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-rw-r--r--mpegmux.c301
1 files changed, 301 insertions, 0 deletions
diff --git a/mpegmux.c b/mpegmux.c
new file mode 100644
index 0000000000..fff01525a5
--- /dev/null
+++ b/mpegmux.c
@@ -0,0 +1,301 @@
+/*
+ * Output a MPEG1 multiplexed video/audio stream
+ * Copyright (c) 2000 Gerard Lantau.
+ *
+ * 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 <stdlib.h>
+#include <stdio.h>
+#include <netinet/in.h>
+#include <linux/videodev.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <getopt.h>
+
+#include "mpegenc.h"
+#include "mpegvideo.h"
+#include "mpegaudio.h"
+
+#define MAX_PAYLOAD_SIZE 4096
+#define NB_STREAMS 2
+
+typedef struct {
+ UINT8 buffer[MAX_PAYLOAD_SIZE];
+ int buffer_ptr;
+ UINT8 id;
+ int max_buffer_size;
+ int packet_number;
+ AVEncodeContext *enc;
+ float pts;
+} StreamInfo;
+
+typedef struct {
+ int packet_size; /* required packet size */
+ int packet_number;
+ int pack_header_freq; /* frequency (in packets^-1) at which we send pack headers */
+ int system_header_freq;
+ int mux_rate; /* bitrate in units of 50 bytes/s */
+ /* stream info */
+ int nb_streams;
+ StreamInfo streams[NB_STREAMS];
+ AVFormatContext *ctx;
+} MpegMuxContext;
+
+#define PACK_START_CODE ((unsigned int)0x000001ba)
+#define SYSTEM_HEADER_START_CODE ((unsigned int)0x000001bb)
+#define PACKET_START_CODE_MASK ((unsigned int)0xffffff00)
+#define PACKET_START_CODE_PREFIX ((unsigned int)0x00000100)
+#define ISO_11172_END_CODE ((unsigned int)0x000001b9)
+
+#define AUDIO_ID 0xc0
+#define VIDEO_ID 0xe0
+
+static int put_pack_header(MpegMuxContext *s, UINT8 *buf, long long timestamp)
+{
+ PutBitContext pb;
+
+ init_put_bits(&pb, buf, 128, NULL, NULL);
+
+ put_bits(&pb, 32, PACK_START_CODE);
+ put_bits(&pb, 4, 0x2);
+ put_bits(&pb, 3, (timestamp >> 30) & 0x07);
+ put_bits(&pb, 1, 1);
+ put_bits(&pb, 15, (timestamp >> 15) & 0x7fff);
+ put_bits(&pb, 1, 1);
+ put_bits(&pb, 15, (timestamp) & 0x7fff);
+ put_bits(&pb, 1, 1);
+ put_bits(&pb, 1, 1);
+ put_bits(&pb, 22, s->mux_rate);
+
+ flush_put_bits(&pb);
+ return pb.buf_ptr - pb.buf;
+}
+
+static int put_system_header(MpegMuxContext *s, UINT8 *buf)
+{
+ int audio_bound, video_bound;
+ int size, rate_bound, i;
+ PutBitContext pb;
+
+ init_put_bits(&pb, buf, 128, NULL, NULL);
+
+ put_bits(&pb, 32, SYSTEM_HEADER_START_CODE);
+ put_bits(&pb, 16, 0);
+ put_bits(&pb, 1, 1);
+
+ rate_bound = s->mux_rate; /* maximum bit rate of the multiplexed stream */
+ put_bits(&pb, 22, rate_bound);
+ put_bits(&pb, 1, 1); /* marker */
+ audio_bound = 1; /* at most one audio stream */
+ put_bits(&pb, 6, audio_bound);
+
+ put_bits(&pb, 1, 0); /* variable bitrate */
+ put_bits(&pb, 1, 0); /* non constrainted bit stream */
+
+ put_bits(&pb, 1, 1); /* audio locked */
+ put_bits(&pb, 1, 1); /* video locked */
+ put_bits(&pb, 1, 1); /* marker */
+
+ video_bound = 1; /* at most one video stream */
+ put_bits(&pb, 5, video_bound);
+ put_bits(&pb, 8, 0xff); /* reserved byte */
+
+ /* audio stream info */
+ for(i=0;i<s->nb_streams;i++) {
+ put_bits(&pb, 8, s->streams[i].id); /* stream ID */
+ put_bits(&pb, 2, 3);
+ put_bits(&pb, 1, 1); /* buffer bound scale = 1024 */
+ put_bits(&pb, 13, s->streams[i].max_buffer_size); /* max buffer size */
+ }
+ /* no more streams */
+ put_bits(&pb, 1, 0);
+ flush_put_bits(&pb);
+ size = pb.buf_ptr - pb.buf;
+ /* patch packet size */
+ buf[4] = (size - 6) >> 8;
+ buf[5] = (size - 6) & 0xff;
+
+ return size;
+}
+
+/* Format a packet header for a total size of 'total_size'. Return the
+ header size */
+static int put_packet_header(MpegMuxContext *s,
+ int id, long long timestamp,
+ UINT8 *buffer, int total_size)
+{
+ UINT8 *buf_ptr;
+ PutBitContext pb;
+ int size, payload_size;
+
+#if 0
+ printf("packet ID=%2x PTS=%0.3f size=%d\n",
+ id, timestamp / 90000.0, total_size);
+#endif
+
+ buf_ptr = buffer;
+
