mirror of https://git.ffmpeg.org/ffmpeg.git
147 lines
4.4 KiB
C
147 lines
4.4 KiB
C
/*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* This bitstream filter splits VP9 superframes into packets containing
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* just one frame.
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*/
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#include <stddef.h>
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#include "avcodec.h"
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#include "bsf.h"
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#include "bitstream.h"
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#include "bytestream.h"
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typedef struct VP9SFSplitContext {
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AVPacket *buffer_pkt;
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int nb_frames;
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int next_frame;
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size_t next_frame_offset;
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int sizes[8];
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} VP9SFSplitContext;
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static int vp9_superframe_split_filter(AVBSFContext *ctx, AVPacket *out)
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{
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VP9SFSplitContext *s = ctx->priv_data;
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AVPacket *in;
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int i, j, ret, marker;
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int is_superframe = !!s->buffer_pkt;
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if (!s->buffer_pkt) {
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ret = ff_bsf_get_packet(ctx, &s->buffer_pkt);
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if (ret < 0)
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return ret;
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in = s->buffer_pkt;
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marker = in->data[in->size - 1];
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if ((marker & 0xe0) == 0xc0) {
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int length_size = 1 + ((marker >> 3) & 0x3);
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int nb_frames = 1 + (marker & 0x7);
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int idx_size = 2 + nb_frames * length_size;
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if (in->size >= idx_size && in->data[in->size - idx_size] == marker) {
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GetByteContext bc;
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int total_size = 0;
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bytestream2_init(&bc, in->data + in->size + 1 - idx_size,
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nb_frames * length_size);
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for (i = 0; i < nb_frames; i++) {
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int frame_size = 0;
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for (j = 0; j < length_size; j++)
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frame_size |= bytestream2_get_byte(&bc) << (j * 8);
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total_size += frame_size;
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if (total_size > in->size - idx_size) {
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av_log(ctx, AV_LOG_ERROR,
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"Invalid frame size in a superframe: %d\n", frame_size);
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ret = AVERROR(EINVAL);
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goto fail;
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}
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s->sizes[i] = frame_size;
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}
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s->nb_frames = nb_frames;
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s->next_frame = 0;
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s->next_frame_offset = 0;
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is_superframe = 1;
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}
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}
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}
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if (is_superframe) {
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BitstreamContext bc;
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int profile, invisible = 0;
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ret = av_packet_ref(out, s->buffer_pkt);
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if (ret < 0)
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goto fail;
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out->data += s->next_frame_offset;
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out->size = s->sizes[s->next_frame];
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s->next_frame_offset += out->size;
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s->next_frame++;
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if (s->next_frame >= s->nb_frames)
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av_packet_free(&s->buffer_pkt);
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ret = bitstream_init8(&bc, out->data, out->size);
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if (ret < 0)
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goto fail;
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bitstream_read(&bc, 2); // frame_marker
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profile = bitstream_read(&bc, 1);
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profile |= bitstream_read(&bc, 1) << 1;
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if (profile == 3)
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bitstream_read(&bc, 1);
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if (!bitstream_read(&bc, 1)) {
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bitstream_read(&bc, 1);
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invisible = !bitstream_read(&bc, 1);
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}
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if (invisible)
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out->pts = AV_NOPTS_VALUE;
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} else {
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av_packet_move_ref(out, s->buffer_pkt);
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av_packet_free(&s->buffer_pkt);
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}
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return 0;
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fail:
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av_packet_free(&s->buffer_pkt);
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return ret;
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}
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static void vp9_superframe_split_uninit(AVBSFContext *ctx)
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{
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VP9SFSplitContext *s = ctx->priv_data;
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av_packet_free(&s->buffer_pkt);
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}
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const AVBitStreamFilter ff_vp9_superframe_split_bsf = {
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.name = "vp9_superframe_split",
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.priv_data_size = sizeof(VP9SFSplitContext),
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.close = vp9_superframe_split_uninit,
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.filter = vp9_superframe_split_filter,
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.codec_ids = (const enum AVCodecID []){ AV_CODEC_ID_VP9, AV_CODEC_ID_NONE },
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};
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