split mpeg ps and variants muxer and demuxer, I'll clean more in a few minutes, lpcm freq tab is left static const in mpeg.h for now until we have more code in common

Originally committed as revision 9382 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 1297 insertions, 0 deletions

diff --git a/libavformat/mpegenc.c b/libavformat/mpegenc.c
new file mode 100644
index 0000000000..464a1f7bd7
--- /dev/null
+++ b/libavformat/mpegenc.c
@@ -0,0 +1,1297 @@
+/*
+ * MPEG1/2 muxer
+ * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
+ *
+ * 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 "avformat.h"
+#include "bitstream.h"
+#include "fifo.h"
+#include "mpeg.h"
+
+#define MAX_PAYLOAD_SIZE 4096
+//#define DEBUG_SEEK
+
+#undef NDEBUG
+#include <assert.h>
+
+typedef struct PacketDesc {
+    int64_t pts;
+    int64_t dts;
+    int size;
+    int unwritten_size;
+    int flags;
+    struct PacketDesc *next;
+} PacketDesc;
+
+typedef struct {
+    AVFifoBuffer fifo;
+    uint8_t id;
+    int max_buffer_size; /* in bytes */
+    int buffer_index;
+    PacketDesc *predecode_packet;
+    PacketDesc *premux_packet;
+    PacketDesc **next_packet;
+    int packet_number;
+    uint8_t lpcm_header[3];
+    int lpcm_align;
+    int bytes_to_iframe;
+    int align_iframe;
+    int64_t vobu_start_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 system_header_size;
+    int mux_rate; /* bitrate in units of 50 bytes/s */
+    /* stream info */
+    int audio_bound;
+    int video_bound;
+    int is_mpeg2;
+    int is_vcd;
+    int is_svcd;
+    int is_dvd;
+    int64_t last_scr; /* current system clock */
+
+    double vcd_padding_bitrate; //FIXME floats
+    int64_t vcd_padding_bytes_written;
+
+} MpegMuxContext;
+
+#ifdef CONFIG_MUXERS
+AVOutputFormat mpeg1system_muxer;
+AVOutputFormat mpeg1vcd_muxer;
+AVOutputFormat mpeg2vob_muxer;
+AVOutputFormat mpeg2svcd_muxer;
+AVOutputFormat mpeg2dvd_muxer;
+
+static int put_pack_header(AVFormatContext *ctx,
+                           uint8_t *buf, int64_t timestamp)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    PutBitContext pb;
+
+    init_put_bits(&pb, buf, 128);
+
+    put_bits(&pb, 32, PACK_START_CODE);
+    if (s->is_mpeg2) {
+        put_bits(&pb, 2, 0x1);
+    } else {
+        put_bits(&pb, 4, 0x2);
+    }
+    put_bits(&pb, 3, (uint32_t)((timestamp >> 30) & 0x07));
+    put_bits(&pb, 1, 1);
+    put_bits(&pb, 15, (uint32_t)((timestamp >> 15) & 0x7fff));
+    put_bits(&pb, 1, 1);
+    put_bits(&pb, 15, (uint32_t)((timestamp) & 0x7fff));
+    put_bits(&pb, 1, 1);
+    if (s->is_mpeg2) {
+        /* clock extension */
+        put_bits(&pb, 9, 0);
+    }
+    put_bits(&pb, 1, 1);
+    put_bits(&pb, 22, s->mux_rate);
+    put_bits(&pb, 1, 1);
+    if (s->is_mpeg2) {
+        put_bits(&pb, 1, 1);
+        put_bits(&pb, 5, 0x1f); /* reserved */
+        put_bits(&pb, 3, 0); /* stuffing length */
+    }
+    flush_put_bits(&pb);
+    return pbBufPtr(&pb) - pb.buf;
+}
+
+static int put_system_header(AVFormatContext *ctx, uint8_t *buf,int only_for_stream_id)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    int size, i, private_stream_coded, id;
+    PutBitContext pb;
+
+    init_put_bits(&pb, buf, 128);
+
+    put_bits(&pb, 32, SYSTEM_HEADER_START_CODE);
+    put_bits(&pb, 16, 0);
+    put_bits(&pb, 1, 1);
+
+    put_bits(&pb, 22, s->mux_rate); /* maximum bit rate of the multiplexed stream */
+    put_bits(&pb, 1, 1); /* marker */
+    if (s->is_vcd && only_for_stream_id==VIDEO_ID) {
