PR #24327 opened by michaelni
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24327
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24327.patch
┌─────────────────────────────────────────┬───────────┬───────────┬──────────────────────┐
│ sample │ master │ skipframe │
│
├─────────────────────────────────────────┼───────────┼───────────┼──────────────────────┤
│ loewe.ts (hevc/TS) │ 17.2 ±1.0 │ 4.8 ±0.5 │ 3.56×
(p=2e-71) │
├─────────────────────────────────────────┼───────────┼───────────┼──────────────────────┤
│ DELTAQP_A_BRCM_4.bit │ 21.7 ±0.7 │ 10.6 ±0.3 │ 2.05×
(p=3e-78) │
├─────────────────────────────────────────┼───────────┼───────────┼──────────────────────┤
│ hevc/paramchange │ 59.8 ±1.7 │ 4.3 ±0.3 │ 13.93×
(p=2e-79) │
└─────────────────────────────────────────┴───────────┴───────────┴──────────────────────┘
# Summary of changes
Briefly describe what this PR does and why.
<!--
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From 0672f52121db8bf32191c9184e2c9a9719be88cc Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <[email protected]>
Date: Mon, 31 Aug 2026 03:32:50 +0200
Subject: [PATCH] avcodec/hevc: fill the stream parameters when all frames are
skipped
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
┌─────────────────────────────────────────┬───────────┬───────────┬──────────────────────┐
│ sample │ master │ skipframe │
│
├─────────────────────────────────────────┼───────────┼───────────┼──────────────────────┤
│ loewe.ts (hevc/TS) │ 17.2 ±1.0 │ 4.8 ±0.5 │ 3.56×
(p=2e-71) │
├─────────────────────────────────────────┼───────────┼───────────┼──────────────────────┤
│ DELTAQP_A_BRCM_4.bit │ 21.7 ±0.7 │ 10.6 ±0.3 │ 2.05×
(p=3e-78) │
├─────────────────────────────────────────┼───────────┼───────────┼──────────────────────┤
│ hevc/paramchange │ 59.8 ±1.7 │ 4.3 ±0.3 │ 13.93×
(p=2e-79) │
└─────────────────────────────────────────┴───────────┴───────────┴──────────────────────┘
---
libavcodec/hevc/hevcdec.c | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
diff --git a/libavcodec/hevc/hevcdec.c b/libavcodec/hevc/hevcdec.c
index 475c2738b1..bc8fca0ed6 100644
--- a/libavcodec/hevc/hevcdec.c
+++ b/libavcodec/hevc/hevcdec.c
@@ -3793,8 +3793,18 @@ static int decode_nal_units(HEVCContext *s, const
uint8_t *buf, int length)
H2645NAL *nal = &s->pkt.nals[i];
if (s->avctx->skip_frame >= AVDISCARD_ALL ||
- (s->avctx->skip_frame >= AVDISCARD_NONREF &&
ff_hevc_nal_is_nonref(nal->type)))
- continue;
+ (s->avctx->skip_frame >= AVDISCARD_NONREF &&
ff_hevc_nal_is_nonref(nal->type))) {
+ switch (nal->type) {
+ case HEVC_NAL_VPS:
+ case HEVC_NAL_SPS:
+ case HEVC_NAL_PPS:
+ case HEVC_NAL_SEI_PREFIX:
+ case HEVC_NAL_SEI_SUFFIX:
+ break;
+ default:
+ continue;
+ }
+ }
ret = decode_nal_unit(s, i);
if (ret < 0) {
@@ -3804,6 +3814,21 @@ static int decode_nal_units(HEVCContext *s, const
uint8_t *buf, int length)
}
}
+ /* All frames were discarded, but the parameter sets were parsed:
+ * export the stream parameters from the first SPS as the extradata
+ * path does, so skip_frame fills the parameters without decoding. */
+ if (s->avctx->skip_frame >= AVDISCARD_ALL &&
+ s->avctx->pix_fmt == AV_PIX_FMT_NONE) {
+ for (int i = 0; i < HEVC_MAX_SPS_COUNT; i++)
+ if (s->ps.sps_list[i]) {
+ export_stream_params(s, s->ps.sps_list[i]);
+ break;
+ }
+ ret = export_stream_params_from_sei(s);
+ if (ret < 0)
+ goto fail;
+ }
+
fail:
for (int i = 0; i < FF_ARRAY_ELEMS(s->layers); i++) {
HEVCLayerContext *l = &s->layers[i];
@@ -4272,6 +4297,7 @@ const FFCodec ff_hevc_decoder = {
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY |
AV_CODEC_CAP_SLICE_THREADS |
AV_CODEC_CAP_FRAME_THREADS,
.caps_internal = FF_CODEC_CAP_EXPORTS_CROPPING |
+ FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM |
FF_CODEC_CAP_USES_PROGRESSFRAMES |
FF_CODEC_CAP_INIT_CLEANUP,
.p.profiles = NULL_IF_CONFIG_SMALL(ff_hevc_profiles),
--
2.52.0
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