- Added MP3 encoding through libmp3lame contributed by Lennert Buytenhek.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@325 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/mp3lameaudio.c

+/*
+ * Interface to libmp3lame for mp3 encoding
+ * Copyright (c) 2002 Lennert Buytenhek <buytenh@gnu.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "avcodec.h"
+#include <math.h>
+#include "mpegaudio.h"
+#include <lame/lame.h>
+
+typedef struct Mp3AudioContext {
+	lame_global_flags *gfp;
+	int first_frame;
+	int stereo;
+} Mp3AudioContext;
+
+
+static int MP3lame_encode_init(AVCodecContext *avctx)
+{
+	Mp3AudioContext *s = avctx->priv_data;
+
+	if (avctx->channels > 2)
+		return -1;
+
+	s->first_frame = 1;
+	s->stereo = avctx->channels > 1 ? 1 : 0;
+
+	if ((s->gfp = lame_init()) == NULL)
+		goto err;
+	lame_set_in_samplerate(s->gfp, avctx->sample_rate);
+	lame_set_num_channels(s->gfp, avctx->channels);
+	/* lame 3.91 dies on quality != 5 */
+	lame_set_quality(s->gfp, 5);
+	/* lame 3.91 doesn't work in mono */
+	lame_set_mode(s->gfp, JOINT_STEREO);
+	lame_set_brate(s->gfp, avctx->bit_rate/1000);
+	if (lame_init_params(s->gfp) < 0)
+		goto err_close;
+
+	avctx->frame_size = MPA_FRAME_SIZE;
+	avctx->key_frame = 1;
+
+	return 0;
+
+err_close:
+	lame_close(s->gfp);
+err:
+	return -1;
+}
+
+int MP3lame_encode_frame(AVCodecContext *avctx,
+                     unsigned char *frame, int buf_size, void *data)
+{
+	Mp3AudioContext *s = avctx->priv_data;
+	int num;
+
+	/* lame 3.91 dies on '1-channel interleaved' data */
+	if (s->stereo) {
+		num = lame_encode_buffer_interleaved(s->gfp, data,
+			MPA_FRAME_SIZE, frame, buf_size);
+	} else {
+		num = lame_encode_buffer(s->gfp, data, data, MPA_FRAME_SIZE,
+			frame, buf_size);
+	}
+
+	/* lame 3.91 outputs the first frame as garbage */
+	if (s->first_frame)
+		s->first_frame = num = 0;
+
+	return num;
+}
+
+int MP3lame_encode_close(AVCodecContext *avctx)
+{
+	Mp3AudioContext *s = avctx->priv_data;
+
+	lame_close(s->gfp);
+	return 0;
+}
+
+
+AVCodec mp3lame_encoder = {
+    "mp3",
+    CODEC_TYPE_AUDIO,
+    CODEC_ID_MP3LAME,
+    sizeof(Mp3AudioContext),
+    MP3lame_encode_init,
+    MP3lame_encode_frame,
+    MP3lame_encode_close
+};