+        /* This header applies only to the video stream (see VCD standard p. IV-7)*/
+        put_bits(&pb, 6, 0);
+    } else
+        put_bits(&pb, 6, s->audio_bound);
+
+    if (s->is_vcd) {
+        /* see VCD standard, p. IV-7*/
+        put_bits(&pb, 1, 0);
+        put_bits(&pb, 1, 1);
+    } else {
+        put_bits(&pb, 1, 0); /* variable bitrate*/
+        put_bits(&pb, 1, 0); /* non constrainted bit stream */
+    }
+
+    if (s->is_vcd || s->is_dvd) {
+        /* see VCD standard p IV-7 */
+        put_bits(&pb, 1, 1); /* audio locked */
+        put_bits(&pb, 1, 1); /* video locked */
+    } else {
+        put_bits(&pb, 1, 0); /* audio locked */
+        put_bits(&pb, 1, 0); /* video locked */
+    }
+
+    put_bits(&pb, 1, 1); /* marker */
+
+    if (s->is_vcd && only_for_stream_id==AUDIO_ID) {
+        /* This header applies only to the audio stream (see VCD standard p. IV-7)*/
+        put_bits(&pb, 5, 0);
+    } else
+        put_bits(&pb, 5, s->video_bound);
+
+    if (s->is_dvd) {
+        put_bits(&pb, 1, 0);    /* packet_rate_restriction_flag */
+        put_bits(&pb, 7, 0x7f); /* reserved byte */
+    } else
+        put_bits(&pb, 8, 0xff); /* reserved byte */
+
+    /* DVD-Video Stream_bound entries
+    id (0xB9) video, maximum P-STD for stream 0xE0. (P-STD_buffer_bound_scale = 1)
+    id (0xB8) audio, maximum P-STD for any MPEG audio (0xC0 to 0xC7) streams. If there are none set to 4096 (32x128). (P-STD_buffer_bound_scale = 0)
+    id (0xBD) private stream 1 (audio other than MPEG and subpictures). (P-STD_buffer_bound_scale = 1)
+    id (0xBF) private stream 2, NAV packs, set to 2x1024. */
+    if (s->is_dvd) {
+
+        int P_STD_max_video = 0;
+        int P_STD_max_mpeg_audio = 0;
+        int P_STD_max_mpeg_PS1 = 0;
+
+        for(i=0;i<ctx->nb_streams;i++) {
+            StreamInfo *stream = ctx->streams[i]->priv_data;
+
+            id = stream->id;
+            if (id == 0xbd && stream->max_buffer_size > P_STD_max_mpeg_PS1) {
+                P_STD_max_mpeg_PS1 = stream->max_buffer_size;
+            } else if (id >= 0xc0 && id <= 0xc7 && stream->max_buffer_size > P_STD_max_mpeg_audio) {
+                P_STD_max_mpeg_audio = stream->max_buffer_size;
+            } else if (id == 0xe0 && stream->max_buffer_size > P_STD_max_video) {
+                P_STD_max_video = stream->max_buffer_size;
+            }
+        }
+
+        /* video */
+        put_bits(&pb, 8, 0xb9); /* stream ID */
+        put_bits(&pb, 2, 3);
+        put_bits(&pb, 1, 1);
+        put_bits(&pb, 13, P_STD_max_video / 1024);
+
+        /* audio */
+        if (P_STD_max_mpeg_audio == 0)
+            P_STD_max_mpeg_audio = 4096;
+        put_bits(&pb, 8, 0xb8); /* stream ID */
+        put_bits(&pb, 2, 3);
+        put_bits(&pb, 1, 0);
+        put_bits(&pb, 13, P_STD_max_mpeg_audio / 128);
+
+        /* private stream 1 */
+        put_bits(&pb, 8, 0xbd); /* stream ID */
+        put_bits(&pb, 2, 3);
+        put_bits(&pb, 1, 0);
+        put_bits(&pb, 13, P_STD_max_mpeg_PS1 / 128);
+
+        /* private stream 2 */
+        put_bits(&pb, 8, 0xbf); /* stream ID */
+        put_bits(&pb, 2, 3);
+        put_bits(&pb, 1, 1);
+        put_bits(&pb, 13, 2);
+    }
+    else {
+        /* audio stream info */
+        private_stream_coded = 0;
+        for(i=0;i<ctx->nb_streams;i++) {
+            StreamInfo *stream = ctx->streams[i]->priv_data;
+
+
+            /* For VCDs, only include the stream info for the stream
+            that the pack which contains this system belongs to.
