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cbs_av1: Make fake OBU size length field a write option

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This is an option to modify the behaviour of the writer, not a syntax
field.
This commit is contained in:
Mark Thompson 2023-09-25 12:44:58 +01:00
parent 1a4bd76ea5
commit 014c138633
3 changed files with 28 additions and 12 deletions
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31
libavcodec/cbs_av1.c
View File

@ -138,19 +138,25 @@ static int cbs_av1_read_leb128(CodedBitstreamContext *ctx, GetBitContext *gbc,
return 0;
}
/** Minimum byte length will be used to indicate the len128 of value if byte_len is 0. */
static int cbs_av1_write_leb128(CodedBitstreamContext *ctx, PutBitContext *pbc,
const char *name, uint64_t value, uint8_t byte_len)
const char *name, uint64_t value, int fixed_length)
{
int len, i;
uint8_t byte;
CBS_TRACE_WRITE_START();
if (byte_len)
av_assert0(byte_len >= (av_log2(value) + 7) / 7);
len = (av_log2(value) + 7) / 7;
len = byte_len ? byte_len : (av_log2(value) + 7) / 7;
if (fixed_length) {
if (fixed_length < len) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "OBU is too large for "
"fixed length size field (%d > %d).\n",
len, fixed_length);
return AVERROR(EINVAL);
}
len = fixed_length;
}
for (i = 0; i < len; i++) {
if (put_bits_left(pbc) < 8)
@ -1006,8 +1012,8 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
if (obu->header.obu_has_size_field) {
pbc_tmp = *pbc;
if (obu->obu_size_byte_len) {
for (int i = 0; i < obu->obu_size_byte_len; i++)
if (priv->fixed_obu_size_length) {
for (int i = 0; i < priv->fixed_obu_size_length; i++)
put_bits(pbc, 8, 0);
} else {
// Add space for the size field to fill later.
@ -1133,7 +1139,8 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
end_pos /= 8;
*pbc = pbc_tmp;
err = cbs_av1_write_leb128(ctx, pbc, "obu_size", obu->obu_size, obu->obu_size_byte_len);
err = cbs_av1_write_leb128(ctx, pbc, "obu_size", obu->obu_size,
priv->fixed_obu_size_length);
if (err < 0)
goto error;
@ -1150,10 +1157,12 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
}
if (obu->obu_size > 0) {
if (!obu->obu_size_byte_len) {
obu->obu_size_byte_len = start_pos - data_pos;
if (!priv->fixed_obu_size_length) {
memmove(pbc->buf + data_pos,
pbc->buf + start_pos, header_size);
} else {
// The size was fixed so the following data was
// already written in the correct place.
}
skip_put_bytes(pbc, header_size);
@ -1273,6 +1282,8 @@ static const CodedBitstreamUnitTypeDescriptor cbs_av1_unit_types[] = {
static const AVOption cbs_av1_options[] = {
{ "operating_point", "Set operating point to select layers to parse from a scalable bitstream",
OFFSET(operating_point), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, AV1_MAX_OPERATING_POINTS - 1, 0 },
{ "fixed_obu_size_length", "Set fixed length of the obu_size field",
OFFSET(fixed_obu_size_length), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 8, 0 },
{ NULL }
};

5
libavcodec/cbs_av1.h
View File

@ -401,7 +401,6 @@ typedef struct AV1RawOBU {
AV1RawOBUHeader header;
size_t obu_size;
uint8_t obu_size_byte_len;
union {
AV1RawSequenceHeader sequence_header;
@ -468,6 +467,10 @@ typedef struct CodedBitstreamAV1Context {
// AVOptions
int operating_point;
// When writing, fix the length in bytes of the obu_size field.
// Writing will fail with an error if an OBU larger than can be
// represented by the fixed size is encountered.
int fixed_obu_size_length;
} CodedBitstreamAV1Context;

4
libavcodec/vaapi_encode_av1.c
View File

@ -634,7 +634,6 @@ static int vaapi_encode_av1_init_picture_params(AVCodecContext *avctx,
}
}
fh_obu->obu_size_byte_len = priv->attr_ext2.bits.obu_size_bytes_minus1 + 1;
ret = vaapi_encode_av1_add_obu(avctx, obu, AV1_OBU_FRAME_HEADER, &priv->fh);
if (ret < 0)
goto end;
@ -839,6 +838,9 @@ static av_cold int vaapi_encode_av1_init(AVCodecContext *avctx)
priv->attr_ext2.value = attr.value;
}
av_opt_set_int(priv->cbc->priv_data, "fixed_obu_size_length",
priv->attr_ext2.bits.obu_size_bytes_minus1 + 1, 0);
ret = vaapi_encode_av1_set_tile(avctx);
if (ret < 0)
return ret;