lavc: add a header for internal generic-layer APIs

The goal is to distinguish between APIs provided by the generic layer to
individual codecs and APIs internal to the generic layer.

Start by moving ff_{decode,encode}_receive_frame() and
ff_{decode,encode}_preinit() into this new header, as those functions
are called from generic code and should not be visible to individual
codecs.

libavcodec/avcodec.c

@@ -34,6 +34,7 @@
 #include "libavutil/opt.h"
 #include "libavutil/thread.h"
 #include "avcodec.h"
+#include "avcodec_internal.h"
 #include "bsf.h"
 #include "codec_internal.h"
 #include "decode.h"

libavcodec/avcodec_internal.h

@@ -0,0 +1,53 @@
+/*
+ * 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
+ */
+
+/*
+ * APIs internal to the generic codec layer.
+ *
+ * MUST NOT be included by individual encoders or decoders.
+ */
+
+#ifndef AVCODEC_AVCODEC_INTERNAL_H
+#define AVCODEC_AVCODEC_INTERNAL_H
+
+struct AVCodecContext;
+struct AVFrame;
+
+/**
+ * avcodec_receive_frame() implementation for decoders.
+ */
+int ff_decode_receive_frame(struct AVCodecContext *avctx, struct AVFrame *frame);
+
+/**
+ * avcodec_receive_frame() implementation for encoders.
+ */
+int ff_encode_receive_frame(struct AVCodecContext *avctx, struct AVFrame *frame);
+
+/*
+ * Perform encoder initialization and validation.
+ * Called when opening the encoder, before the FFCodec.init() call.
+ */
+int ff_encode_preinit(struct AVCodecContext *avctx);
+
+/**
+ * Perform decoder initialization and validation.
+ * Called when opening the decoder, before the FFCodec.init() call.
+ */
+int ff_decode_preinit(struct AVCodecContext *avctx);
+
+#endif // AVCODEC_AVCODEC_INTERNAL_H

libavcodec/decode.c

@@ -41,6 +41,7 @@
 #include "libavutil/opt.h"
 
 #include "avcodec.h"
+#include "avcodec_internal.h"
 #include "bytestream.h"
 #include "bsf.h"
 #include "codec_internal.h"

libavcodec/decode.h

@@ -53,11 +53,6 @@ typedef struct FrameDecodeData {
     void (*hwaccel_priv_free)(void *priv);
 } FrameDecodeData;
 
-/**
- * avcodec_receive_frame() implementation for decoders.
- */
-int ff_decode_receive_frame(AVCodecContext *avctx, AVFrame *frame);
-
 /**
  * Called by decoders to get the next packet for decoding.
  *
@@ -99,12 +94,6 @@ int ff_attach_decode_data(AVFrame *frame);
  */
 int ff_copy_palette(void *dst, const AVPacket *src, void *logctx);
 
-/**
- * Perform decoder initialization and validation.
- * Called when opening the decoder, before the FFCodec.init() call.
- */
-int ff_decode_preinit(AVCodecContext *avctx);
-
 /**
  * Check that the provided frame dimensions are valid and set them on the codec
  * context.

libavcodec/encode.c

@@ -27,6 +27,7 @@
 #include "libavutil/samplefmt.h"
 
 #include "avcodec.h"
+#include "avcodec_internal.h"
 #include "codec_internal.h"
 #include "encode.h"
 #include "frame_thread_encoder.h"

libavcodec/encode.h

@@ -26,11 +26,6 @@
 #include "avcodec.h"
 #include "packet.h"
 
-/**
- * avcodec_receive_frame() implementation for encoders.
- */
-int ff_encode_receive_frame(AVCodecContext *avctx, AVFrame *frame);
-
 /**
  * Called by encoders to get the next frame for encoding.
  *
@@ -75,12 +70,6 @@ int ff_alloc_packet(AVCodecContext *avctx, AVPacket *avpkt, int64_t size);
 int ff_encode_reordered_opaque(AVCodecContext *avctx,
                                AVPacket *pkt, const AVFrame *frame);
 
-/*
- * Perform encoder initialization and validation.
- * Called when opening the encoder, before the FFCodec.init() call.
- */
-int ff_encode_preinit(AVCodecContext *avctx);
-
 int ff_encode_encode_cb(AVCodecContext *avctx, AVPacket *avpkt,
                         AVFrame *frame, int *got_packet);