[FFmpeg-cvslog] avcodec/h264_mp4toannexb_bsf: refactor start_code_size handling
Zhao Zhili
git at videolan.org
Wed Nov 22 05:47:55 EET 2023
ffmpeg | branch: master | Zhao Zhili <zhilizhao at tencent.com> | Fri May 19 00:46:39 2023 +0800| [91cbae2f6cc77f950459195bdc1bceb7fd4ea9f5] | committer: Zhao Zhili
avcodec/h264_mp4toannexb_bsf: refactor start_code_size handling
start_code_size depends on whether PS comes from out-of-band or
in-band. Make the code more readable.
Signed-off-by: Zhao Zhili <zhilizhao at tencent.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=91cbae2f6cc77f950459195bdc1bceb7fd4ea9f5
---
libavcodec/h264_mp4toannexb_bsf.c | 34 +++++++++++++++++++++++++++-------
1 file changed, 27 insertions(+), 7 deletions(-)
diff --git a/libavcodec/h264_mp4toannexb_bsf.c b/libavcodec/h264_mp4toannexb_bsf.c
index d11be455c2..7dce1ae9b6 100644
--- a/libavcodec/h264_mp4toannexb_bsf.c
+++ b/libavcodec/h264_mp4toannexb_bsf.c
@@ -43,10 +43,26 @@ typedef struct H264BSFContext {
int extradata_parsed;
} H264BSFContext;
+enum PsSource {
+ PS_OUT_OF_BAND = -1,
+ PS_NONE = 0,
+ PS_IN_BAND = 1,
+};
+
static void count_or_copy(uint8_t **out, uint64_t *out_size,
- const uint8_t *in, int in_size, int ps, int copy)
+ const uint8_t *in, int in_size, enum PsSource ps, int copy)
{
- uint8_t start_code_size = ps < 0 ? 0 : *out_size == 0 || ps ? 4 : 3;
+ uint8_t start_code_size;
+
+ if (ps == PS_OUT_OF_BAND)
+ /* start code already present in out-of-band ps data, so don't need to
+ * add it manually again
+ */
+ start_code_size = 0;
+ else if (ps == PS_IN_BAND || *out_size == 0)
+ start_code_size = 4;
+ else
+ start_code_size = 3;
if (copy) {
memcpy(*out + start_code_size, in, in_size);
@@ -202,6 +218,7 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *opkt)
do {
uint32_t nal_size = 0;
+ enum PsSource ps;
/* possible overread ok due to padding */
for (int i = 0; i < s->length_size; i++)
@@ -230,7 +247,7 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *opkt)
if (!s->sps_size) {
LOG_ONCE(ctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n");
} else {
- count_or_copy(&out, &out_size, s->sps, s->sps_size, -1, j);
+ count_or_copy(&out, &out_size, s->sps, s->sps_size, PS_OUT_OF_BAND, j);
sps_seen = 1;
}
}
@@ -246,19 +263,22 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *opkt)
if (new_idr && unit_type == H264_NAL_IDR_SLICE && !sps_seen && !pps_seen) {
if (ctx->par_out->extradata)
count_or_copy(&out, &out_size, ctx->par_out->extradata,
- ctx->par_out->extradata_size, -1, j);
+ ctx->par_out->extradata_size, PS_OUT_OF_BAND, j);
new_idr = 0;
/* if only SPS has been seen, also insert PPS */
} else if (new_idr && unit_type == H264_NAL_IDR_SLICE && sps_seen && !pps_seen) {
if (!s->pps_size) {
LOG_ONCE(ctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
} else {
- count_or_copy(&out, &out_size, s->pps, s->pps_size, -1, j);
+ count_or_copy(&out, &out_size, s->pps, s->pps_size, PS_OUT_OF_BAND, j);
}
}
- count_or_copy(&out, &out_size, buf, nal_size,
- unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS, j);
+ if (unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS)
+ ps = PS_IN_BAND;
+ else
+ ps = PS_NONE;
+ count_or_copy(&out, &out_size, buf, nal_size, ps, j);
if (!new_idr && unit_type == H264_NAL_SLICE) {
new_idr = 1;
sps_seen = 0;
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