If true, this skips the for loop at the beginning of avpriv_find_start_code().
If the state/start_code input is a local variable and only one buffer is used,
then no history is needed.
In loops and inline functions: if ignoring history, don't initialize start_code,
so it isn't reset twice each time.
cbs_mpeg2.c needs further changes to use output_only = true.
Use output_only = 0 for no functional change. For example, if the
state/start_code
is passed into the function calling avpriv_find_start_code().
---
libavcodec/cavsdec.c | 2 +-
libavcodec/cbs_mpeg2.c | 4 ++--
libavcodec/extract_extradata_bsf.c | 4 ++--
libavcodec/h264_parser.c | 2 +-
libavcodec/internal.h | 9 ++++++++-
libavcodec/mpeg12.c | 2 +-
libavcodec/mpeg12dec.c | 9 ++++-----
libavcodec/mpeg4_unpack_bframes_bsf.c | 3 +--
libavcodec/mpegvideo_parser.c | 5 ++---
libavcodec/remove_extradata_bsf.c | 8 ++++----
libavcodec/utils.c | 14 +++++++++++++-
libavcodec/vc1_common.h | 4 ++--
libavformat/avidec.c | 6 +++---
libavformat/avs2dec.c | 2 +-
libavformat/avs3dec.c | 2 +-
libavformat/cavsvideodec.c | 2 +-
libavformat/mpegtsenc.c | 4 ++--
libavformat/mpegvideodec.c | 2 +-
libavformat/mxfenc.c | 2 +-
libavformat/rtpenc_mpv.c | 4 ++--
20 files changed, 53 insertions(+), 37 deletions(-)
diff --git a/libavcodec/cavsdec.c b/libavcodec/cavsdec.c
index a62177d520..c4c78cd534 100644
--- a/libavcodec/cavsdec.c
+++ b/libavcodec/cavsdec.c
@@ -1248,7 +1248,7 @@ static int cavs_decode_frame(AVCodecContext *avctx, void
*data, int *got_frame,
buf_ptr = buf;
buf_end = buf + buf_size;
for(;;) {
- buf_ptr = avpriv_find_start_code(buf_ptr, buf_end, &stc);
+ buf_ptr = avpriv_find_start_code(buf_ptr, buf_end, &stc, 1);
if (!avpriv_start_code_is_valid(stc) || buf_ptr == buf_end) {
if (!h->stc)
av_log(h->avctx, AV_LOG_WARNING, "no frame decoded\n");
diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c
index eb45929132..d41477620e 100644
--- a/libavcodec/cbs_mpeg2.c
+++ b/libavcodec/cbs_mpeg2.c
@@ -151,7 +151,7 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
int err, i, final = 0;
start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
- &start_code);
+ &start_code, 1);
if (!avpriv_start_code_is_valid(start_code)) {
// No start code found.
return AVERROR_INVALIDDATA;
@@ -169,7 +169,7 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
}
end = avpriv_find_start_code(start--, frag->data + frag->data_size,
- &start_code);
+ &start_code, 0);
// start points to the byte containing the start_code_identifier
// (may be the last byte of fragment->data); end points to the byte
diff --git a/libavcodec/extract_extradata_bsf.c
b/libavcodec/extract_extradata_bsf.c
index 4df1c97139..1a3ddceff2 100644
--- a/libavcodec/extract_extradata_bsf.c
+++ b/libavcodec/extract_extradata_bsf.c
@@ -237,7 +237,7 @@ static int extract_extradata_vc1(AVBSFContext *ctx,
AVPacket *pkt,
int has_extradata = 0, extradata_size = 0;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &state);
+ ptr = avpriv_find_start_code(ptr, end, &state, 1);
if (state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT) {
has_extradata = 1;
} else if (has_extradata && avpriv_start_code_is_valid(state)) {
@@ -300,7 +300,7 @@ static int extract_extradata_mpeg4(AVBSFContext *ctx,
AVPacket *pkt,
uint32_t state = UINT32_MAX;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &state);
+ ptr = avpriv_find_start_code(ptr, end, &state, 1);
if (state == 0x1B3 || state == 0x1B6) {
if (ptr - pkt->data > 4) {
*size = ptr - 4 - pkt->data;
diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c
index 4002bcad77..0ca411c592 100644
--- a/libavcodec/h264_parser.c
+++ b/libavcodec/h264_parser.c
@@ -72,7 +72,7 @@ static int find_start_code(const uint8_t *buf, int buf_size,
{
uint32_t state = -1;
- buf_index = avpriv_find_start_code(buf + buf_index, buf + next_avc + 1,
&state) - buf - 1;
+ buf_index = avpriv_find_start_code(buf + buf_index, buf + next_avc + 1,
&state, 1) - buf - 1;
return FFMIN(buf_index, buf_size);
}
diff --git a/libavcodec/internal.h b/libavcodec/internal.h
index dadd8d4a10..57e2816a95 100644
--- a/libavcodec/internal.h
+++ b/libavcodec/internal.h
@@ -309,6 +309,9 @@ static av_always_inline int
avpriv_start_code_is_valid(uint32_t start_code) {
* By preserving the <b>@p start_code</b> value between subsequent calls, the
caller can
* detect start codes across buffer boundaries.