+            (see VCD standard p. IV-7) */
+            if ( !s->is_vcd || stream->id==only_for_stream_id
+                || only_for_stream_id==0) {
+
+                id = stream->id;
+                if (id < 0xc0) {
+                    /* special case for private streams (AC3 use that) */
+                    if (private_stream_coded)
+                        continue;
+                    private_stream_coded = 1;
+                    id = 0xbd;
+                }
+                put_bits(&pb, 8, id); /* stream ID */
+                put_bits(&pb, 2, 3);
+                if (id < 0xe0) {
+                    /* audio */
+                    put_bits(&pb, 1, 0);
+                    put_bits(&pb, 13, stream->max_buffer_size / 128);
+                } else {
+                    /* video */
+                    put_bits(&pb, 1, 1);
+                    put_bits(&pb, 13, stream->max_buffer_size / 1024);
+                }
+            }
+        }
+    }
+
+    flush_put_bits(&pb);
+    size = pbBufPtr(&pb) - pb.buf;
+    /* patch packet size */
+    buf[4] = (size - 6) >> 8;
+    buf[5] = (size - 6) & 0xff;
+
+    return size;
+}
+
+static int get_system_header_size(AVFormatContext *ctx)
+{
+    int buf_index, i, private_stream_coded;
+    StreamInfo *stream;
+    MpegMuxContext *s = ctx->priv_data;
+
+    if (s->is_dvd)
+       return 18; // DVD-Video system headers are 18 bytes fixed length.
+
+    buf_index = 12;
+    private_stream_coded = 0;
+    for(i=0;i<ctx->nb_streams;i++) {
+        stream = ctx->streams[i]->priv_data;
+        if (stream->id < 0xc0) {
+            if (private_stream_coded)
+                continue;
+            private_stream_coded = 1;
+        }
+        buf_index += 3;
+    }
+    return buf_index;
+}
+
+static int mpeg_mux_init(AVFormatContext *ctx)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    int bitrate, i, mpa_id, mpv_id, mps_id, ac3_id, dts_id, lpcm_id, j;
+    AVStream *st;
+    StreamInfo *stream;
+    int audio_bitrate;
+    int video_bitrate;
+
+    s->packet_number = 0;
+    s->is_vcd = (ctx->oformat == &mpeg1vcd_muxer);
+    s->is_svcd = (ctx->oformat == &mpeg2svcd_muxer);
+    s->is_mpeg2 = (ctx->oformat == &mpeg2vob_muxer || ctx->oformat == &mpeg2svcd_muxer || ctx->oformat == &mpeg2dvd_muxer);
+    s->is_dvd = (ctx->oformat == &mpeg2dvd_muxer);
+
+    if(ctx->packet_size)
+        s->packet_size = ctx->packet_size;
+    else
+        s->packet_size = 2048;
+
+    s->vcd_padding_bytes_written = 0;
+    s->vcd_padding_bitrate=0;
+
+    s->audio_bound = 0;
+    s->video_bound = 0;
+    mpa_id = AUDIO_ID;
+    ac3_id = AC3_ID;
+    dts_id = DTS_ID;
+    mpv_id = VIDEO_ID;
+    mps_id = SUB_ID;
+    lpcm_id = LPCM_ID;
+    for(i=0;i<ctx->nb_streams;i++) {
+        st = ctx->streams[i];
+        stream = av_mallocz(sizeof(StreamInfo));
+        if (!stream)
+            goto fail;
+        st->priv_data = stream;
+
+        av_set_pts_info(st, 64, 1, 90000);
+
+        switch(st->codec->codec_type) {
+        case CODEC_TYPE_AUDIO:
+            if (st->codec->codec_id == CODEC_ID_AC3) {
+                stream->id = ac3_id++;
+            } else if (st->codec->codec_id == CODEC_ID_DTS) {
+                stream->id = dts_id++;
+            } else if (st->codec->codec_id == CODEC_ID_PCM_S16BE) {
+                stream->id = lpcm_id++;
+                for(j = 0; j < 4; j++) {
+                    if (lpcm_freq_tab[j] == st->codec->sample_rate)
+                        break;
+                }
+                if (j == 4)
+                    goto fail;
+                if (st->codec->channels > 8)
+                    return -1;
+                stream->lpcm_header[0] = 0x0c;
+                stream->lpcm_header[1] = (st->codec->channels - 1) | (j << 4);
+                stream->lpcm_header[2] = 0x80;
+                stream->lpcm_align = st->codec->channels * 2;
+            } else {
+                stream->id = mpa_id++;
+            }
+
+            /* This value HAS to be used for VCD (see VCD standard, p. IV-7).
