[FFmpeg-devel] [PR] avcodec/lcevc: attach a reference to the source frame to each passed in base picture (PR #21423)

[James Almer via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>]

PR #21423 opened by James Almer (jamrial)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21423
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21423.patch

This way we can ensure a frame reference will always exists for as long as the external library needs the base picture.


>From 644f1eaa829956060c2cf589fc7ddee9599a21ca Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Wed, 7 Jan 2026 12:16:27 -0300
Subject: [PATCH] avcodec/lcevc: attach a reference to the source frame to each
 passed in base picture

This way we can ensure a frame reference will always exists for as long as the
external library needs the base picture.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/lcevcdec.c | 46 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 37 insertions(+), 9 deletions(-)

diff --git a/libavcodec/lcevcdec.c b/libavcodec/lcevcdec.c
index 4f6d793625..865903bbd9 100644
--- a/libavcodec/lcevcdec.c
+++ b/libavcodec/lcevcdec.c
@@ -110,6 +110,7 @@ static int lcevc_send_frame(void *logctx, FFLCEVCFrame *frame_ctx, const AVFrame
 {
     FFLCEVCContext *lcevc = frame_ctx->lcevc;
     const AVFrameSideData *sd = av_frame_get_side_data(in, AV_FRAME_DATA_LCEVC);
+    AVFrame *opaque;
     LCEVC_PictureHandle picture;
     LCEVC_ReturnCode res;
     int ret = 0;
@@ -125,9 +126,23 @@ static int lcevc_send_frame(void *logctx, FFLCEVCFrame *frame_ctx, const AVFrame
     if (ret < 0)
         return ret;
 
+    opaque = av_frame_clone(in);
+    if (!opaque) {
+        LCEVC_FreePicture(lcevc->decoder, picture);
+        return AVERROR(ENOMEM);
+    }
+
+    res = LCEVC_SetPictureUserData(lcevc->decoder, picture, opaque);
+    if (res != LCEVC_Success) {
+        LCEVC_FreePicture(lcevc->decoder, picture);
+        av_frame_free(&opaque);
+        return AVERROR_EXTERNAL;
+    }
+
     res = LCEVC_SendDecoderBase(lcevc->decoder, in->pts, picture, -1, NULL);
     if (res != LCEVC_Success) {
         LCEVC_FreePicture(lcevc->decoder, picture);
+        av_frame_free(&opaque);
         return AVERROR_EXTERNAL;
     }
 
@@ -184,18 +199,13 @@ static int generate_output(void *logctx, FFLCEVCFrame *frame_ctx, AVFrame *out)
     return 0;
 }
 
-static int lcevc_receive_frame(void *logctx, FFLCEVCFrame *frame_ctx, AVFrame *out)
+static int lcevc_flush_pictures(FFLCEVCContext *lcevc)
 {
-    FFLCEVCContext *lcevc = frame_ctx->lcevc;
     LCEVC_PictureHandle picture;
     LCEVC_ReturnCode res;
-    int ret;
-
-    ret = generate_output(logctx, frame_ctx, out);
-    if (ret < 0)
-        return ret;
 
     while (1) {
+        AVFrame *base = NULL;
         res = LCEVC_ReceiveDecoderBase (lcevc->decoder, &picture);
         if (res != LCEVC_Success && res != LCEVC_Again)
             return AVERROR_EXTERNAL;
@@ -203,6 +213,9 @@ static int lcevc_receive_frame(void *logctx, FFLCEVCFrame *frame_ctx, AVFrame *o
         if (res == LCEVC_Again)
             break;
 
+        LCEVC_GetPictureUserData(lcevc->decoder, picture, (void **)&base);
+        av_frame_free(&base);
+
         res = LCEVC_FreePicture(lcevc->decoder, picture);
         if (res != LCEVC_Success)
             return AVERROR_EXTERNAL;
@@ -211,6 +224,18 @@ static int lcevc_receive_frame(void *logctx, FFLCEVCFrame *frame_ctx, AVFrame *o
     return 0;
 }
 
+static int lcevc_receive_frame(void *logctx, FFLCEVCFrame *frame_ctx, AVFrame *out)
+{
+    FFLCEVCContext *lcevc = frame_ctx->lcevc;
+    int ret;
+
+    ret = generate_output(logctx, frame_ctx, out);
+    if (ret < 0)
+        return ret;
+
+    return lcevc_flush_pictures(lcevc);
+}
+
 static void event_callback(LCEVC_DecoderHandle dec, LCEVC_Event event,
     LCEVC_PictureHandle pic, const LCEVC_DecodeInformation *info,
     const uint8_t *data, uint32_t size, void *logctx)
@@ -227,8 +252,11 @@ static void event_callback(LCEVC_DecoderHandle dec, LCEVC_Event event,
 static void lcevc_free(AVRefStructOpaque unused, void *obj)
 {
     FFLCEVCContext *lcevc = obj;
-    if (lcevc->initialized)
+    if (lcevc->initialized) {
+        LCEVC_FlushDecoder(lcevc->decoder);
+        lcevc_flush_pictures(lcevc);
         LCEVC_DestroyDecoder(lcevc->decoder);
+    }
     memset(lcevc, 0, sizeof(*lcevc));
 }
 
@@ -277,7 +305,7 @@ int ff_lcevc_process(void *logctx, AVFrame *frame)
     if (ret)
         return ret < 0 ? ret : 0;
 
-    lcevc_receive_frame(logctx, frame_ctx, frame);
+    ret = lcevc_receive_frame(logctx, frame_ctx, frame);
     if (ret < 0)
         return ret;
 
-- 
2.49.1

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