*
+ * If <b>@p output_only</b> is true, <b>@p start_code</b> is reset to <b>@c ~0
</b>
+ * if @f$ p - end < 4 @f$.
+ *
* @param[in] p A pointer to the start of the memory buffer to scan.
* @param[in] end A pointer to the past-the-end memory address for the buffer
* given by @p p. <b>@p p</b> must be ≤ <b>@p end</b>.
@@ -321,12 +324,16 @@ static av_always_inline int
avpriv_start_code_is_valid(uint32_t start_code) {
* start code (the 4 bytes prior to the returned value,
* using the input history if @f$ p - end < 4 @f$).
*
+ * @param[in] output_only Boolean that if true makes <b>@p start_code</b> an
+ * output only parameter.
+ *
* @return A pointer to the memory address following the found start code, or
<b>@p end</b>
* if no start code was found.
*/
const uint8_t *avpriv_find_start_code(const uint8_t *p,
const uint8_t * const end,
- uint32_t * const start_code);
+ uint32_t * const start_code,
+ int output_only);
int avpriv_codec_get_cap_skip_frame_fill_param(const AVCodec *codec);
diff --git a/libavcodec/mpeg12.c b/libavcodec/mpeg12.c
index e45bc74479..d788aeb9e2 100644
--- a/libavcodec/mpeg12.c
+++ b/libavcodec/mpeg12.c
@@ -203,7 +203,7 @@ int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t
*buf, int buf_size,
}
state++;
} else {
- i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf
- 1;
+ i = avpriv_find_start_code(buf + i, buf + buf_size, &state, 0) -
buf - 1;
if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE &&
state <= SLICE_MAX_START_CODE) {
i++;
pc->frame_start_found = 4;
diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index 6b0b84ae64..cad17d1b1a 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -1771,7 +1771,7 @@ static int mpeg_decode_slice(MpegEncContext *s, int mb_y,
if (avctx->hwaccel && avctx->hwaccel->decode_slice) {
const uint8_t *buf_end, *buf_start = *buf - 4; /* include start_code */
uint32_t start_code = ~0;
- buf_end = avpriv_find_start_code(buf_start + 2, *buf + buf_size,
&start_code);
+ buf_end = avpriv_find_start_code(buf_start + 2, *buf + buf_size,
&start_code, 1);
if (buf_end < *buf + buf_size)
buf_end -= 4;
s->mb_y = mb_y;
@@ -2020,8 +2020,7 @@ static int slice_decode_thread(AVCodecContext *c, void
*arg)
if (s->mb_y == s->end_mb_y)
return 0;
- start_code = -1;
- buf = avpriv_find_start_code(buf, s->gb.buffer_end,
&start_code);
+ buf = avpriv_find_start_code(buf, s->gb.buffer_end,
&start_code, 1);
if (start_code < SLICE_MIN_START_CODE || start_code >
SLICE_MAX_START_CODE)
return AVERROR_INVALIDDATA;
mb_y = start_code - SLICE_MIN_START_CODE;
@@ -2475,8 +2474,8 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame
*picture,
for (;;) {
/* find next start code */
- uint32_t start_code = -1;
- buf_ptr = avpriv_find_start_code(buf_ptr, buf_end, &start_code);
+ uint32_t start_code;
+ buf_ptr = avpriv_find_start_code(buf_ptr, buf_end, &start_code, 1);
if (!avpriv_start_code_is_valid(start_code)) {
if (!skip_frame) {
if (HAVE_THREADS &&
diff --git a/libavcodec/mpeg4_unpack_bframes_bsf.c
b/libavcodec/mpeg4_unpack_bframes_bsf.c
index 6f8595713d..37fb0e4b66 100644
--- a/libavcodec/mpeg4_unpack_bframes_bsf.c
+++ b/libavcodec/mpeg4_unpack_bframes_bsf.c
@@ -36,8 +36,7 @@ static void scan_buffer(const uint8_t *buf, int buf_size,
const uint8_t *end = buf + buf_size, *pos = buf;
while (pos < end) {
- startcode = -1;
- pos = avpriv_find_start_code(pos, end, &startcode);
+ pos = avpriv_find_start_code(pos, end, &startcode, 1);
if (startcode == USER_DATA_STARTCODE && pos_p) {
/* check if the (DivX) userdata string ends with 'p' (packed) */
diff --git a/libavcodec/mpegvideo_parser.c b/libavcodec/mpegvideo_parser.c
index f0897e7e2c..14e350eaea 100644
--- a/libavcodec/mpegvideo_parser.c
+++ b/libavcodec/mpegvideo_parser.c
@@ -68,7 +68,7 @@ static int mpeg1_find_frame_end(ParseContext *pc, const
uint8_t *buf,
}
state++;
} else {
- i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf
