lavc: add null codecs

They discard all input without ever returning any output. Useful for
development.

1 files changed, 97 insertions, 0 deletions

diff --git a/libavcodec/null.c b/libavcodec/null.c
new file mode 100644
index 0000000000..d8e334437c
--- /dev/null
+++ b/libavcodec/null.c
@@ -0,0 +1,97 @@
+/*
+ * Null codecs
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config_components.h"
+
+#include "codec_internal.h"
+#include "decode.h"
+#include "encode.h"
+
+#if CONFIG_VNULL_DECODER || CONFIG_ANULL_DECODER
+static int null_decode(AVCodecContext *avctx, AVFrame *frame,
+                       int *got_frame, AVPacket *avpkt)
+{
+    *got_frame = 0;
+    return avpkt->size;
+}
+
+#if CONFIG_VNULL_DECODER
+const FFCodec ff_vnull_decoder = {
+    .p.name         = "vnull",
+    CODEC_LONG_NAME("null video"),
+    .p.type         = AVMEDIA_TYPE_VIDEO,
+    .p.id           = AV_CODEC_ID_VNULL,
+    .p.capabilities = AV_CODEC_CAP_DR1,
+    FF_CODEC_DECODE_CB(null_decode),
+};
+#endif
+
+#if CONFIG_ANULL_DECODER
+const FFCodec ff_anull_decoder = {
+    .p.name         = "anull",
+    CODEC_LONG_NAME("null audio"),
+    .p.type         = AVMEDIA_TYPE_AUDIO,
+    .p.id           = AV_CODEC_ID_ANULL,
+    .p.capabilities = AV_CODEC_CAP_DR1,
+    FF_CODEC_DECODE_CB(null_decode),
+};
+#endif
+
+#endif
+
+#if CONFIG_VNULL_ENCODER || CONFIG_ANULL_ENCODER
+static int null_encode(AVCodecContext *avctx, AVPacket *pkt,
+                       const AVFrame *frame, int *got_packet)
+{
+    *got_packet = 0;
+    return 0;
+}
+
+#if CONFIG_VNULL_ENCODER
+const FFCodec ff_vnull_encoder = {
+    .p.name         = "vnull",
+    CODEC_LONG_NAME("null video"),
+    .p.type         = AVMEDIA_TYPE_VIDEO,
+    .p.id           = AV_CODEC_ID_VNULL,
+    FF_CODEC_ENCODE_CB(null_encode),
+};
+#endif
+
+#if CONFIG_ANULL_ENCODER
+const FFCodec ff_anull_encoder = {
+    .p.name         = "anull",
+    CODEC_LONG_NAME("null audio"),
+    .p.type         = AVMEDIA_TYPE_AUDIO,
+    .p.id           = AV_CODEC_ID_ANULL,
+    .p.capabilities = AV_CODEC_CAP_VARIABLE_FRAME_SIZE,
+    .p.sample_fmts  = (const enum AVSampleFormat[]){
+        AV_SAMPLE_FMT_U8,  AV_SAMPLE_FMT_U8P,
+        AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16P,
+        AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P,
+        AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_S64P,
+        AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLTP,
+        AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBLP,
+        AV_SAMPLE_FMT_NONE,
+    },
+    FF_CODEC_ENCODE_CB(null_encode),
+};
+#endif
+
+#endif