2 * H.264/HEVC common parsing code
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 #include "libavutil/intmath.h"
26 #include "libavutil/intreadwrite.h"
27 #include "libavutil/mem.h"
29 #include "bytestream.h"
31 #include "h2645_parse.h"
33 int ff_h2645_extract_rbsp(const uint8_t *src, int length,
34 H2645NAL *nal, int small_padding)
38 int64_t padding = small_padding ? 0 : MAX_MBPAIR_SIZE;
40 nal->skipped_bytes = 0;
41 #define STARTCODE_TEST \
42 if (i + 2 < length && src[i + 1] == 0 && src[i + 2] <= 3) { \
43 if (src[i + 2] != 3 && src[i + 2] != 0) { \
44 /* startcode, so we must be past the end */ \
49 #if HAVE_FAST_UNALIGNED
50 #define FIND_FIRST_ZERO \
51 if (i > 0 && !src[i]) \
56 for (i = 0; i + 1 < length; i += 9) {
57 if (!((~AV_RN64A(src + i) &
58 (AV_RN64A(src + i) - 0x0100010001000101ULL)) &
59 0x8000800080008080ULL))
66 for (i = 0; i + 1 < length; i += 5) {
67 if (!((~AV_RN32A(src + i) &
68 (AV_RN32A(src + i) - 0x01000101U)) &
75 #endif /* HAVE_FAST_64BIT */
77 for (i = 0; i + 1 < length; i += 2) {
80 if (i > 0 && src[i - 1] == 0)
84 #endif /* HAVE_FAST_UNALIGNED */
86 if (i >= length - 1 && small_padding) { // no escaped 0
90 nal->raw_size = length;
92 } else if (i > length)
95 av_fast_padded_malloc(&nal->rbsp_buffer, &nal->rbsp_buffer_size,
97 if (!nal->rbsp_buffer)
98 return AVERROR(ENOMEM);
100 dst = nal->rbsp_buffer;
104 while (si + 2 < length) {
105 // remove escapes (very rare 1:2^22)
106 if (src[si + 2] > 3) {
107 dst[di++] = src[si++];
108 dst[di++] = src[si++];
109 } else if (src[si] == 0 && src[si + 1] == 0 && src[si + 2] != 0) {
110 if (src[si + 2] == 3) { // escape
115 if (nal->skipped_bytes_pos) {
116 nal->skipped_bytes++;
117 if (nal->skipped_bytes_pos_size < nal->skipped_bytes) {
118 nal->skipped_bytes_pos_size *= 2;
119 av_assert0(nal->skipped_bytes_pos_size >= nal->skipped_bytes);
120 av_reallocp_array(&nal->skipped_bytes_pos,
121 nal->skipped_bytes_pos_size,
122 sizeof(*nal->skipped_bytes_pos));
123 if (!nal->skipped_bytes_pos) {
124 nal->skipped_bytes_pos_size = 0;
125 return AVERROR(ENOMEM);
128 if (nal->skipped_bytes_pos)
129 nal->skipped_bytes_pos[nal->skipped_bytes-1] = di - 1;
132 } else // next start code
136 dst[di++] = src[si++];
139 dst[di++] = src[si++];
142 memset(dst + di, 0, AV_INPUT_BUFFER_PADDING_SIZE);
151 static const char *nal_unit_name(int nal_type)
154 case HEVC_NAL_TRAIL_N : return "TRAIL_N";
155 case HEVC_NAL_TRAIL_R : return "TRAIL_R";
156 case HEVC_NAL_TSA_N : return "TSA_N";
157 case HEVC_NAL_TSA_R : return "TSA_R";
158 case HEVC_NAL_STSA_N : return "STSA_N";
159 case HEVC_NAL_STSA_R : return "STSA_R";
160 case HEVC_NAL_RADL_N : return "RADL_N";
161 case HEVC_NAL_RADL_R : return "RADL_R";
162 case HEVC_NAL_RASL_N : return "RASL_N";
163 case HEVC_NAL_RASL_R : return "RASL_R";
164 case HEVC_NAL_BLA_W_LP : return "BLA_W_LP";
165 case HEVC_NAL_BLA_W_RADL : return "BLA_W_RADL";
166 case HEVC_NAL_BLA_N_LP : return "BLA_N_LP";
167 case HEVC_NAL_IDR_W_RADL : return "IDR_W_RADL";
168 case HEVC_NAL_IDR_N_LP : return "IDR_N_LP";
169 case HEVC_NAL_CRA_NUT : return "CRA_NUT";
170 case HEVC_NAL_VPS : return "VPS";
