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
19#include "libavutil/common.h"
20#include "libavutil/opt.h"
21
22#include "bsf.h"
23#include "bsf_internal.h"
24#include "cbs.h"
25#include "cbs_bsf.h"
26#include "cbs_mpeg2.h"
27#include "mpeg12.h"
28
29typedef struct MPEG2MetadataContext {
30    CBSBSFContext common;
31
32    MPEG2RawExtensionData sequence_display_extension;
33
34    AVRational display_aspect_ratio;
35
36    AVRational frame_rate;
37
38    int video_format;
39    int colour_primaries;
40    int transfer_characteristics;
41    int matrix_coefficients;
42
43    int mpeg1_warned;
44} MPEG2MetadataContext;
45
46
47static int mpeg2_metadata_update_fragment(AVBSFContext *bsf,
48                                          AVPacket *pkt,
49                                          CodedBitstreamFragment *frag)
50{
51    MPEG2MetadataContext             *ctx = bsf->priv_data;
52    MPEG2RawSequenceHeader            *sh = NULL;
53    MPEG2RawSequenceExtension         *se = NULL;
54    MPEG2RawSequenceDisplayExtension *sde = NULL;
55    int i, se_pos;
56
57    for (i = 0; i < frag->nb_units; i++) {
58        if (frag->units[i].type == MPEG2_START_SEQUENCE_HEADER) {
59            sh = frag->units[i].content;
60        } else if (frag->units[i].type == MPEG2_START_EXTENSION) {
61            MPEG2RawExtensionData *ext = frag->units[i].content;
62            if (ext->extension_start_code_identifier ==
63                MPEG2_EXTENSION_SEQUENCE) {
64                se = &ext->data.sequence;
65                se_pos = i;
66            } else if (ext->extension_start_code_identifier ==
67                MPEG2_EXTENSION_SEQUENCE_DISPLAY) {
68                sde = &ext->data.sequence_display;
69            }
70        }
71    }
72
73    if (!sh || !se) {
74        // No sequence header and sequence extension: not an MPEG-2 video
75        // sequence.
76        if (sh && !ctx->mpeg1_warned) {
77            av_log(bsf, AV_LOG_WARNING, "Stream contains a sequence "
78                   "header but not a sequence extension: maybe it's "
79                   "actually MPEG-1?\n");
80            ctx->mpeg1_warned = 1;
81        }
82        return 0;
83    }
84
85    if (ctx->display_aspect_ratio.num && ctx->display_aspect_ratio.den) {
86        int num, den;
87
88        av_reduce(&num, &den, ctx->display_aspect_ratio.num,
89                  ctx->display_aspect_ratio.den, 65535);
90
91        if (num == 4 && den == 3)
92            sh->aspect_ratio_information = 2;
93        else if (num == 16 && den == 9)
94            sh->aspect_ratio_information = 3;
95        else if (num == 221 && den == 100)
96            sh->aspect_ratio_information = 4;
97        else
98            sh->aspect_ratio_information = 1;
99    }
100
101    if (ctx->frame_rate.num && ctx->frame_rate.den) {
102        int code, ext_n, ext_d;
103
104        ff_mpeg12_find_best_frame_rate(ctx->frame_rate,
105                                       &code, &ext_n, &ext_d, 0);
106
107        sh->frame_rate_code        = code;
108        se->frame_rate_extension_n = ext_n;
109        se->frame_rate_extension_d = ext_d;
110    }
111
112    if (ctx->video_format             >= 0 ||
113        ctx->colour_primaries         >= 0 ||
114        ctx->transfer_characteristics >= 0 ||
115        ctx->matrix_coefficients      >= 0) {
116        if (!sde) {
117            int err;
118            ctx->sequence_display_extension.extension_start_code =
119                MPEG2_START_EXTENSION;
120            ctx->sequence_display_extension.extension_start_code_identifier =
121                MPEG2_EXTENSION_SEQUENCE_DISPLAY;
122            sde = &ctx->sequence_display_extension.data.sequence_display;
123
124            *sde = (MPEG2RawSequenceDisplayExtension) {
125                .video_format = 5,
126
127                .colour_description       = 0,
128                .colour_primaries         = 2,
129                .transfer_characteristics = 2,
130                .matrix_coefficients      = 2,
131
132                .display_horizontal_size =
133                    se->horizontal_size_extension << 12 | sh->horizontal_size_value,
134                .display_vertical_size =
