ffmpeg/libavcodec/h264_redundant_pps_bsf.c

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/*
* 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 <string.h>
#include "libavutil/common.h"
#include "libavutil/mem.h"
#include "bsf.h"
#include "cbs.h"
#include "cbs_h264.h"
#include "h264.h"
typedef struct H264RedundantPPSContext {
CodedBitstreamContext *input;
CodedBitstreamContext *output;
CodedBitstreamFragment access_unit;
int global_pic_init_qp;
int current_pic_init_qp;
} H264RedundantPPSContext;
static int h264_redundant_pps_fixup_pps(H264RedundantPPSContext *ctx,
H264RawPPS *pps)
{
// Record the current value of pic_init_qp in order to fix up
// following slices, then overwrite with the global value.
ctx->current_pic_init_qp = pps->pic_init_qp_minus26 + 26;
pps->pic_init_qp_minus26 = ctx->global_pic_init_qp - 26;
// Some PPSs have this set, so it must be set in all of them.
// (Slices which do not use such a PPS on input will still have
// *_weight_l*flag as zero and therefore write equivalently.)
pps->weighted_pred_flag = 1;
return 0;
}
static int h264_redundant_pps_fixup_slice(H264RedundantPPSContext *ctx,
H264RawSliceHeader *slice)
{
int qp;
qp = ctx->current_pic_init_qp + slice->slice_qp_delta;
slice->slice_qp_delta = qp - ctx->global_pic_init_qp;
return 0;
}
static int h264_redundant_pps_filter(AVBSFContext *bsf, AVPacket *out)
{
H264RedundantPPSContext *ctx = bsf->priv_data;
AVPacket *in;
CodedBitstreamFragment *au = &ctx->access_unit;
int au_has_sps;
int err, i;
err = ff_bsf_get_packet(bsf, &in);
if (err < 0)
return err;
err = ff_cbs_read_packet(ctx->input, au, in);
if (err < 0)
return err;
au_has_sps = 0;
for (i = 0; i < au->nb_units; i++) {
CodedBitstreamUnit *nal = &au->units[i];
if (nal->type == H264_NAL_SPS)
au_has_sps = 1;
if (nal->type == H264_NAL_PPS) {
h264_redundant_pps_fixup_pps(ctx, nal->content);
if (!au_has_sps) {
av_log(ctx, AV_LOG_VERBOSE, "Deleting redundant PPS "
"at %"PRId64".\n", in->pts);
ff_cbs_delete_unit(ctx->input, au, i);
}
}
if (nal->type == H264_NAL_SLICE ||
nal->type == H264_NAL_IDR_SLICE) {
H264RawSlice *slice = nal->content;
h264_redundant_pps_fixup_slice(ctx, &slice->header);
}
}
err = ff_cbs_write_packet(ctx->output, out, au);
if (err < 0)
return err;
ff_cbs_fragment_uninit(ctx->output, au);
err = av_packet_copy_props(out, in);
if (err < 0)
return err;
av_packet_free(&in);
return 0;
}
static int h264_redundant_pps_init(AVBSFContext *bsf)
{
H264RedundantPPSContext *ctx = bsf->priv_data;
CodedBitstreamFragment *au = &ctx->access_unit;
int err, i;
err = ff_cbs_init(&ctx->input, AV_CODEC_ID_H264, bsf);
if (err < 0)
return err;
err = ff_cbs_init(&ctx->output, AV_CODEC_ID_H264, bsf);
if (err < 0)
return err;
ctx->global_pic_init_qp = 26;
if (bsf->par_in->extradata) {
err = ff_cbs_read_extradata(ctx->input, au, bsf->par_in);
if (err < 0) {
av_log(bsf, AV_LOG_ERROR, "Failed to read extradata.\n");
return err;
}
for (i = 0; i < au->nb_units; i++) {
if (au->units[i].type == H264_NAL_PPS)
h264_redundant_pps_fixup_pps(ctx, au->units[i].content);
}
err = ff_cbs_write_extradata(ctx->output, bsf->par_out, au);
if (err < 0) {
av_log(bsf, AV_LOG_ERROR, "Failed to write extradata.\n");
return err;
}
ff_cbs_fragment_uninit(ctx->output, au);
}
return 0;
}
static void h264_redundant_pps_close(AVBSFContext *bsf)
{
H264RedundantPPSContext *ctx = bsf->priv_data;
ff_cbs_close(&ctx->input);
ff_cbs_close(&ctx->output);
}
static const enum AVCodecID h264_redundant_pps_codec_ids[] = {
AV_CODEC_ID_H264, AV_CODEC_ID_NONE,
};
const AVBitStreamFilter ff_h264_redundant_pps_bsf = {
.name = "h264_redundant_pps",
.priv_data_size = sizeof(H264RedundantPPSContext),
.init = &h264_redundant_pps_init,
.close = &h264_redundant_pps_close,
.filter = &h264_redundant_pps_filter,
.codec_ids = h264_redundant_pps_codec_ids,
};