171 case HEVC_NAL_SPS : return "SPS";
172 case HEVC_NAL_PPS : return "PPS";
173 case HEVC_NAL_AUD : return "AUD";
174 case HEVC_NAL_EOS_NUT : return "EOS_NUT";
175 case HEVC_NAL_EOB_NUT : return "EOB_NUT";
176 case HEVC_NAL_FD_NUT : return "FD_NUT";
177 case HEVC_NAL_SEI_PREFIX : return "SEI_PREFIX";
178 case HEVC_NAL_SEI_SUFFIX : return "SEI_SUFFIX";
179 default : return "?";
183 static int get_bit_length(H2645NAL *nal, int skip_trailing_zeros)
185 int size = nal->size;
188 while (skip_trailing_zeros && size > 0 && nal->data[size - 1] == 0)
194 v = nal->data[size - 1];
196 if (size > INT_MAX / 8)
197 return AVERROR(ERANGE);
200 /* remove the stop bit and following trailing zeros,
201 * or nothing for damaged bitstreams */
203 size -= ff_ctz(v) + 1;
209 * @return AVERROR_INVALIDDATA if the packet is not a valid NAL unit,
210 * 0 if the unit should be skipped, 1 otherwise
212 static int hevc_parse_nal_header(H2645NAL *nal, void *logctx)
214 GetBitContext *gb = &nal->gb;
217 if (get_bits1(gb) != 0)
218 return AVERROR_INVALIDDATA;
220 nal->type = get_bits(gb, 6);
222 nuh_layer_id = get_bits(gb, 6);
223 nal->temporal_id = get_bits(gb, 3) - 1;
224 if (nal->temporal_id < 0)
225 return AVERROR_INVALIDDATA;
227 av_log(logctx, AV_LOG_DEBUG,
228 "nal_unit_type: %d(%s), nuh_layer_id: %d, temporal_id: %d\n",
229 nal->type, nal_unit_name(nal->type), nuh_layer_id, nal->temporal_id);
231 return nuh_layer_id == 0;
234 static int h264_parse_nal_header(H2645NAL *nal, void *logctx)
236 GetBitContext *gb = &nal->gb;
238 if (get_bits1(gb) != 0)
239 return AVERROR_INVALIDDATA;
241 nal->ref_idc = get_bits(gb, 2);
242 nal->type = get_bits(gb, 5);
244 av_log(logctx, AV_LOG_DEBUG,
245 "nal_unit_type: %d, nal_ref_idc: %d\n",
246 nal->type, nal->ref_idc);
251 static int find_next_start_code(const uint8_t *buf, const uint8_t *next_avc)
255 if (buf + 3 >= next_avc)
256 return next_avc - buf;
258 while (buf + i + 3 < next_avc) {
259 if (buf[i] == 0 && buf[i + 1] == 0 && buf[i + 2] == 1)
266 int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
267 void *logctx, int is_nalff, int nal_length_size,
268 enum AVCodecID codec_id, int small_padding)
271 int consumed, ret = 0;
272 int next_avc = is_nalff ? 0 : length;
274 bytestream2_init(&bc, buf, length);
277 while (bytestream2_get_bytes_left(&bc) >= 4) {
279 int extract_length = 0;
280 int skip_trailing_zeros = 1;
282 if (bytestream2_tell(&bc) == next_avc) {
284 extract_length = get_nalsize(nal_length_size,
285 bc.buffer, bytestream2_get_bytes_left(&bc), &i, logctx);
286 if (extract_length < 0)
287 return extract_length;
289 bytestream2_skip(&bc, nal_length_size);
291 next_avc = bytestream2_tell(&bc) + extract_length;
295 if (bytestream2_tell(&bc) > next_avc)
296 av_log(logctx, AV_LOG_WARNING, "Exceeded next NALFF position, re-syncing.\n");
298 /* search start code */
299 buf_index = find_next_start_code(bc.buffer, buf + next_avc);
301 bytestream2_skip(&bc, buf_index);
303 if (!bytestream2_get_bytes_left(&bc)) {
304 if (pkt->nb_nals > 0) {
305 // No more start codes: we discarded some irrelevant
306 // bytes at the end of the packet.