- 1;
+ i = avpriv_find_start_code(buf + i, buf + buf_size, &state, 0) -
buf - 1;
if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE &&
state <= SLICE_MAX_START_CODE) {
i++;
pc->frame_start_found = 4;
@@ -120,8 +120,7 @@ static void mpegvideo_extract_headers(AVCodecParserContext
*s,
s->repeat_pict = 0;
while (buf < buf_end) {
- start_code= -1;
- buf= avpriv_find_start_code(buf, buf_end, &start_code);
+ buf = avpriv_find_start_code(buf, buf_end, &start_code, 1);
bytes_left = buf_end - buf;
switch(start_code) {
case PICTURE_START_CODE:
diff --git a/libavcodec/remove_extradata_bsf.c
b/libavcodec/remove_extradata_bsf.c
index 0e42174912..46e914053d 100644
--- a/libavcodec/remove_extradata_bsf.c
+++ b/libavcodec/remove_extradata_bsf.c
@@ -70,7 +70,7 @@ static int h264_split(const uint8_t *buf, int buf_size)
int nalu_type;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &state);
+ ptr = avpriv_find_start_code(ptr, end, &state, 1);
if (!avpriv_start_code_is_valid(state))
break;
nalu_type = state & 0x1F;
@@ -108,7 +108,7 @@ static int hevc_split(const uint8_t *buf, int buf_size)
int nut;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &state);
+ ptr = avpriv_find_start_code(ptr, end, &state, 1);
if (!avpriv_start_code_is_valid(state))
break;
nut = (state >> 1) & 0x3F;
@@ -151,7 +151,7 @@ static int mpeg4video_split(const uint8_t *buf, int
buf_size)
uint32_t state = -1;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &state);
+ ptr = avpriv_find_start_code(ptr, end, &state, 1);
if (state == 0x1B3 || state == 0x1B6)
return ptr - 4 - buf;
}
@@ -166,7 +166,7 @@ static int vc1_split(const uint8_t *buf, int buf_size)
int charged = 0;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &state);
+ ptr = avpriv_find_start_code(ptr, end, &state, 1);
if (state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT) {
charged = 1;
} else if (charged && avpriv_start_code_is_valid(state))
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index cf92d29f67..da057bad3e 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -942,9 +942,20 @@ void ff_thread_report_progress2(AVCodecContext *avctx, int
field, int thread, in
const uint8_t *avpriv_find_start_code(const uint8_t *av_restrict p,
const uint8_t * const end,
- uint32_t * const av_restrict start_code)
+ uint32_t * const av_restrict start_code,
+ const int output_only)
{
av_assert0(p <= end);
+ if (output_only) {
+ // minimum length for a start code
+ if (p + 4 > end) {
+ *start_code = ~0; // set to an invalid start code
+ return end;
+ }
+
+ p += 3; // offset for negative indices in while loop
+ }
+ else {
if (p >= end)
return end;
@@ -958,6 +969,7 @@ const uint8_t *avpriv_find_start_code(const uint8_t
*av_restrict p,
return p;
}
// p is now properly incremented for the negative indices in the while loop
+ }
/* with memory address increasing left to right, we are looking for (in
hexadecimal):
* 00 00 01 XX
diff --git a/libavcodec/vc1_common.h b/libavcodec/vc1_common.h
index 483f86a4ee..453dec34c6 100644
--- a/libavcodec/vc1_common.h
+++ b/libavcodec/vc1_common.h
@@ -57,8 +57,8 @@ enum Profile {
static av_always_inline const uint8_t* find_next_marker(const uint8_t *src,
const uint8_t *end)
{
if (end - src >= 4) {
- uint32_t mrk = 0xFFFFFFFF;
- src = avpriv_find_start_code(src, end, &mrk);
+ uint32_t mrk;
+ src = avpriv_find_start_code(src, end, &mrk, 1);
if (avpriv_start_code_is_valid(mrk))
return src - 4;
}
diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index 86f857b1e3..674f313e84 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -1530,12 +1530,12 @@ resync:
if (index >= 0 && e->timestamp == ast->frame_offset) {
if (index == sti->nb_index_entries-1) {
int key=1;
- uint32_t state=-1;
if (st->codecpar->codec_id == AV_CODEC_ID_MPEG4) {
const uint8_t *ptr = pkt->data, *end = ptr +
FFMIN(size, 256);
