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ffmpeg/libavformat/av1dec.c

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/*
* AV1 Annex B demuxer
* Copyright (c) 2019 James Almer <jamrial@gmail.com>
*
* 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_components.h"
#include "libavutil/common.h"
#include "libavutil/opt.h"
#include "libavcodec/av1_parse.h"
#include "libavcodec/bsf.h"
#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
typedef struct AV1DemuxContext {
const AVClass *class;
AVBSFContext *bsf;
AVRational framerate;
uint32_t temporal_unit_size;
uint32_t frame_unit_size;
} AV1DemuxContext;
//return < 0 if we need more data
static int get_score(int type, int *seq)
{
switch (type) {
case AV1_OBU_SEQUENCE_HEADER:
*seq = 1;
return -1;
case AV1_OBU_FRAME:
case AV1_OBU_FRAME_HEADER:
return *seq ? AVPROBE_SCORE_EXTENSION + 1 : 0;
case AV1_OBU_METADATA:
case AV1_OBU_PADDING:
return -1;
default:
break;
}
return 0;
}
static int av1_read_header(AVFormatContext *s)
{
AV1DemuxContext *const c = s->priv_data;
const AVBitStreamFilter *filter = av_bsf_get_by_name("av1_frame_merge");
AVStream *st;
FFStream *sti;
int ret;
if (!filter) {
av_log(s, AV_LOG_ERROR, "av1_frame_merge bitstream filter "
"not found. This is a bug, please report it.\n");
return AVERROR_BUG;
}
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
sti = ffstream(st);
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_AV1;
sti->need_parsing = AVSTREAM_PARSE_HEADERS;
st->avg_frame_rate = c->framerate;
// taken from rawvideo demuxers
avpriv_set_pts_info(st, 64, 1, 1200000);
ret = av_bsf_alloc(filter, &c->bsf);
if (ret < 0)
return ret;
ret = avcodec_parameters_copy(c->bsf->par_in, st->codecpar);
if (ret < 0)
return ret;
ret = av_bsf_init(c->bsf);
if (ret < 0)
return ret;
return 0;
}
static int av1_read_close(AVFormatContext *s)
{
AV1DemuxContext *const c = s->priv_data;
av_bsf_free(&c->bsf);
return 0;
}
#define DEC AV_OPT_FLAG_DECODING_PARAM
#define OFFSET(x) offsetof(AV1DemuxContext, x)
static const AVOption av1_options[] = {
{ "framerate", "", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, DEC},
{ NULL },
};
#undef OFFSET
static const AVClass av1_demuxer_class = {
.class_name = "AV1 Annex B/low overhead OBU demuxer",
.item_name = av_default_item_name,
.option = av1_options,
.version = LIBAVUTIL_VERSION_INT,
};
#if CONFIG_AV1_DEMUXER
static int leb(AVIOContext *pb, uint32_t *len, int eof) {
int more, i = 0;
*len = 0;
do {
unsigned bits;
int byte = avio_r8(pb);
if (pb->error)
return pb->error;
if (pb->eof_reached)
return (eof && !i) ? AVERROR_EOF : AVERROR_INVALIDDATA;
more = byte & 0x80;
bits = byte & 0x7f;
if (i <= 3 || (i == 4 && bits < (1 << 4)))
*len |= bits << (i * 7);
else if (bits)
return AVERROR_INVALIDDATA;
if (++i == 8 && more)
return AVERROR_INVALIDDATA;
} while (more);
return i;
}
static int read_obu(const uint8_t *buf, int size, int64_t *obu_size, int *type)
{
int start_pos, temporal_id, spatial_id;
int len;
len = parse_obu_header(buf, size, obu_size, &start_pos,
type, &temporal_id, &spatial_id);
if (len < 0)
return len;
return 0;
}
static int annexb_probe(const AVProbeData *p)
{
FFIOContext ctx;
AVIOContext *const pb = &ctx.pub;
int64_t obu_size;
uint32_t temporal_unit_size, frame_unit_size, obu_unit_size;
int seq = 0;
int ret, type, cnt = 0;
ffio_init_read_context(&ctx, p->buf, p->buf_size);
ret = leb(pb, &temporal_unit_size, 1);
if (ret < 0)
return 0;
cnt += ret;
ret = leb(pb, &frame_unit_size, 0);
if (ret < 0 || ((int64_t)frame_unit_size + ret) > temporal_unit_size)
return 0;
cnt += ret;
ret = leb(pb, &obu_unit_size, 0);
if (ret < 0 || ((int64_t)obu_unit_size + ret) >= frame_unit_size)
return 0;
cnt += ret;
frame_unit_size -= obu_unit_size + ret;
avio_skip(pb, obu_unit_size);
if (pb->eof_reached || pb->error)
return 0;
// Check that the first OBU is a Temporal Delimiter.
