/*
* 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
*/
/**
* @file
* This bitstream filter splits AV1 Temporal Units into packets containing
* just one frame, plus any leading and trailing OBUs that may be present at
* the beginning or end, respectively.
*
* Temporal Units already containing only one frame will be passed through
* unchanged. When splitting can't be performed, the Temporal Unit will be
* passed through containing only the remaining OBUs starting from the first
* one after the last successfully split frame.
*/
#include "libavutil/avassert.h"
#include "avcodec.h"
#include "bsf.h"
#include "cbs.h"
#include "cbs_av1.h"
typedef struct AV1FSplitContext {
AVPacket *buffer_pkt;
CodedBitstreamContext *cbc;
CodedBitstreamFragment temporal_unit;
int nb_frames;
int cur_frame;
int cur_frame_idx;
int last_frame_idx;
} AV1FSplitContext;
static int av1_frame_split_filter(AVBSFContext *ctx, AVPacket *out)
{
AV1FSplitContext *s = ctx->priv_data;
CodedBitstreamFragment *td = &s->temporal_unit;
int i, ret;
int split = !!s->buffer_pkt->data;
if (!s->buffer_pkt->data) {
int nb_frames = 0;
ret = ff_bsf_get_packet_ref(ctx, s->buffer_pkt);
if (ret < 0)
return ret;
ret = ff_cbs_read_packet(s->cbc, td, s->buffer_pkt);
if (ret < 0) {
av_log(ctx, AV_LOG_WARNING, "Failed to parse temporal unit.\n");
goto passthrough;
}
for (i = 0; i < td->nb_units; i++) {
CodedBitstreamUnit *unit = &td->units[i];
if (unit->type == AV1_OBU_FRAME ||
unit->type == AV1_OBU_FRAME_HEADER)
nb_frames++;
else if (unit->type == AV1_OBU_TILE_LIST) {
av_log(ctx, AV_LOG_VERBOSE, "Large scale tiles are unsupported.\n");
goto passthrough;
}
}
if (nb_frames > 1) {
s->cur_frame = 0;
s->cur_frame_idx = s->last_frame_idx = 0;
s->nb_frames = nb_frames;
split = 1;
}
}
if (split) {
AV1RawFrameHeader *frame = NULL;
int cur_frame_type = -1, size = 0;
for (i = s->cur_frame_idx; i < td->nb_units; i++) {
CodedBitstreamUnit *unit = &td->units[i];
size += unit->data_size;
if (unit->type == AV1_OBU_FRAME) {
AV1RawOBU *obu = unit->content;
if (frame) {
av_log(ctx, AV_LOG_WARNING, "Frame OBU found when Tile data for a "
"previous frame was expected.\n");
goto passthrough;
}
frame = &obu->obu.frame.header;
cur_frame_type = obu->header.obu_type;
s->last_frame_idx = s->cur_frame_idx;
s->cur_frame_idx = i + 1;
s->cur_frame++;
// split here unless it's the last frame, in which case
// include every trailing OBU
if (s->cur_frame < s->nb_frames)
break;
} else if (unit->type == AV1_OBU_FRAME_HEADER) {
AV1RawOBU *obu = unit->content;
if (frame) {
av_log(ctx, AV_LOG_WARNING, "Frame Header OBU found when Tile data for a "
"previous frame was expected.\n");
goto passthrough;
}
frame = &obu->obu.frame_header;
cur_frame_type = obu->header.obu_type;
s->last_frame_idx = s->cur_frame_idx;
s->cur_frame++;
// split here if show_existing_frame unless it's the last
// frame, in which case include every trailing OBU
if (frame->show_existing_frame &&
s->cur_frame < s->nb_frames) {
s->cur_frame_idx = i + 1;
break;
}
} else if (unit->type == AV1_OBU_TILE_GROUP) {
AV1RawOBU *obu = unit->content;
AV1RawTileGroup *group = &obu->obu.tile_group;
if (!frame || cur_frame_type != AV1_OBU_FRAME_HEADER) {
av_log(ctx, AV_LOG_WARNING, "Unexpected Tile Group OBU found before a "
"Frame Header.\n");
goto passthrough;
}
if ((group->tg_end == (frame->tile_cols * frame->tile_rows) - 1) &&
// include every trailing OBU with the last frame
s->cur_frame < s->nb_frames) {
s->cur_frame_idx = i + 1;
break;
}
}
}
av_assert0(frame && s->cur_frame <= s->nb_frames);
ret = av_packet_ref(out, s->buffer_pkt);
if (ret < 0)
goto fail;
out->data = (uint8_t *)td->units[s->last_frame_idx].data;
out->size = size;
// skip the frame in the buffer packet if it's split successfully, so it's not present
// if the packet is passed through in case of failure when splitting another frame.
