vd_lavc: reduce hardware decoder mid-stream reinitializations

Instead of doing it on every seek (libavcodec calls get_format on every
seek), reinitialize the decoder only if the video resolution changes.

Note that this may be relatively naive, since we e.g. (or: in
particular) don't check for profile changes. But it's not worse than the
state before the get_format change, and at least it paints over the
current vaapi breakage (issue #646).

1 files changed, 6 insertions, 1 deletions

diff --git a/video/decode/vd_lavc.c b/video/decode/vd_lavc.c
index b49f3c6c44..4914d04f20 100644
--- a/video/decode/vd_lavc.c
+++ b/video/decode/vd_lavc.c
@@ -465,10 +465,15 @@ static enum AVPixelFormat get_format_hwdec(struct AVCodecContext *avctx,
     if (ctx->hwdec->image_format) {
         for (int i = 0; fmt[i] != AV_PIX_FMT_NONE; i++) {
             if (ctx->hwdec->image_format == pixfmt2imgfmt(fmt[i])) {
+                // There could be more reasons for a change, e.g. profile change.
+                bool change =
+                    ctx->hwdec_w != avctx->width ||
+                    ctx->hwdec_h != avctx->height ||
+                    ctx->hwdec_fmt != ctx->hwdec->image_format;
                 ctx->hwdec_w = avctx->width;
                 ctx->hwdec_h = avctx->height;
                 ctx->hwdec_fmt = ctx->hwdec->image_format;
-                if (ctx->hwdec->init_decoder) {
+                if (ctx->hwdec->init_decoder && change) {
                     if (ctx->hwdec->init_decoder(ctx, ctx->hwdec_fmt,
                                                  ctx->hwdec_w, ctx->hwdec_h) < 0)
                     {