[FFmpeg-devel] [PATCH] avcodec/lcevcdec: fix input dimensions for the base picture (PR #21269)

[FFmpeg-devel] [PATCH] avcodec/lcevcdec: fix input dimensions for the base picture (PR #21269)

[James Almer via ffmpeg-devel]

PR #21269 opened by James Almer (jamrial)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21269
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21269.patch


>From 6bef7777d6651328b80d70490ac1456eeb466657 Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Mon, 22 Dec 2025 21:53:47 -0300
Subject: [PATCH 1/3] avcodec/lcevcdec: avoid copying the input frame

Based on the lcevc filter implementation.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/lcevcdec.c | 37 +++++++------------------------------
 1 file changed, 7 insertions(+), 30 deletions(-)

diff --git a/libavcodec/lcevcdec.c b/libavcodec/lcevcdec.c
index f55f55a03f..bccd524bf5 100644
--- a/libavcodec/lcevcdec.c
+++ b/libavcodec/lcevcdec.c
@@ -49,10 +49,7 @@ static int alloc_base_frame(void *logctx, FFLCEVCContext *lcevc,
 {
     LCEVC_PictureDesc desc;
     LCEVC_ColorFormat fmt = map_format(frame->format);
-    LCEVC_PictureLockHandle lock;
-    uint8_t *data[4] = { NULL };
-    int linesizes[4] = { 0 };
-    uint32_t planes;
+    LCEVC_PicturePlaneDesc planes[AV_VIDEO_MAX_PLANES] = { 0 };
     LCEVC_ReturnCode res;
 
     res = LCEVC_DefaultPictureDesc(&desc, fmt, frame->width, frame->height);
@@ -66,36 +63,16 @@ static int alloc_base_frame(void *logctx, FFLCEVCContext *lcevc,
     desc.sampleAspectRatioNum  = frame->sample_aspect_ratio.num;
     desc.sampleAspectRatioDen  = frame->sample_aspect_ratio.den;
 
+    for (int i = 0; i < AV_VIDEO_MAX_PLANES; i++) {
+        planes[i].firstSample = frame->data[i];
+        planes[i].rowByteStride = frame->linesize[i];
+    }
+
     /* Allocate LCEVC Picture */
-    res = LCEVC_AllocPicture(lcevc->decoder, &desc, picture);
+    res = LCEVC_AllocPictureExternal(lcevc->decoder, &desc, NULL, planes, picture);
     if (res != LCEVC_Success) {
         return AVERROR_EXTERNAL;
     }
-    res = LCEVC_LockPicture(lcevc->decoder, *picture, LCEVC_Access_Write, &lock);
-    if (res != LCEVC_Success)
-        return AVERROR_EXTERNAL;
-
-    res = LCEVC_GetPicturePlaneCount(lcevc->decoder, *picture, &planes);
-    if (res != LCEVC_Success)
-        return AVERROR_EXTERNAL;
-
-    for (unsigned i = 0; i < planes; i++) {
-        LCEVC_PicturePlaneDesc plane;
-
-        res = LCEVC_GetPictureLockPlaneDesc(lcevc->decoder, lock, i, &plane);
-        if (res != LCEVC_Success)
-            return AVERROR_EXTERNAL;
-
-        data[i] = plane.firstSample;
-        linesizes[i] = plane.rowByteStride;
-    }
-
-    av_image_copy2(data, linesizes, frame->data, frame->linesize,
-                   frame->format, frame->width, frame->height);
-
-    res = LCEVC_UnlockPicture(lcevc->decoder, lock);
-    if (res != LCEVC_Success)
-        return AVERROR_EXTERNAL;
 
     return 0;
 }
-- 
2.49.1


>From 6921861dd18345e762d59f1ee4b9d61683b3db32 Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Mon, 22 Dec 2025 21:54:43 -0300
Subject: [PATCH 2/3] avcodec/lcevcdec: fix input dimensions for the base
 picture

Fixes crashes with some samples.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/lcevcdec.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavcodec/lcevcdec.c b/libavcodec/lcevcdec.c
index bccd524bf5..179ebdd708 100644
--- a/libavcodec/lcevcdec.c
+++ b/libavcodec/lcevcdec.c
@@ -50,9 +50,11 @@ static int alloc_base_frame(void *logctx, FFLCEVCContext *lcevc,
     LCEVC_PictureDesc desc;
     LCEVC_ColorFormat fmt = map_format(frame->format);
     LCEVC_PicturePlaneDesc planes[AV_VIDEO_MAX_PLANES] = { 0 };
+    int width = frame->width - frame->crop_left - frame->crop_right;
+    int height = frame->height - frame->crop_top - frame->crop_bottom;
     LCEVC_ReturnCode res;
 
-    res = LCEVC_DefaultPictureDesc(&desc, fmt, frame->width, frame->height);
+    res = LCEVC_DefaultPictureDesc(&desc, fmt, width, height);
     if (res != LCEVC_Success)
         return AVERROR_EXTERNAL;
 
-- 
2.49.1


>From f2e0eb48594e83c3dbd026358afaabc9b9ed552c Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Mon, 22 Dec 2025 21:56:09 -0300
Subject: [PATCH 3/3] avcodec/lcevcdec: free pictures on error

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/lcevcdec.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/libavcodec/lcevcdec.c b/libavcodec/lcevcdec.c
index 179ebdd708..4f6d793625 100644
--- a/libavcodec/lcevcdec.c
+++ b/libavcodec/lcevcdec.c
@@ -126,8 +126,10 @@ static int lcevc_send_frame(void *logctx, FFLCEVCFrame *frame_ctx, const AVFrame
         return ret;
 
     res = LCEVC_SendDecoderBase(lcevc->decoder, in->pts, picture, -1, NULL);
-    if (res != LCEVC_Success)
+    if (res != LCEVC_Success) {
+        LCEVC_FreePicture(lcevc->decoder, picture);
         return AVERROR_EXTERNAL;
+    }
 
     memset(&picture, 0, sizeof(picture));
     ret = alloc_enhanced_frame(logctx, frame_ctx, &picture);
@@ -135,8 +137,10 @@ static int lcevc_send_frame(void *logctx, FFLCEVCFrame *frame_ctx, const AVFrame
         return ret;
 
     res = LCEVC_SendDecoderPicture(lcevc->decoder, picture);
-    if (res != LCEVC_Success)
+    if (res != LCEVC_Success) {
+        LCEVC_FreePicture(lcevc->decoder, picture);
         return AVERROR_EXTERNAL;
+    }
 
     return 0;
 }
@@ -154,8 +158,10 @@ static int generate_output(void *logctx, FFLCEVCFrame *frame_ctx, AVFrame *out)
         return AVERROR_EXTERNAL;
 
     res = LCEVC_GetPictureDesc(lcevc->decoder, picture, &desc);
-    if (res != LCEVC_Success)
+    if (res != LCEVC_Success) {
+        LCEVC_FreePicture(lcevc->decoder, picture);
         return AVERROR_EXTERNAL;
+    }
 
     out->crop_top = desc.cropTop;
     out->crop_bottom = desc.cropBottom;
-- 
2.49.1

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