Enable multi-threaded decoding with FFmpeg (helps with #1887).

diff --git a/src/lib/ffmpeg.cc b/src/lib/ffmpeg.cc
index 0e70d9c6f89350f12e5e1ffba1573f2d3af5aed2..f8398763e8185c59b096a7c9484844dedc5400a0 100644 (file)
--- a/src/lib/ffmpeg.cc
+++ b/src/lib/ffmpeg.cc
@@ -203,6 +203,9 @@ DCPOMATIC_DISABLE_WARNINGS
        for (uint32_t i = 0; i < _format_context->nb_streams; ++i) {
                auto context = _format_context->streams[i]->codec;
 
+               context->thread_count = 8;
+               context->thread_type = FF_THREAD_FRAME | FF_THREAD_SLICE;
+
                AVCodec* codec = avcodec_find_decoder (context->codec_id);
                if (codec) {