135                    se->vertical_size_extension << 12 | sh->vertical_size_value,
136            };
137
138            err = ff_cbs_insert_unit_content(frag, se_pos + 1,
139                                             MPEG2_START_EXTENSION,
140                                             &ctx->sequence_display_extension,
141                                             NULL);
142            if (err < 0) {
143                av_log(bsf, AV_LOG_ERROR, "Failed to insert new sequence "
144                       "display extension.\n");
145                return err;
146            }
147        }
148
149        if (ctx->video_format >= 0)
150            sde->video_format = ctx->video_format;
151
152        if (ctx->colour_primaries         >= 0 ||
153            ctx->transfer_characteristics >= 0 ||
154            ctx->matrix_coefficients      >= 0) {
155            sde->colour_description = 1;
156
157            if (ctx->colour_primaries >= 0)
158                sde->colour_primaries = ctx->colour_primaries;
159
160            if (ctx->transfer_characteristics >= 0)
161                sde->transfer_characteristics = ctx->transfer_characteristics;
162
163            if (ctx->matrix_coefficients >= 0)
164                sde->matrix_coefficients = ctx->matrix_coefficients;
165        }
166    }
167
168    return 0;
169}
170
171static const CBSBSFType mpeg2_metadata_type = {
172    .codec_id        = AV_CODEC_ID_MPEG2VIDEO,
173    .fragment_name   = "frame",
174    .unit_name       = "start code",
175    .update_fragment = &mpeg2_metadata_update_fragment,
176};
177
178static int mpeg2_metadata_init(AVBSFContext *bsf)
179{
180    MPEG2MetadataContext *ctx = bsf->priv_data;
181
182#define VALIDITY_CHECK(name) do { \
183        if (!ctx->name) { \
184            av_log(bsf, AV_LOG_ERROR, "The value 0 for %s is " \
185                                      "forbidden.\n", #name); \
186            return AVERROR(EINVAL); \
187        } \
188    } while (0)
189    VALIDITY_CHECK(colour_primaries);
190    VALIDITY_CHECK(transfer_characteristics);
191    VALIDITY_CHECK(matrix_coefficients);
192#undef VALIDITY_CHECK
193
194    return ff_cbs_bsf_generic_init(bsf, &mpeg2_metadata_type);
195}
196
197#define OFFSET(x) offsetof(MPEG2MetadataContext, x)
198#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_BSF_PARAM)
199static const AVOption mpeg2_metadata_options[] = {
200    { "display_aspect_ratio", "Set display aspect ratio (table 6-3)",
201        OFFSET(display_aspect_ratio), AV_OPT_TYPE_RATIONAL,
202        { .dbl = 0.0 }, 0, 65535, FLAGS },
203
204    { "frame_rate", "Set frame rate",
205        OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL,
206        { .dbl = 0.0 }, 0, UINT_MAX, FLAGS },
207
208    { "video_format", "Set video format (table 6-6)",
209        OFFSET(video_format), AV_OPT_TYPE_INT,
210        { .i64 = -1 }, -1, 7, FLAGS },
211    { "colour_primaries", "Set colour primaries (table 6-7)",
212        OFFSET(colour_primaries), AV_OPT_TYPE_INT,
213        { .i64 = -1 }, -1, 255, FLAGS },
214    { "transfer_characteristics", "Set transfer characteristics (table 6-8)",
215        OFFSET(transfer_characteristics), AV_OPT_TYPE_INT,
216        { .i64 = -1 }, -1, 255, FLAGS },
217    { "matrix_coefficients", "Set matrix coefficients (table 6-9)",
218        OFFSET(matrix_coefficients), AV_OPT_TYPE_INT,
219        { .i64 = -1 }, -1, 255, FLAGS },
220
221    { NULL }
222};
223
224static const AVClass mpeg2_metadata_class = {
225    .class_name = "mpeg2_metadata_bsf",
226    .item_name  = av_default_item_name,
227    .option     = mpeg2_metadata_options,
228    .version    = LIBAVUTIL_VERSION_INT,
229};
230
231static const enum AVCodecID mpeg2_metadata_codec_ids[] = {
232    AV_CODEC_ID_MPEG2VIDEO, AV_CODEC_ID_NONE,
233};
234
235const FFBitStreamFilter ff_mpeg2_metadata_bsf = {
236    .p.name         = "mpeg2_metadata",
237    .p.codec_ids    = mpeg2_metadata_codec_ids,
238    .p.priv_class   = &mpeg2_metadata_class,
239    .priv_data_size = sizeof(MPEG2MetadataContext),
240    .init           = &mpeg2_metadata_init,
241    .close          = &ff_cbs_bsf_generic_close,
242    .filter         = &ff_cbs_bsf_generic_filter,
243};
244