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avformat/lcevc: add a function to parse sequence and global config blocks

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This exposes parsing already being done to write lvcC boxes, for the purpose
of having these values available elsewhere.
Will be useful for the following change.

Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
James Almer
2026-03-16 18:46:21 -03:00
parent ba793127c4
commit cbfd280f77
2 changed files with 79 additions and 10 deletions
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76
libavformat/lcevc.c
View File

@@ -30,16 +30,6 @@
#include "avio_internal.h"
#include "lcevc.h"
typedef struct LCEVCDecoderConfigurationRecord {
uint8_t profile_idc;
uint8_t level_idc;
uint8_t chroma_format_idc;
uint8_t bit_depth_luma_minus8;
uint8_t bit_depth_chroma_minus8;
uint32_t pic_width_in_luma_samples;
uint32_t pic_height_in_luma_samples;
} LCEVCDecoderConfigurationRecord;
/**
* Rewrite the NALu stripping the unneeded blocks.
* Given that length fields coded inside the NALu are not aware of any emulation_3bytes
@@ -187,6 +177,72 @@ static int write_nalu(LCEVCDecoderConfigurationRecord *lvcc, AVIOContext *pb,
return 0;
}
int ff_lcvec_parse_config_record(LCEVCDecoderConfigurationRecord *lvcc,
const uint8_t *buf, int size)
{
H2645Packet h2645_pkt = { 0 };
AVIOContext *pb;
int ret;
if (size <= 0)
return AVERROR_INVALIDDATA;
if (buf[0] == 1) {
GetBitContext gb;
if (size < 13)
return AVERROR_INVALIDDATA;
ret = init_get_bits8(&gb, buf, 13);
if (ret < 0)
return ret;
memset(lvcc, 0, sizeof(*lvcc));
skip_bits(&gb, 8);
lvcc->profile_idc = get_bits(&gb, 8);
lvcc->level_idc = get_bits(&gb, 8);
lvcc->chroma_format_idc = get_bits(&gb, 2);
lvcc->bit_depth_luma_minus8 = get_bits(&gb, 3);
lvcc->bit_depth_chroma_minus8 = get_bits(&gb, 3);
skip_bits(&gb, 8);
lvcc->pic_width_in_luma_samples = get_bits_long(&gb, 32);
lvcc->pic_height_in_luma_samples = get_bits_long(&gb, 32);
return 0;
}
ret = ffio_open_null_buf(&pb);
if (ret < 0)
return ret;
ret = ff_h2645_packet_split(&h2645_pkt, buf, size, NULL, 0, AV_CODEC_ID_LCEVC, 0);
if (ret < 0)
goto fail;
/* look for IDR or NON_IDR */
for (int i = 0; i < h2645_pkt.nb_nals; i++) {
const H2645NAL *nal = &h2645_pkt.nals[i];
if (nal->type == LCEVC_IDR_NUT) {
ret = write_nalu(lvcc, pb, nal);
if (ret < 0)
goto fail;
} else if (nal->type == LCEVC_NON_IDR_NUT) {
ret = write_nalu(lvcc, pb, nal);
if (ret < 0)
goto fail;
}
}
ret = 0;
fail:
ffio_close_null_buf(pb);
ff_h2645_packet_uninit(&h2645_pkt);
return ret;
}
int ff_isom_write_lvcc(AVIOContext *pb, const uint8_t *data, int len)
{
LCEVCDecoderConfigurationRecord lvcc = { 0 };

13
libavformat/lcevc.h
View File

@@ -24,6 +24,19 @@
#include <stdint.h>
#include "avio.h"
typedef struct LCEVCDecoderConfigurationRecord {
uint8_t profile_idc;
uint8_t level_idc;
uint8_t chroma_format_idc;
uint8_t bit_depth_luma_minus8;
uint8_t bit_depth_chroma_minus8;
uint32_t pic_width_in_luma_samples;
uint32_t pic_height_in_luma_samples;
} LCEVCDecoderConfigurationRecord;
int ff_isom_write_lvcc(AVIOContext *pb, const uint8_t *data, int len);
int ff_lcvec_parse_config_record(LCEVCDecoderConfigurationRecord *lvcc,
const uint8_t *buf, int size);
#endif /* AVFORMAT_LCEVC_H */