[FFmpeg-cvslog] avcodec: add AV1 packet split API
James Almer
git at videolan.org
Fri Jul 20 18:58:14 EEST 2018
ffmpeg | branch: master | James Almer <jamrial at gmail.com> | Sat Apr 14 17:29:31 2018 -0300| [45f52d19b98fed72682ee5ad3a0f93c71c7c4944] | committer: James Almer
avcodec: add AV1 packet split API
Signed-off-by: James Almer <jamrial at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=45f52d19b98fed72682ee5ad3a0f93c71c7c4944
---
libavcodec/av1_parse.c | 103 ++++++++++++++++++++++++++++++++++++++++
libavcodec/av1_parse.h | 126 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 229 insertions(+)
diff --git a/libavcodec/av1_parse.c b/libavcodec/av1_parse.c
new file mode 100644
index 0000000000..48feb9fb8a
--- /dev/null
+++ b/libavcodec/av1_parse.c
@@ -0,0 +1,103 @@
+/*
+ * AV1 common parsing code
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config.h"
+
+#include "libavutil/mem.h"
+
+#include "av1_parse.h"
+#include "bytestream.h"
+
+int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length, void *logctx)
+{
+ int64_t obu_size;
+ int start_pos, type, temporal_id, spatial_id;
+
+ int ret = parse_obu_header(buf, length, &obu_size, &start_pos,
+ &type, &temporal_id, &spatial_id);
+ if (ret < 0)
+ return ret;
+
+ if (obu_size > INT_MAX / 8 || obu_size < 0)
+ return AVERROR(ERANGE);
+
+ obu->type = type;
+ obu->temporal_id = temporal_id;
+ obu->spatial_id = spatial_id;
+
+ length = obu_size + start_pos;
+
+ obu->data = buf + start_pos;
+ obu->size = obu_size;
+ obu->raw_data = buf;
+ obu->raw_size = length;
+
+ ret = init_get_bits(&obu->gb, obu->data, obu->size * 8);
+ if (ret < 0)
+ return ret;
+
+ av_log(logctx, AV_LOG_DEBUG,
+ "obu_type: %d, temporal_id: %d, spatial_id: %d, payload size: %d\n",
+ obu->type, obu->temporal_id, obu->spatial_id, obu->size);
+
+ return length;
+}
+
+int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length, void *logctx)
+{
+ GetByteContext bc;
+ int consumed;
+
+ bytestream2_init(&bc, buf, length);
+ pkt->nb_obus = 0;
+
+ while (bytestream2_get_bytes_left(&bc) > 0) {
+ AV1OBU *obu;
+
+ if (pkt->obus_allocated < pkt->nb_obus + 1) {
+ int new_size = pkt->obus_allocated + 1;
+ AV1OBU *tmp = av_realloc_array(pkt->obus, new_size, sizeof(*tmp));
+ if (!tmp)
+ return AVERROR(ENOMEM);
+
+ pkt->obus = tmp;
+ memset(pkt->obus + pkt->obus_allocated, 0,
+ (new_size - pkt->obus_allocated) * sizeof(*tmp));
+ pkt->obus_allocated = new_size;
+ }
+ obu = &pkt->obus[pkt->nb_obus];
+
+ consumed = ff_av1_extract_obu(obu, bc.buffer, bytestream2_get_bytes_left(&bc), logctx);
+ if (consumed < 0)
+ return consumed;
+
+ pkt->nb_obus++;
+
+ bytestream2_skip(&bc, consumed);
+ }
+
+ return 0;
+}
+
+void ff_av1_packet_uninit(AV1Packet *pkt)
+{
+ av_freep(&pkt->obus);
+ pkt->obus_allocated = 0;
+}
diff --git a/libavcodec/av1_parse.h b/libavcodec/av1_parse.h
new file mode 100644
index 0000000000..84fc71c925
--- /dev/null
+++ b/libavcodec/av1_parse.h
@@ -0,0 +1,126 @@
+/*
+ * AV1 common parsing code
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_AV1_PARSE_H
+#define AVCODEC_AV1_PARSE_H
+
+#include <stdint.h>
+
+#include "avcodec.h"
+#include "get_bits.h"
+
+typedef struct AV1OBU {
+ /** Size of payload */
+ int size;
+ const uint8_t *data;
+
+ /** Size of entire OBU, including header */
+ int raw_size;
+ const uint8_t *raw_data;
+
+ /** GetBitContext initialized to the start of the payload */
+ GetBitContext gb;
+
+ int type;
+
+ int temporal_id;
+ int spatial_id;
+} AV1OBU;
+
+/** An input packet split into OBUs */
+typedef struct AV1Packet {
+ AV1OBU *obus;
+ int nb_obus;
+ int obus_allocated;
+} AV1Packet;
+
+/**
+ * Extract an OBU from a raw bitstream.
+ *
+ * @note This function does not copy or store any bistream data. All
+ * the pointers in the AV1OBU structure will be valid as long
+ * as the input buffer also is.
+ */
+int ff_av1_extract_obu(AV1OBU *obu, const uint8_t *buf, int length,
+ void *logctx);
+
+/**
+ * Split an input packet into OBUs.
+ *
+ * @note This function does not copy or store any bistream data. All
+ * the pointers in the AV1Packet structure will be valid as
+ * long as the input buffer also is.
+ */
+int ff_av1_packet_split(AV1Packet *pkt, const uint8_t *buf, int length,
+ void *logctx);
+
+/**
+ * Free all the allocated memory in the packet.
+ */
+void ff_av1_packet_uninit(AV1Packet *pkt);
+
+static inline int64_t leb128(GetBitContext *gb) {
+ int64_t ret = 0;
+ int i;
+
+ for (i = 0; i < 8; i++) {
+ int byte = get_bits(gb, 8);
+ ret |= (int64_t)(byte & 0x7f) << (i * 7);
+ if (!(byte & 0x80))
+ break;
+ }
+ return ret;
+}
+
+static inline int parse_obu_header(const uint8_t *buf, int buf_size,
+ int64_t *obu_size, int *start_pos, int *type,
+ int *temporal_id, int *spatial_id)
+{
+ GetBitContext gb;
+ int ret, extension_flag, has_size_flag;
+
+ ret = init_get_bits8(&gb, buf, FFMIN(buf_size, 2 + 8)); // OBU header fields + max leb128 length
+ if (ret < 0)
+ return ret;
+
+ if (get_bits1(&gb) != 0) // obu_forbidden_bit
+ return AVERROR_INVALIDDATA;
+
+ *type = get_bits(&gb, 4);
+ extension_flag = get_bits1(&gb);
+ has_size_flag = get_bits1(&gb);
+ skip_bits1(&gb); // obu_reserved_1bit
+
+ if (extension_flag) {
+ *temporal_id = get_bits(&gb, 3);
+ *spatial_id = get_bits(&gb, 2);
+ skip_bits(&gb, 3); // extension_header_reserved_3bits
+ } else {
+ *temporal_id = *spatial_id = 0;
+ }
+
+ *obu_size = has_size_flag ? leb128(&gb)
+ : buf_size - 1 - extension_flag;
+ *start_pos = get_bits_count(&gb) / 8;
+
+ return 0;
+}
+
+#endif /* AVCODEC_AV1_PARSE_H */
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