.h"
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#include "yuv4mpeg_intern.h"
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static y4m_ratio_t mpeg_framerates[] = {
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Y4M_FPS_UNKNOWN,
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Y4M_FPS_NTSC_FILM,
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Y4M_FPS_FILM,
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Y4M_FPS_PAL,
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Y4M_FPS_NTSC,
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Y4M_FPS_30,
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Y4M_FPS_PAL_FIELD,
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Y4M_FPS_NTSC_FIELD,
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Y4M_FPS_60
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};
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#define MPEG_NUM_RATES (sizeof(mpeg_framerates)/sizeof(mpeg_framerates[0]))
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const mpeg_framerate_code_t mpeg_num_framerates = MPEG_NUM_RATES;
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static const char *framerate_definitions[MPEG_NUM_RATES] = {
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"illegal",
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"24000.0/1001.0 (NTSC 3:2 pulldown converted FILM)",
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"24.0 (NATIVE FILM)",
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"25.0 (PAL/SECAM VIDEO / converted FILM)",
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"30000.0/1001.0 (NTSC VIDEO)",
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"30.0",
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"50.0 (PAL FIELD RATE)",
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"60000.0/1001.0 (NTSC FIELD RATE)",
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"60.0"
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};
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static const char *mpeg1_aspect_ratio_definitions[] = {
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"1:1 (square pixels)",
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"1:0.6735",
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"1:0.7031 (16:9 Anamorphic PAL/SECAM for 720x578/352x288 images)",
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"1:0.7615",
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"1:0.8055",
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"1:0.8437 (16:9 Anamorphic NTSC for 720x480/352x240 images)",
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"1:0.8935",
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"1:0.9375 (4:3 PAL/SECAM for 720x578/352x288 images)",
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"1:0.9815",
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"1:1.0255",
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"1:1:0695",
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"1:1.1250 (4:3 NTSC for 720x480/352x240 images)",
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"1:1.1575",
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"1:1.2015"
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};
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static const y4m_ratio_t mpeg1_aspect_ratios[] = {
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Y4M_SAR_MPEG1_1,
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Y4M_SAR_MPEG1_2,
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Y4M_SAR_MPEG1_3, /* Anamorphic 16:9 PAL */
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Y4M_SAR_MPEG1_4,
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Y4M_SAR_MPEG1_5,
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Y4M_SAR_MPEG1_6, /* Anamorphic 16:9 NTSC */
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Y4M_SAR_MPEG1_7,
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Y4M_SAR_MPEG1_8, /* PAL/SECAM 4:3 */
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Y4M_SAR_MPEG1_9,
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Y4M_SAR_MPEG1_10,
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Y4M_SAR_MPEG1_11,
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Y4M_SAR_MPEG1_12, /* NTSC 4:3 */
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Y4M_SAR_MPEG1_13,
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Y4M_SAR_MPEG1_14,
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};
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static const char *mpeg2_aspect_ratio_definitions[] = {
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"1:1 pixels",
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"4:3 display",
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"16:9 display",
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"2.21:1 display"
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};
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static const y4m_ratio_t mpeg2_aspect_ratios[] = {
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Y4M_DAR_MPEG2_1,
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Y4M_DAR_MPEG2_2,
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Y4M_DAR_MPEG2_3,
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Y4M_DAR_MPEG2_4
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};
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static const char **aspect_ratio_definitions[2] = {
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mpeg1_aspect_ratio_definitions,
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mpeg2_aspect_ratio_definitions
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};
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static const y4m_ratio_t *mpeg_aspect_ratios[2] = {
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mpeg1_aspect_ratios,
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mpeg2_aspect_ratios
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};
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const mpeg_aspect_code_t mpeg_num_aspect_ratios[2] = {
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sizeof (mpeg1_aspect_ratios) / sizeof (mpeg1_aspect_ratios[0]),
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sizeof (mpeg2_aspect_ratios) / sizeof (mpeg2_aspect_ratios[0])
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};
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/*
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* Convert MPEG frame-rate code to corresponding frame-rate
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*/
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y4m_ratio_t
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mpeg_framerate (mpeg_framerate_code_t code)
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{
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if (code == 0 || code > mpeg_num_framerates)
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return y4m_fps_UNKNOWN;
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else
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return mpeg_framerates[code];
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}
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/*
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* Look-up MPEG frame rate code for a (exact) frame rate.