ret = read_obu(p->buf + cnt, FFMIN(p->buf_size - cnt, obu_unit_size), &obu_size, &type);
if (ret < 0 || type != AV1_OBU_TEMPORAL_DELIMITER || obu_size > 0)
return 0;
cnt += obu_unit_size;
do {
ret = leb(pb, &obu_unit_size, 0);
if (ret < 0 || ((int64_t)obu_unit_size + ret) > frame_unit_size)
return 0;
cnt += ret;
avio_skip(pb, obu_unit_size);
if (pb->eof_reached || pb->error)
return 0;
ret = read_obu(p->buf + cnt, FFMIN(p->buf_size - cnt, obu_unit_size), &obu_size, &type);
if (ret < 0)
return 0;
cnt += obu_unit_size;
ret = get_score(type, &seq);
if (ret >= 0)
return ret;
frame_unit_size -= obu_unit_size + ret;
} while (frame_unit_size);
return 0;
}
static int annexb_read_packet(AVFormatContext *s, AVPacket *pkt)
{
AV1DemuxContext *const c = s->priv_data;
uint32_t obu_unit_size;
int ret, len;
retry:
if (avio_feof(s->pb)) {
if (c->temporal_unit_size || c->frame_unit_size)
return AVERROR_INVALIDDATA;
goto end;
}
if (!c->temporal_unit_size) {
len = leb(s->pb, &c->temporal_unit_size, 1);
if (len == AVERROR_EOF) goto end;
else if (len < 0) return len;
}
if (!c->frame_unit_size) {
len = leb(s->pb, &c->frame_unit_size, 0);
if (len < 0)
return len;
if (((int64_t)c->frame_unit_size + len) > c->temporal_unit_size)
return AVERROR_INVALIDDATA;
c->temporal_unit_size -= len;
}
len = leb(s->pb, &obu_unit_size, 0);
if (len < 0)
return len;
if (((int64_t)obu_unit_size + len) > c->frame_unit_size)
return AVERROR_INVALIDDATA;
ret = av_get_packet(s->pb, pkt, obu_unit_size);
if (ret < 0)
return ret;
if (ret != obu_unit_size)
return AVERROR_INVALIDDATA;
c->temporal_unit_size -= obu_unit_size + len;
c->frame_unit_size -= obu_unit_size + len;
end:
ret = av_bsf_send_packet(c->bsf, pkt);
if (ret < 0) {
av_log(s, AV_LOG_ERROR, "Failed to send packet to "
"av1_frame_merge filter\n");
return ret;
}
ret = av_bsf_receive_packet(c->bsf, pkt);
if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
av_log(s, AV_LOG_ERROR, "av1_frame_merge filter failed to "
"send output packet\n");
if (ret == AVERROR(EAGAIN))
goto retry;
return ret;
}
const AVInputFormat ff_av1_demuxer = {
.name = "av1",
.long_name = NULL_IF_CONFIG_SMALL("AV1 Annex B"),
.priv_data_size = sizeof(AV1DemuxContext),
.flags_internal = FF_FMT_INIT_CLEANUP,
.read_probe = annexb_probe,
.read_header = av1_read_header,
.read_packet = annexb_read_packet,
.read_close = av1_read_close,
.extensions = "obu",
.flags = AVFMT_GENERIC_INDEX | AVFMT_NOTIMESTAMPS,
.priv_class = &av1_demuxer_class,
};
#endif
#if CONFIG_OBU_DEMUXER
//For low overhead obu, we can't foresee the obu size before we parsed the header.