+ if ((s->packet_number % s->pack_header_freq) == 0) {
+ /* output pack and systems header */
+ size = put_pack_header(s, buf_ptr, timestamp);
+ buf_ptr += size;
+ if ((s->packet_number % s->system_header_freq) == 0) {
+ size = put_system_header(s, buf_ptr);
+ buf_ptr += size;
+ }
+ }
+
+ payload_size = total_size - ((buf_ptr - buffer) + 6 + 5);
+ /* packet header */
+ init_put_bits(&pb, buf_ptr, 128, NULL, NULL);
+
+ put_bits(&pb, 32, PACKET_START_CODE_PREFIX + id);
+ put_bits(&pb, 16, payload_size + 5);
+ /* presentation time stamp */
+ put_bits(&pb, 4, 0x02);
+ put_bits(&pb, 3, (timestamp >> 30) & 0x07);
+ put_bits(&pb, 1, 1);
+ put_bits(&pb, 15, (timestamp >> 15) & 0x7fff);
+ put_bits(&pb, 1, 1);
+ put_bits(&pb, 15, (timestamp) & 0x7fff);
+ put_bits(&pb, 1, 1);
+
+ flush_put_bits(&pb);
+
+ s->packet_number++;
+ return pb.buf_ptr - buffer;
+}
+
+int mpeg_mux_init(AVFormatContext *ctx)
+{
+ MpegMuxContext *s;
+ int bitrate, i;
+
+ s = malloc(sizeof(MpegMuxContext));
+ if (!s)
+ return -1;
+ memset(s, 0, sizeof(MpegMuxContext));
+ ctx->priv_data = s;
+ s->ctx = ctx;
+ s->packet_number = 0;
+
+ /* XXX: hardcoded */
+ s->packet_size = 2048;
+ s->nb_streams = 2;
+ s->streams[0].id = AUDIO_ID;
+ s->streams[0].max_buffer_size = 10; /* in KBytes */
+ s->streams[0].enc = ctx->audio_enc;
+ s->streams[1].id = VIDEO_ID;
+ s->streams[1].max_buffer_size = 50; /* in KBytes */
+ s->streams[1].enc = ctx->video_enc;
+
+ /* we increase slightly the bitrate to take into account the
+ headers. XXX: compute it exactly */
+ bitrate = 2000;
+ for(i=0;i<s->nb_streams;i++) {
+ bitrate += s->streams[i].enc->bit_rate;
+ }
+ s->mux_rate = (bitrate + (8 * 50) - 1) / (8 * 50);
+ /* every 2 seconds */
+ s->pack_header_freq = 2 * bitrate / s->packet_size / 8;
+ /* every 10 seconds */
+ s->system_header_freq = s->pack_header_freq * 5;
+
+ for(i=0;i<NB_STREAMS;i++) {
+ s->streams[i].buffer_ptr = 0;
+ s->streams[i].packet_number = 0;
+ s->streams[i].pts = 0;
+ }
+ return 0;
+}
+
+int mpeg_mux_end(AVFormatContext *ctx)
+{
+ PutBitContext pb;
+ UINT8 buffer[128];
+
+ /* write the end header */
+ init_put_bits(&pb, buffer, sizeof(buffer), NULL, NULL);
+ put_bits(&pb, 32, ISO_11172_END_CODE);
+
+ put_buffer(&ctx->pb, buffer, pb.buf_ptr - buffer);
+ put_flush_packet(&ctx->pb);
+ return 0;
+}
+
+static void write_stream(MpegMuxContext *s, StreamInfo *stream, UINT8 *buf, int size)
+{
+ int len, len1, header_size;
+ long long pts;
+ while (size > 0) {
+ if (stream->buffer_ptr == 0) {
+ pts = stream->pts * 90000.0;
+ header_size = put_packet_header(s, stream->id, pts, stream->buffer, s->packet_size);
+ stream->buffer_ptr = header_size;
+ }
+ len = size;
+ len1 = s->packet_size - stream->buffer_ptr;
+ if (len > len1)
+ len = len1;
+ memcpy(stream->buffer + stream->buffer_ptr, buf, len);
+ stream->buffer_ptr += len;
+ if (stream->buffer_ptr == s->packet_size) {
+ /* output the packet */
+ put_buffer(&s->ctx->pb, stream->buffer, s->packet_size);
+ put_flush_packet(&s->ctx->pb);
+ stream->buffer_ptr = 0;
+ stream->packet_number++;
+ }
+ buf += len;
+ size -= len;
+ }
+}
+
+static int mpeg_mux_write_audio(AVFormatContext *ctx, UINT8 *buf, int size)
+{
+ MpegMuxContext *s = ctx->priv_data;
+
+ write_stream(s, &s->streams[0], buf, size);
+ s->streams[0].pts += (float)s->streams[0].enc->frame_size / s->streams[0].enc->rate;
+ return 0;
+}
+
+int mpeg_mux_write_video(AVFormatContext *ctx, UINT8 *buf, int size)
+{
+ MpegMuxContext *s = ctx->priv_data;
+
+ write_stream(s, &s->streams[1], buf, size);
+ s->streams[1].pts += 1.0 / (float)s->streams[1].enc->rate;
+
+ return 0;
+}
+
+AVFormat mpeg_mux_format = {
+ "mpeg1",
+ "MPEG1 multiplex format",
+ "video/mpeg",
+ "mpg,mpeg",
+ CODEC_ID_MP2,
+ CODEC_ID_MPEG1VIDEO,
+ mpeg_mux_init,
+ mpeg_mux_write_audio,
+ mpeg_mux_write_video,
+ mpeg_mux_end,
+};
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