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*/
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mpeg_framerate_code_t
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mpeg_framerate_code (y4m_ratio_t framerate)
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{
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mpeg_framerate_code_t i;
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y4m_ratio_reduce (&framerate);
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for (i = 1; i < mpeg_num_framerates; ++i) {
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if (Y4M_RATIO_EQL (framerate, mpeg_framerates[i]))
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return i;
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}
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return 0;
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}
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/* small enough to distinguish 1/1000 from 1/1001 */
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#define MPEG_FPS_TOLERANCE 0.0001
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y4m_ratio_t
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mpeg_conform_framerate (double fps)
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{
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mpeg_framerate_code_t i;
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y4m_ratio_t result;
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/* try to match it to a standard frame rate */
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for (i = 1; i < mpeg_num_framerates; i++) {
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double deviation = 1.0 - (Y4M_RATIO_DBL (mpeg_framerates[i]) / fps);
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if ((deviation > -MPEG_FPS_TOLERANCE) && (deviation < +MPEG_FPS_TOLERANCE))
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return mpeg_framerates[i];
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}
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/* no luck? just turn it into a ratio (6 decimal place accuracy) */
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result.n = (int) ((fps * 1000000.0) + 0.5);
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result.d = 1000000;
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y4m_ratio_reduce (&result);
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return result;
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}
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/*
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* Convert MPEG aspect-ratio code to corresponding aspect-ratio
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*/
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y4m_ratio_t
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mpeg_aspect_ratio (int mpeg_version, mpeg_aspect_code_t code)
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{
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y4m_ratio_t ratio;
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if (mpeg_version < 1 || mpeg_version > 2)
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return y4m_sar_UNKNOWN;
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if (code == 0 || code > mpeg_num_aspect_ratios[mpeg_version - 1])
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return y4m_sar_UNKNOWN;
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else {
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ratio = mpeg_aspect_ratios[mpeg_version - 1][code - 1];
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y4m_ratio_reduce (&ratio);
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return ratio;
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}
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}
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/*
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* Look-up corresponding MPEG aspect ratio code given an exact aspect ratio.
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*
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* WARNING: The semantics of aspect ratio coding *changed* between
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* MPEG1 and MPEG2. In MPEG1 it is the *pixel* aspect ratio. In
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* MPEG2 it is the (far more sensible) aspect ratio of the eventual
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* display.
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*
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*/
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mpeg_aspect_code_t
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mpeg_frame_aspect_code (int mpeg_version, y4m_ratio_t aspect_ratio)
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{
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mpeg_aspect_code_t i;
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y4m_ratio_t red_ratio = aspect_ratio;
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y4m_ratio_reduce (&red_ratio);
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if (mpeg_version < 1 || mpeg_version > 2)
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return 0;
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for (i = 1; i < mpeg_num_aspect_ratios[mpeg_version - 1]; ++i) {
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y4m_ratio_t red_entry = mpeg_aspect_ratios[mpeg_version - 1][i - 1];
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y4m_ratio_reduce (&red_entry);
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if (Y4M_RATIO_EQL (red_entry, red_ratio))
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return i;
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}
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return 0;
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}
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/*
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* Guess the correct MPEG aspect ratio code,
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* given the true sample aspect ratio and frame size of a video stream
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* (and the MPEG version, 1 or 2).
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*
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* Returns 0 if it has no good guess.
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*
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*/
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/* this is big enough to accommodate the difference between 720 and 704 */
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#define GUESS_ASPECT_TOLERANCE 0.03
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mpeg_aspect_code_t
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mpeg_guess_mpeg_aspect_code (int mpeg_version, y4m_ratio_t sampleaspect,
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int frame_width, int frame_height)
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{
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if (Y4M_RATIO_EQL (sampleaspect, y4m_sar_UNKNOWN)) {
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return 0;
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}
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switch (mpeg_version) {
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case 1:
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if (Y4M_RATIO_EQL (sampleaspect, y4m_sar_SQUARE)) {
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return 1;
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} else if (Y4M_RATIO_EQL (sampleaspect, y4m_sar_NTSC_CCIR601)) {
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return 12;
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} else if (Y4M_RATIO_EQL (sampleaspect, y4m_sar_NTSC_16_9)) {
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return 6;
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} else if (Y4M_RATIO_EQL (sampleaspect, y4m_sar_PAL_CCIR601)) {
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return 8;
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} else if (Y4M_RATIO_EQL (sampleaspect, y4m_sar_PAL_16_9)) {
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return 3;
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}
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return 0;
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break;
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case 2:
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if (Y4M_RATIO_EQL (sampleaspect, y4m_sar_SQUARE)) {
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return 1; /* '1' means square *pixels* in MPEG-2; go figure. */
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} else {
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unsigned int i;
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double true_far; /* true frame aspect ratio */
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true_far =
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(double) (sampleaspect.n * frame_width) / (double) (sampleaspect.d * frame_height);
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/* start at '2'... */
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for (i = 2; i < mpeg_num_aspect_ratios[mpeg_version - 1]; i++) {
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double ratio = true_far / Y4M_RATIO_DBL (mpeg_aspect_ratios[mpeg_version - 1][i - 1]);
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if ((ratio > (1.0 - GUESS_ASPECT_TOLERANCE)) && (ratio < (1.0 + GUESS_ASPECT_TOLERANCE)))
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return i;
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}
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return 0;
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}
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break;
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default:
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return 0;
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break;
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}
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}
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/*
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* Guess the true sample aspect ratio of a video stream,
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* given the MPEG aspect ratio code and the actual frame size
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* (and the MPEG version, 1 or 2).