+               Right now it is also used for everything else.*/
+            stream->max_buffer_size = 4 * 1024;
+            s->audio_bound++;
+            break;
+        case CODEC_TYPE_VIDEO:
+            stream->id = mpv_id++;
+            if (st->codec->rc_buffer_size)
+                stream->max_buffer_size = 6*1024 + st->codec->rc_buffer_size/8;
+            else
+                stream->max_buffer_size = 230*1024; //FIXME this is probably too small as default
+#if 0
+                /* see VCD standard, p. IV-7*/
+                stream->max_buffer_size = 46 * 1024;
+            else
+                /* This value HAS to be used for SVCD (see SVCD standard, p. 26 V.2.3.2).
+                   Right now it is also used for everything else.*/
+                stream->max_buffer_size = 230 * 1024;
+#endif
+            s->video_bound++;
+            break;
+        case CODEC_TYPE_SUBTITLE:
+            stream->id = mps_id++;
+            stream->max_buffer_size = 16 * 1024;
+            break;
+        default:
+            return -1;
+        }
+        av_fifo_init(&stream->fifo, 16);
+    }
+    bitrate = 0;
+    audio_bitrate = 0;
+    video_bitrate = 0;
+    for(i=0;i<ctx->nb_streams;i++) {
+        int codec_rate;
+        st = ctx->streams[i];
+        stream = (StreamInfo*) st->priv_data;
+
+        if(st->codec->rc_max_rate || stream->id==VIDEO_ID)
+            codec_rate= st->codec->rc_max_rate;
+        else
+            codec_rate= st->codec->bit_rate;
+
+        if(!codec_rate)
+            codec_rate= (1<<21)*8*50/ctx->nb_streams;
+
+        bitrate += codec_rate;
+
+        if (stream->id==AUDIO_ID)
+            audio_bitrate += codec_rate;
+        else if (stream->id==VIDEO_ID)
+            video_bitrate += codec_rate;
+    }
+
+    if(ctx->mux_rate){
+        s->mux_rate= (ctx->mux_rate + (8 * 50) - 1) / (8 * 50);
+    } else {
+        /* we increase slightly the bitrate to take into account the
+           headers. XXX: compute it exactly */
+        bitrate += bitrate*5/100;
+        bitrate += 10000;
+        s->mux_rate = (bitrate + (8 * 50) - 1) / (8 * 50);
+    }
+
+    if (s->is_vcd) {
+        double overhead_rate;
+
+        /* The VCD standard mandates that the mux_rate field is 3528
+           (see standard p. IV-6).
+           The value is actually "wrong", i.e. if you calculate
+           it using the normal formula and the 75 sectors per second transfer
+           rate you get a different value because the real pack size is 2324,
+           not 2352. But the standard explicitly specifies that the mux_rate
+           field in the header must have this value.*/
+//        s->mux_rate=2352 * 75 / 50;    /* = 3528*/
+
+        /* The VCD standard states that the muxed stream must be
+           exactly 75 packs / second (the data rate of a single speed cdrom).
+           Since the video bitrate (probably 1150000 bits/sec) will be below
+           the theoretical maximum we have to add some padding packets
+           to make up for the lower data rate.
+           (cf. VCD standard p. IV-6 )*/
+
+        /* Add the header overhead to the data rate.