309 av_log(logctx, AV_LOG_ERROR, "No start code is found.\n");
310 return AVERROR_INVALIDDATA;
314 extract_length = FFMIN(bytestream2_get_bytes_left(&bc), next_avc - bytestream2_tell(&bc));
316 if (bytestream2_tell(&bc) >= next_avc) {
317 /* skip to the start of the next NAL */
318 bytestream2_skip(&bc, next_avc - bytestream2_tell(&bc));
323 if (pkt->nals_allocated < pkt->nb_nals + 1) {
324 int new_size = pkt->nals_allocated + 1;
325 void *tmp = av_realloc_array(pkt->nals, new_size, sizeof(*pkt->nals));
328 return AVERROR(ENOMEM);
331 memset(pkt->nals + pkt->nals_allocated, 0,
332 (new_size - pkt->nals_allocated) * sizeof(*pkt->nals));
334 nal = &pkt->nals[pkt->nb_nals];
335 nal->skipped_bytes_pos_size = 1024; // initial buffer size
336 nal->skipped_bytes_pos = av_malloc_array(nal->skipped_bytes_pos_size, sizeof(*nal->skipped_bytes_pos));
337 if (!nal->skipped_bytes_pos)
338 return AVERROR(ENOMEM);
340 pkt->nals_allocated = new_size;
342 nal = &pkt->nals[pkt->nb_nals];
344 consumed = ff_h2645_extract_rbsp(bc.buffer, extract_length, nal, small_padding);
348 if (is_nalff && (extract_length != consumed) && extract_length)
349 av_log(logctx, AV_LOG_DEBUG,
350 "NALFF: Consumed only %d bytes instead of %d\n",
351 consumed, extract_length);
355 bytestream2_skip(&bc, consumed);
357 /* see commit 3566042a0 */
358 if (bytestream2_get_bytes_left(&bc) >= 4 &&
359 bytestream2_peek_be32(&bc) == 0x000001E0)
360 skip_trailing_zeros = 0;
362 nal->size_bits = get_bit_length(nal, skip_trailing_zeros);
364 ret = init_get_bits(&nal->gb, nal->data, nal->size_bits);
368 if (codec_id == AV_CODEC_ID_HEVC)
369 ret = hevc_parse_nal_header(nal, logctx);
371 ret = h264_parse_nal_header(nal, logctx);
372 if (ret <= 0 || nal->size <= 0) {
374 av_log(logctx, AV_LOG_ERROR, "Invalid NAL unit %d, skipping.\n",
384 void ff_h2645_packet_uninit(H2645Packet *pkt)
387 for (i = 0; i < pkt->nals_allocated; i++) {
388 av_freep(&pkt->nals[i].rbsp_buffer);
389 av_freep(&pkt->nals[i].skipped_bytes_pos);
391 av_freep(&pkt->nals);
392 pkt->nals_allocated = 0;