//So, we can't use parse_obu_header here, since it will check size <= buf_size
//see c27c7b49dc for more details
static int read_obu_with_size(const uint8_t *buf, int buf_size, int64_t *obu_size, int *type)
{
GetBitContext gb;
int ret, extension_flag, start_pos;
int64_t size;
ret = init_get_bits8(&gb, buf, FFMIN(buf_size, MAX_OBU_HEADER_SIZE));
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);
if (!get_bits1(&gb)) // has_size_flag
return AVERROR_INVALIDDATA;
skip_bits1(&gb); // obu_reserved_1bit
if (extension_flag) {
get_bits(&gb, 3); // temporal_id
get_bits(&gb, 2); // spatial_id
skip_bits(&gb, 3); // extension_header_reserved_3bits
}
*obu_size = leb128(&gb);
if (*obu_size > INT_MAX)
return AVERROR_INVALIDDATA;
if (get_bits_left(&gb) < 0)
return AVERROR_INVALIDDATA;
start_pos = get_bits_count(&gb) / 8;
size = *obu_size + start_pos;
if (size > INT_MAX)
return AVERROR_INVALIDDATA;
return size;
}
static int obu_probe(const AVProbeData *p)
{
int64_t obu_size;
int seq = 0;
int ret, type, cnt;
// Check that the first OBU is a Temporal Delimiter.
cnt = read_obu_with_size(p->buf, p->buf_size, &obu_size, &type);
if (cnt < 0 || type != AV1_OBU_TEMPORAL_DELIMITER || obu_size != 0)
return 0;
while (1) {
ret = read_obu_with_size(p->buf + cnt, p->buf_size - cnt, &obu_size, &type);
if (ret < 0 || obu_size <= 0)
return 0;
cnt += FFMIN(ret, p->buf_size - cnt);
ret = get_score(type, &seq);
if (ret >= 0)
return ret;
}
return 0;
}
static int obu_get_packet(AVFormatContext *s, AVPacket *pkt)
{
AV1DemuxContext *const c = s->priv_data;
uint8_t header[MAX_OBU_HEADER_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
int64_t obu_size;
int size;
int ret, len, type;
if ((ret = ffio_ensure_seekback(s->pb, MAX_OBU_HEADER_SIZE)) < 0)
return ret;
size = avio_read(s->pb, header, MAX_OBU_HEADER_SIZE);
if (size < 0)
return size;
len = read_obu_with_size(header, size, &obu_size, &type);
if (len < 0) {
av_log(c, AV_LOG_ERROR, "Failed to read obu\n");
return len;
}
avio_seek(s->pb, -size, SEEK_CUR);
ret = av_get_packet(s->pb, pkt, len);
if (ret != len) {
av_log(c, AV_LOG_ERROR, "Failed to get packet for obu\n");
return ret < 0 ? ret : AVERROR_INVALIDDATA;
}
return 0;
}
static int obu_read_packet(AVFormatContext *s, AVPacket *pkt)
{
AV1DemuxContext *const c = s->priv_data;
int ret;
if (s->io_repositioned) {
av_bsf_flush(c->bsf);
s->io_repositioned = 0;
}
while (1) {
ret = obu_get_packet(s, pkt);
/* In case of AVERROR_EOF we need to flush the BSF. Conveniently
* obu_get_packet() returns a blank pkt in this case which
* can be used to signal that the BSF should be flushed. */
if (ret < 0 && ret != AVERROR_EOF)
return ret;
ret = av_bsf_send_packet(c->bsf, pkt);
if (ret < 0) {
av_log(s, AV_LOG_ERROR, "Failed to send packet to "
"av1_frame_merge filter\n");
return ret;
}
ret = av_bsf_receive_packet(c->bsf, pkt);
if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
av_log(s, AV_LOG_ERROR, "av1_frame_merge filter failed to "
"send output packet\n");
if (ret != AVERROR(EAGAIN))
break;
}
return ret;
}
const AVInputFormat ff_obu_demuxer = {
.name = "obu",
.long_name = NULL_IF_CONFIG_SMALL("AV1 low overhead OBU"),
.priv_data_size = sizeof(AV1DemuxContext),
.flags_internal = FF_FMT_INIT_CLEANUP,
.read_probe = obu_probe,
.read_header = av1_read_header,
.read_packet = obu_read_packet,
.read_close = av1_read_close,
.extensions = "obu",
.flags = AVFMT_GENERIC_INDEX | AVFMT_NO_BYTE_SEEK | AVFMT_NOTIMESTAMPS,
.priv_class = &av1_demuxer_class,
};
#endif
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