lavc: add a new bitstream filtering API
[libav.git] / libavcodec / hevc_mp4toannexb_bsf.c
1 /*
2 * HEVC MP4 to Annex B byte stream format filter
3 * copyright (c) 2015 Anton Khirnov
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include <string.h>
23
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/mem.h"
26
27 #include "avcodec.h"
28 #include "bsf.h"
29 #include "bytestream.h"
30 #include "hevc.h"
31
32 #define MIN_HEVCC_LENGTH 23
33
34 typedef struct HEVCBSFContext {
35 uint8_t length_size;
36 int extradata_parsed;
37 } HEVCBSFContext;
38
39 static int hevc_extradata_to_annexb(AVBSFContext *ctx)
40 {
41 GetByteContext gb;
42 int length_size, num_arrays, i, j;
43 int ret = 0;
44
45 uint8_t *new_extradata = NULL;
46 size_t new_extradata_size = 0;;
47
48 bytestream2_init(&gb, ctx->par_in->extradata, ctx->par_in->extradata_size);
49
50 bytestream2_skip(&gb, 21);
51 length_size = (bytestream2_get_byte(&gb) & 3) + 1;
52 num_arrays = bytestream2_get_byte(&gb);
53
54 for (i = 0; i < num_arrays; i++) {
55 int type = bytestream2_get_byte(&gb) & 0x3f;
56 int cnt = bytestream2_get_be16(&gb);
57
58 if (!(type == NAL_VPS || type == NAL_SPS || type == NAL_PPS ||
59 type == NAL_SEI_PREFIX || type == NAL_SEI_SUFFIX)) {
60 av_log(ctx, AV_LOG_ERROR, "Invalid NAL unit type in extradata: %d\n",
61 type);
62 ret = AVERROR_INVALIDDATA;
63 goto fail;
64 }
65
66 for (j = 0; j < cnt; j++) {
67 int nalu_len = bytestream2_get_be16(&gb);
68
69 if (4 + AV_INPUT_BUFFER_PADDING_SIZE + nalu_len > SIZE_MAX - new_extradata_size) {
70 ret = AVERROR_INVALIDDATA;
71 goto fail;
72 }
73 ret = av_reallocp(&new_extradata, new_extradata_size + nalu_len + 4 + AV_INPUT_BUFFER_PADDING_SIZE);
74 if (ret < 0)
75 goto fail;
76
77 AV_WB32(new_extradata + new_extradata_size, 1); // add the startcode
78 bytestream2_get_buffer(&gb, new_extradata + new_extradata_size + 4, nalu_len);
79 new_extradata_size += 4 + nalu_len;
80 memset(new_extradata + new_extradata_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
81 }
82 }
83
84 av_freep(&ctx->par_out->extradata);
85 ctx->par_out->extradata = new_extradata;
86 ctx->par_out->extradata_size = new_extradata_size;
87
88 if (!new_extradata_size)
89 av_log(ctx, AV_LOG_WARNING, "No parameter sets in the extradata\n");
90
91 return length_size;
92 fail:
93 av_freep(&new_extradata);
94 return ret;
95 }
96
97 static int hevc_mp4toannexb_init(AVBSFContext *ctx)
98 {
99 HEVCBSFContext *s = ctx->priv_data;
100 int ret;
101
102 if (ctx->par_in->extradata_size < MIN_HEVCC_LENGTH ||
103 AV_RB24(ctx->par_in->extradata) == 1 ||
104 AV_RB32(ctx->par_in->extradata) == 1) {
105 av_log(ctx, AV_LOG_VERBOSE,
106 "The input looks like it is Annex B already\n");
107 } else {
108 ret = hevc_extradata_to_annexb(ctx);
109 if (ret < 0)
110 return ret;
111 s->length_size = ret;
112 s->extradata_parsed = 1;
113 }
114
115 return 0;
116 }
117
118 static int hevc_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
119 {
120 HEVCBSFContext *s = ctx->priv_data;
121 AVPacket *in;
122 GetByteContext gb;
123
124 int got_irap = 0;
125 int i, ret = 0;
126
127 ret = ff_bsf_get_packet(ctx, &in);
128 if (ret < 0)
129 return ret;
130
131 if (!s->extradata_parsed) {
132 av_packet_move_ref(out, in);
133 av_packet_free(&in);
134 return 0;
135 }
136
137 bytestream2_init(&gb, in->data, in->size);
138
139 while (bytestream2_get_bytes_left(&gb)) {
140 uint32_t nalu_size = 0;
141 int nalu_type;
142 int is_irap, add_extradata, extra_size, prev_size;
143
144 for (i = 0; i < s->length_size; i++)
145 nalu_size = (nalu_size << 8) | bytestream2_get_byte(&gb);
146
147 nalu_type = (bytestream2_peek_byte(&gb) >> 1) & 0x3f;
148
149 /* prepend extradata to IRAP frames */
150 is_irap = nalu_type >= 16 && nalu_type <= 23;
151 add_extradata = is_irap && !got_irap;
152 extra_size = add_extradata * ctx->par_out->extradata_size;
153 got_irap |= is_irap;
154
155 if (SIZE_MAX - nalu_size < 4 ||
156 SIZE_MAX - 4 - nalu_size < extra_size) {
157 ret = AVERROR_INVALIDDATA;
158 goto fail;
159 }
160
161 prev_size = out->size;
162
163 ret = av_grow_packet(out, 4 + nalu_size + extra_size);
164 if (ret < 0)
165 goto fail;
166
167 if (add_extradata)
168 memcpy(out->data + prev_size, ctx->par_out->extradata, extra_size);
169 AV_WB32(out->data + prev_size + extra_size, 1);
170 bytestream2_get_buffer(&gb, out->data + prev_size + 4 + extra_size, nalu_size);
171 }
172
173 ret = av_packet_copy_props(out, in);
174 if (ret < 0)
175 goto fail;
176
177 fail:
178 if (ret < 0)
179 av_packet_unref(out);
180 av_packet_free(&in);
181
182 return ret;
183 }
184
185 static const enum AVCodecID codec_ids[] = {
186 AV_CODEC_ID_HEVC, AV_CODEC_ID_NONE,
187 };
188
189 const AVBitStreamFilter ff_hevc_mp4toannexb_bsf = {
190 .name = "hevc_mp4toannexb",
191 .priv_data_size = sizeof(HEVCBSFContext),
192 .init = hevc_mp4toannexb_init,
193 .filter = hevc_mp4toannexb_filter,
194 .codec_ids = codec_ids,
195 };