FFmpeg: libavcodec/av1_parse.c Source File

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libavcodec

av1_parse.c

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1 /*

2 * AV1 common parsing code

3 *

4 * This file is part of FFmpeg.

5 *

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.

10 *

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.

15 *

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

19 */

21 #include "config.h"

23 #include "libavutil/mem.h"

25 #include "av1.h"

26 #include "av1_parse.h"

27 #include "bytestream.h"

29 int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length, void *logctx)

30 {

31 int64_t obu_size;

32 int start_pos, type, temporal_id, spatial_id;

33 int len;

35 len = parse_obu_header(buf, length, &obu_size, &start_pos,

36 &type, &temporal_id, &spatial_id);

37 if (len < 0)

38 return len;

40 obu->type = type;

41 obu->temporal_id = temporal_id;

42 obu->spatial_id = spatial_id;

44 obu->data = buf + start_pos;

45 obu->size = obu_size;

46 obu->raw_data = buf;

47 obu->raw_size = len;

49 av_log(logctx, AV_LOG_DEBUG,

50 "obu_type: %d, temporal_id: %d, spatial_id: %d, payload size: %d\n",

51 obu->type, obu->temporal_id, obu->spatial_id, obu->size);

53 return len;

54 }

56 int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length, void *logctx)

57 {

58 GetByteContext bc;

59 int ret, consumed;

61 bytestream2_init(&bc, buf, length);

62 pkt->nb_obus = 0;

64 while (bytestream2_get_bytes_left(&bc) > 0) {

65 AV1OBU *obu;

67 if (pkt->obus_allocated < pkt->nb_obus + 1) {

68 int new_size = pkt->obus_allocated + 1;

69 AV1OBU *tmp;

71 if (new_size >= INT_MAX / sizeof(*tmp))

72 return AVERROR(ENOMEM);

73 tmp = av_fast_realloc(pkt->obus, &pkt->obus_allocated_size, new_size * sizeof(*tmp));

74 if (!tmp)

75 return AVERROR(ENOMEM);

77 pkt->obus = tmp;

78 memset(pkt->obus + pkt->obus_allocated, 0, sizeof(*pkt->obus));

79 pkt->obus_allocated = new_size;

80 }

81 obu = &pkt->obus[pkt->nb_obus];

83 consumed = ff_av1_extract_obu(obu, bc.buffer, bytestream2_get_bytes_left(&bc), logctx);

84 if (consumed < 0)

85 return consumed;

87 bytestream2_skip(&bc, consumed);

89 obu->size_bits = get_obu_bit_length(obu->data, obu->size, obu->type);

91 if (obu->size_bits < 0 || (!obu->size_bits && obu->type != AV1_OBU_TEMPORAL_DELIMITER)) {

92 av_log(logctx, AV_LOG_ERROR, "Invalid OBU of type %d, skipping.\n", obu->type);

93 continue;

94 }

96 pkt->nb_obus++;

98 ret = init_get_bits(&obu->gb, obu->data, obu->size_bits);

99 if (ret < 0)

100 return ret;

101 }

102

103 return 0;

104 }

105

106 void ff_av1_packet_uninit(AV1Packet *pkt)

107 {

108 av_freep(&pkt->obus);

109 pkt->obus_allocated = pkt->obus_allocated_size = 0;

110 }

AVERROR

Filter the word "frame" indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions

AV1OBU::size

int size

Size of payload.

Definition: av1_parse.h:39

GetByteContext

Definition: bytestream.h:33

tmp

static uint8_t tmp[11]

Definition: aes_ctr.c:28

AV1OBU

Definition: av1_parse.h:37

AV1_OBU_TEMPORAL_DELIMITER