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &state);
- if (state == 0x1B6 && ptr < end) {
+ uint32_t start_code;
+ ptr = avpriv_find_start_code(ptr, end,
&start_code, 1);
+ if (start_code == 0x1B6 && ptr < end) {
key = !(*ptr & 0xC0);
break;
}
diff --git a/libavformat/avs2dec.c b/libavformat/avs2dec.c
index bdeb746fc7..f2349dde45 100644
--- a/libavformat/avs2dec.c
+++ b/libavformat/avs2dec.c
@@ -41,7 +41,7 @@ static int avs2_probe(const AVProbeData *p)
}
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &code);
+ ptr = avpriv_find_start_code(ptr, end, &code, 1);
if (avpriv_start_code_is_valid(code)) {
state = code & 0xFF;
if (AVS2_ISUNIT(state)) {
diff --git a/libavformat/avs3dec.c b/libavformat/avs3dec.c
index 2daccd3d15..2238193ff4 100644
--- a/libavformat/avs3dec.c
+++ b/libavformat/avs3dec.c
@@ -35,7 +35,7 @@ static int avs3video_probe(const AVProbeData *p)
int ret = 0;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &code);
+ ptr = avpriv_find_start_code(ptr, end, &code, 1);
if (avpriv_start_code_is_valid(code)) {
state = code & 0xFF;
if (state < AVS3_SEQ_START_CODE) {
diff --git a/libavformat/cavsvideodec.c b/libavformat/cavsvideodec.c
index 1d007708cc..8f4004acea 100644
--- a/libavformat/cavsvideodec.c
+++ b/libavformat/cavsvideodec.c
@@ -37,7 +37,7 @@ static int cavsvideo_probe(const AVProbeData *p)
const uint8_t *ptr = p->buf, *end = p->buf + p->buf_size;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &code);
+ ptr = avpriv_find_start_code(ptr, end, &code, 1);
if (avpriv_start_code_is_valid(code)) {
if(code < CAVS_SEQ_START_CODE) {
/* slices have to be consecutive */
diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index 92b4cc8087..483c65be17 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -1881,7 +1881,7 @@ static int mpegts_write_packet_internal(AVFormatContext
*s, AVPacket *pkt)
extradd = 0;
do {
- p = avpriv_find_start_code(p, buf_end, &state);
+ p = avpriv_find_start_code(p, buf_end, &state, 1);
av_log(s, AV_LOG_TRACE, "nal %"PRId32"\n", state & 0x1f);
if ((state & 0x1f) == 7)
extradd = 0;
@@ -1947,7 +1947,7 @@ static int mpegts_write_packet_internal(AVFormatContext
*s, AVPacket *pkt)
extradd = 0;
do {
- p = avpriv_find_start_code(p, buf_end, &state);
+ p = avpriv_find_start_code(p, buf_end, &state, 1);
av_log(s, AV_LOG_TRACE, "nal %"PRId32"\n", (state & 0x7e)>>1);
if ((state & 0x7e) == 2*32)
extradd = 0;
diff --git a/libavformat/mpegvideodec.c b/libavformat/mpegvideodec.c
index a9829dc1df..840d3565af 100644
--- a/libavformat/mpegvideodec.c
+++ b/libavformat/mpegvideodec.c
@@ -43,7 +43,7 @@ static int mpegvideo_probe(const AVProbeData *p)
int j;
while (ptr < end) {
- ptr = avpriv_find_start_code(ptr, end, &code);
+ ptr = avpriv_find_start_code(ptr, end, &code, 1);
if (avpriv_start_code_is_valid(code)) {
switch(code){
case SEQ_START_CODE:
diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index 5e068c8220..8cec44e89c 100644
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -2242,7 +2242,7 @@ static int mxf_parse_h264_frame(AVFormatContext *s,
AVStream *st,
int i, frame_size, slice_type, has_sps = 0, intra_only = 0, ret;
for (;;) {
- buf = avpriv_find_start_code(buf, buf_end, &state);
+ buf = avpriv_find_start_code(buf, buf_end, &state, 1);
if (buf >= buf_end)
break;
diff --git a/libavformat/rtpenc_mpv.c b/libavformat/rtpenc_mpv.c
index 91c07574bb..3c7168c482 100644
--- a/libavformat/rtpenc_mpv.c
+++ b/libavformat/rtpenc_mpv.c
@@ -54,8 +54,8 @@ void ff_rtp_send_mpegvideo(AVFormatContext *s1, const uint8_t
*buf1, int size)
r1 = buf1;
while (1) {
- uint32_t start_code = ~0;
- r = avpriv_find_start_code(r1, end, &start_code);
+ uint32_t start_code;
+ r = avpriv_find_start_code(r1, end, &start_code, 1);
if (avpriv_start_code_is_valid(start_code)) {
/* New start code found */
if (start_code == 0x100) {
--
2.32.0
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