[FFmpeg-devel] [RFC PATCH 3/4] avcodec/hevcdec: add nuh_layer_id option

[Zhao Zhili]

From: Zhao Zhili <zhilizhao at tencent.com>

It can be used to decode selected independent non-base layer. One
use case is alpha layer decoding.

Signed-off-by: Zhao Zhili <zhilizhao at tencent.com>
---
 libavcodec/hevcdec.c | 20 +++++++++++++++++++-
 libavcodec/version.h |  2 +-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index 567e8d81d4..9641922834 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -3216,7 +3216,8 @@ static int decode_nal_units(HEVCContext *s, const uint8_t *buf, int length)
 
         if (s->avctx->skip_frame >= AVDISCARD_ALL ||
             (s->avctx->skip_frame >= AVDISCARD_NONREF
-            && ff_hevc_nal_is_nonref(nal->type)) || nal->nuh_layer_id > 0)
+            && ff_hevc_nal_is_nonref(nal->type)) ||
+            nal->nuh_layer_id != s->nuh_layer_id)
             continue;
 
         ret = decode_nal_unit(s, nal);
@@ -3637,6 +3638,21 @@ static av_cold int hevc_decode_init(AVCodecContext *avctx)
     HEVCContext *s = avctx->priv_data;
     int ret;
 
+    if (s->nuh_layer_id > 0) {
+        if (avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL) {
+            av_log(avctx, AV_LOG_ERROR,
+                    "Decode selected nuh_layer_id is undef development. "
+                    "Use -strict -2 to use it anyway.\n");
+            return AVERROR(EINVAL);
+        }
+
+        if (avctx->hwaccel) {
+            av_log(avctx, AV_LOG_ERROR,
+                    "Decode selected nuh_layer_id doesn't work with hwaccel.\n");
+            return AVERROR(EINVAL);
+        }
+    }
+
     if (avctx->active_thread_type & FF_THREAD_SLICE) {
         s->threads_number = avctx->thread_count;
         ret = ff_slice_thread_init_progress(avctx);
@@ -3691,6 +3707,8 @@ static const AVOption options[] = {
         AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, PAR },
     { "strict-displaywin", "stricly apply default display window size", OFFSET(apply_defdispwin),
         AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, PAR },
+    { "nuh_layer_id", "Select which nuh_layer_id to decode (only works with INBL)", OFFSET(nuh_layer_id),
+        AV_OPT_TYPE_INT,  {.i64 = 0}, 0, 62, PAR },
     { NULL },
 };
 
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 6b8a1dbb79..15f7c3fe3d 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -30,7 +30,7 @@
 #include "version_major.h"
 
 #define LIBAVCODEC_VERSION_MINOR  56
-#define LIBAVCODEC_VERSION_MICRO 100
+#define LIBAVCODEC_VERSION_MICRO 101
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \
-- 
2.25.1