avcodec/ffv1: Only allocate ThreadFrames for the decoder

The FFV1 decoder only uses the last frame's data to conceal
errors. The encoder does not have this problem and therefore
only uses the current frame and none of the ThreadFrames.
So only allocate them for the decoder.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/ffv1.c

@@ -43,11 +43,6 @@ av_cold int ff_ffv1_common_init(AVCodecContext *avctx)
     s->avctx = avctx;
     s->flags = avctx->flags;
 
-    s->picture.f = av_frame_alloc();
-    s->last_picture.f = av_frame_alloc();
-    if (!s->picture.f || !s->last_picture.f)
-        return AVERROR(ENOMEM);
-
     s->width  = avctx->width;
     s->height = avctx->height;
 
@@ -198,14 +193,6 @@ av_cold int ff_ffv1_close(AVCodecContext *avctx)
     FFV1Context *s = avctx->priv_data;
     int i, j;
 
-    if (s->picture.f)
-        ff_thread_release_ext_buffer(avctx, &s->picture);
-    av_frame_free(&s->picture.f);
-
-    if (s->last_picture.f)
-        ff_thread_release_ext_buffer(avctx, &s->last_picture);
-    av_frame_free(&s->last_picture.f);
-
     for (j = 0; j < s->max_slice_count; j++) {
         FFV1Context *fs = s->slice_context[j];
         for (i = 0; i < s->plane_count; i++) {

libavcodec/ffv1dec.c

@@ -823,6 +823,11 @@ static av_cold int decode_init(AVCodecContext *avctx)
     if ((ret = ff_ffv1_common_init(avctx)) < 0)
         return ret;
 
+    f->picture.f      = av_frame_alloc();
+    f->last_picture.f = av_frame_alloc();
+    if (!f->picture.f || !f->last_picture.f)
+        return AVERROR(ENOMEM);
+
     if (avctx->extradata_size > 0 && (ret = read_extra_header(f)) < 0)
         return ret;
 
@@ -1068,6 +1073,22 @@ static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
 }
 #endif
 
+static av_cold int ffv1_decode_close(AVCodecContext *avctx)
+{
+    FFV1Context *const s = avctx->priv_data;
+
+    if (s->picture.f) {
+        ff_thread_release_ext_buffer(avctx, &s->picture);
+        av_frame_free(&s->picture.f);
+    }
+
+    if (s->last_picture.f) {
+        ff_thread_release_ext_buffer(avctx, &s->last_picture);
+        av_frame_free(&s->last_picture.f);
+    }
+    return ff_ffv1_close(avctx);
+}
+
 const FFCodec ff_ffv1_decoder = {
     .p.name         = "ffv1",
     CODEC_LONG_NAME("FFmpeg video codec #1"),
@@ -1075,7 +1096,7 @@ const FFCodec ff_ffv1_decoder = {
     .p.id           = AV_CODEC_ID_FFV1,
     .priv_data_size = sizeof(FFV1Context),
     .init           = decode_init,
-    .close          = ff_ffv1_close,
+    .close          = ffv1_decode_close,
     FF_CODEC_DECODE_CB(decode_frame),
     UPDATE_THREAD_CONTEXT(update_thread_context),
     .p.capabilities = AV_CODEC_CAP_DR1 /*| AV_CODEC_CAP_DRAW_HORIZ_BAND*/ |