1 /*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
20
23
25 { 0, 0},
26 {24000, 1001},
27 { 24, 1},
28 { 25, 1},
29 {30000, 1001},
30 { 30, 1},
31 { 50, 1},
32 {60000, 1001},
33 { 60, 1},
34 // Xing's 15fps: (9)
35 { 15, 1},
36 // libmpeg3's "Unofficial economy rates": (10-13)
37 { 5, 1},
38 { 10, 1},
39 { 12, 1},
40 { 15, 1},
41 { 0, 0},
42 };
43
45 int *code, int *ext_n, int *ext_d,
46 int nonstandard)
47 {
48 int mpeg2 = ext_n && ext_d;
49 int max_code = nonstandard ? 12 : 8;
50 int c,
n, d, best_c, best_n, best_d;
52
53 // Default to NTSC if the inputs make no sense.
54 best_c = 4;
55 best_n = best_d = 1;
56
57 for (c = 1; c <= max_code; c++) {
58 if (
av_cmp_q(frame_rate, ff_mpeg12_frame_rate_tab[c]) == 0) {
60 goto found;
61 }
62 }
63
64 for (c = 1; c <= max_code; c++) {
65 for (n = 1; n <= (mpeg2 ? 4 : 1); n++) {
66 for (d = 1; d <= (mpeg2 ? 32 : 1); d++) {
69
70 test =
av_mul_q(ff_mpeg12_frame_rate_tab[c],
72
74 if (cmp == 0) {
77 best_d = d;
78 goto found;
79 }
80
81 if (cmp < 0)
83 else
85
87 if (cmp < 0 || (cmp == 0 && n == 1 && d == 1)) {
90 best_d = d;
92 }
93 }
94 }
95 }
96
97 found:
98 *code = best_c;
99 if (mpeg2) {
100 *ext_n = best_n - 1;
101 *ext_d = best_d - 1;
102 }
103 }
AVRational av_div_q(AVRational b, AVRational c)
Divide one rational by another.
static av_always_inline int cmp(MpegEncContext *s, const int x, const int y, const int subx, const int suby, const int size, const int h, int ref_index, int src_index, me_cmp_func cmp_func, me_cmp_func chroma_cmp_func, const int flags)
compares a block (either a full macroblock or a partition thereof) against a proposed motion-compensa...
static void error(const char *err)
static void test(const char *pattern, const char *host)
Rational number (pair of numerator and denominator).
static int av_cmp_q(AVRational a, AVRational b)
Compare two rationals.
Utilties for rational number calculation.
void ff_mpeg12_find_best_frame_rate(AVRational frame_rate, int *code, int *ext_n, int *ext_d, int nonstandard)
const AVRational ff_mpeg12_frame_rate_tab[16]
AVRational av_mul_q(AVRational b, AVRational c)
Multiply two rationals.