s->buffer_pkt->data += size;
s->buffer_pkt->size -= size;
if (!frame->show_existing_frame && !frame->show_frame)
out->pts = AV_NOPTS_VALUE;
if (s->cur_frame == s->nb_frames) {
av_packet_unref(s->buffer_pkt);
ff_cbs_fragment_reset(s->cbc, td);
}
return 0;
}
passthrough:
av_packet_move_ref(out, s->buffer_pkt);
ret = 0;
fail:
if (ret < 0) {
av_packet_unref(out);
av_packet_unref(s->buffer_pkt);
}
ff_cbs_fragment_reset(s->cbc, td);
return ret;
}
static const CodedBitstreamUnitType decompose_unit_types[] = {
AV1_OBU_TEMPORAL_DELIMITER,
AV1_OBU_SEQUENCE_HEADER,
AV1_OBU_FRAME_HEADER,
AV1_OBU_TILE_GROUP,
AV1_OBU_FRAME,
};
static int av1_frame_split_init(AVBSFContext *ctx)
{
AV1FSplitContext *s = ctx->priv_data;
CodedBitstreamFragment *td = &s->temporal_unit;
int ret;
s->buffer_pkt = av_packet_alloc();
if (!s->buffer_pkt)
return AVERROR(ENOMEM);
ret = ff_cbs_init(&s->cbc, AV_CODEC_ID_AV1, ctx);
if (ret < 0)
return ret;
s->cbc->decompose_unit_types = (CodedBitstreamUnitType*)decompose_unit_types;
s->cbc->nb_decompose_unit_types = FF_ARRAY_ELEMS(decompose_unit_types);
if (!ctx->par_in->extradata_size)
return 0;
ret = ff_cbs_read_extradata(s->cbc, td, ctx->par_in);
if (ret < 0)
av_log(ctx, AV_LOG_WARNING, "Failed to parse extradata.\n");
ff_cbs_fragment_reset(s->cbc, td);
return 0;
}
static void av1_frame_split_flush(AVBSFContext *ctx)
{
AV1FSplitContext *s = ctx->priv_data;
av_packet_unref(s->buffer_pkt);
ff_cbs_fragment_reset(s->cbc, &s->temporal_unit);
}
static void av1_frame_split_close(AVBSFContext *ctx)
{
AV1FSplitContext *s = ctx->priv_data;
av_packet_free(&s->buffer_pkt);
ff_cbs_fragment_free(s->cbc, &s->temporal_unit);
ff_cbs_close(&s->cbc);
}
static const enum AVCodecID av1_frame_split_codec_ids[] = {
AV_CODEC_ID_AV1, AV_CODEC_ID_NONE,
};
const AVBitStreamFilter ff_av1_frame_split_bsf = {
.name = "av1_frame_split",
.priv_data_size = sizeof(AV1FSplitContext),
.init = av1_frame_split_init,
.flush = av1_frame_split_flush,
.close = av1_frame_split_close,
.filter = av1_frame_split_filter,
.codec_ids = av1_frame_split_codec_ids,
};