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*
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* Returns y4m_sar_UNKNOWN if it has no good guess.
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*
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*/
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y4m_ratio_t
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mpeg_guess_sample_aspect_ratio (int mpeg_version,
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mpeg_aspect_code_t code, int frame_width, int frame_height)
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{
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switch (mpeg_version) {
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case 1:
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/* MPEG-1 codes turn into SAR's, just not quite the right ones.
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For the common/known values, we provide the ratio used in practice,
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otherwise say we don't know. */
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switch (code) {
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case 1:
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return y4m_sar_SQUARE;
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break;
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case 3:
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return y4m_sar_PAL_16_9;
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break;
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case 6:
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return y4m_sar_NTSC_16_9;
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break;
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case 8:
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return y4m_sar_PAL_CCIR601;
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break;
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case 12:
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return y4m_sar_NTSC_CCIR601;
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break;
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default:
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return y4m_sar_UNKNOWN;
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break;
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}
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break;
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case 2:
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/* MPEG-2 codes turn into Frame Aspect Ratios, though not exactly the
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FAR's used in practice. For common/standard frame sizes, we provide
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the original SAR; otherwise, we say we don't know. */
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if (code == 1) {
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return y4m_sar_SQUARE; /* '1' means square *pixels* in MPEG-2 */
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} else if ((code >= 2) && (code <= 4)) {
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return y4m_guess_sar (frame_width, frame_height, mpeg2_aspect_ratios[code - 1]);
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} else {
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return y4m_sar_UNKNOWN;
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}
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break;
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default:
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return y4m_sar_UNKNOWN;
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break;
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}
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}
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/*
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* Look-up MPEG explanatory definition string for frame rate code
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*
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*/
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const char *
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mpeg_framerate_code_definition (mpeg_framerate_code_t code)
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{
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if (code == 0 || code >= mpeg_num_framerates)
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return "UNDEFINED: illegal/reserved frame-rate ratio code";
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return framerate_definitions[code];
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}
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/*
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* Look-up MPEG explanatory definition string aspect ratio code for an
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* aspect ratio code
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*
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*/
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const char *
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mpeg_aspect_code_definition (int mpeg_version, mpeg_aspect_code_t code)
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{
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if (mpeg_version < 1 || mpeg_version > 2)
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return "UNDEFINED: illegal MPEG version";
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if (code < 1 || code > mpeg_num_aspect_ratios[mpeg_version - 1])
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return "UNDEFINED: illegal aspect ratio code";
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return aspect_ratio_definitions[mpeg_version - 1][code - 1];
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}
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/*
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* Look-up explanatory definition of interlace field order code
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*
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*/
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const char *
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mpeg_interlace_code_definition (int yuv4m_interlace_code)
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{
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const char *def;
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switch (yuv4m_interlace_code) {
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case Y4M_UNKNOWN:
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def = "unknown";
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break;
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case Y4M_ILACE_NONE:
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def = "none/progressive";
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break;
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case Y4M_ILACE_TOP_FIRST:
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def = "top-field-first";
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break;
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case Y4M_ILACE_BOTTOM_FIRST:
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def = "bottom-field-first";
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break;
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default:
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def = "UNDEFINED: illegal video interlacing type-code!";
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break;
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}
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return def;
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}
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/*
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* Local variables:
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* c-file-style: "stroustrup"
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* tab-width: 4
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* indent-tabs-mode: nil
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* End:
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*/
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