+           2279 data bytes per audio pack, 2294 data bytes per video pack*/
+        overhead_rate = ((audio_bitrate / 8.0) / 2279) * (2324 - 2279);
+        overhead_rate += ((video_bitrate / 8.0) / 2294) * (2324 - 2294);
+        overhead_rate *= 8;
+
+        /* Add padding so that the full bitrate is 2324*75 bytes/sec */
+        s->vcd_padding_bitrate = 2324 * 75 * 8 - (bitrate + overhead_rate);
+    }
+
+    if (s->is_vcd || s->is_mpeg2)
+        /* every packet */
+        s->pack_header_freq = 1;
+    else
+        /* every 2 seconds */
+        s->pack_header_freq = 2 * bitrate / s->packet_size / 8;
+
+    /* the above seems to make pack_header_freq zero sometimes */
+    if (s->pack_header_freq == 0)
+       s->pack_header_freq = 1;
+
+    if (s->is_mpeg2)
+        /* every 200 packets. Need to look at the spec.  */
+        s->system_header_freq = s->pack_header_freq * 40;
+    else if (s->is_vcd)
+        /* the standard mandates that there are only two system headers
+           in the whole file: one in the first packet of each stream.
+           (see standard p. IV-7 and IV-8) */
+        s->system_header_freq = 0x7fffffff;
+    else
+        s->system_header_freq = s->pack_header_freq * 5;
+
+    for(i=0;i<ctx->nb_streams;i++) {
+        stream = ctx->streams[i]->priv_data;
+        stream->packet_number = 0;
+    }
+    s->system_header_size = get_system_header_size(ctx);
+    s->last_scr = 0;
+    return 0;
+ fail:
+    for(i=0;i<ctx->nb_streams;i++) {
+        av_free(ctx->streams[i]->priv_data);
+    }
+    return AVERROR(ENOMEM);
+}
+
+static inline void put_timestamp(ByteIOContext *pb, int id, int64_t timestamp)
+{
+    put_byte(pb,
+             (id << 4) |
+             (((timestamp >> 30) & 0x07) << 1) |
+             1);
+    put_be16(pb, (uint16_t)((((timestamp >> 15) & 0x7fff) << 1) | 1));
+    put_be16(pb, (uint16_t)((((timestamp) & 0x7fff) << 1) | 1));
+}
+
+
+/* return the number of padding bytes that should be inserted into
+   the multiplexed stream.*/
+static int get_vcd_padding_size(AVFormatContext *ctx, int64_t pts)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    int pad_bytes = 0;
+
+    if (s->vcd_padding_bitrate > 0 && pts!=AV_NOPTS_VALUE)
+    {
+        int64_t full_pad_bytes;
+
+        full_pad_bytes = (int64_t)((s->vcd_padding_bitrate * (pts / 90000.0)) / 8.0); //FIXME this is wrong
+        pad_bytes = (int) (full_pad_bytes - s->vcd_padding_bytes_written);
+
+        if (pad_bytes<0)
+            /* might happen if we have already padded to a later timestamp. This
+               can occur if another stream has already advanced further.*/
+            pad_bytes=0;
+    }
+
+    return pad_bytes;
+}
+
+
+#if 0 /* unused, remove? */
+/* return the exact available payload size for the next packet for
+   stream 'stream_index'. 'pts' and 'dts' are only used to know if
+   timestamps are needed in the packet header. */
+static int get_packet_payload_size(AVFormatContext *ctx, int stream_index,
+                                   int64_t pts, int64_t dts)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    int buf_index;
+    StreamInfo *stream;
+
+    stream = ctx->streams[stream_index]->priv_data;
+
+    buf_index = 0;
+    if (((s->packet_number % s->pack_header_freq) == 0)) {
+        /* pack header size */
+        if (s->is_mpeg2)
+            buf_index += 14;
+        else
+            buf_index += 12;
+
+        if (s->is_vcd) {
+            /* there is exactly one system header for each stream in a VCD MPEG,
+               One in the very first video packet and one in the very first
+               audio packet (see VCD standard p. IV-7 and IV-8).*/
+
+            if (stream->packet_number==0)
+                /* The system headers refer only to the stream they occur in,
+                   so they have a constant size.*/
+                buf_index += 15;
+
+        } else {
+            if ((s->packet_number % s->system_header_freq) == 0)
+                buf_index += s->system_header_size;
+        }
+    }
+
+    if ((s->is_vcd && stream->packet_number==0)
+        || (s->is_svcd && s->packet_number==0))
+        /* the first pack of each stream contains only the pack header,
+           the system header and some padding (see VCD standard p. IV-6)
+           Add the padding size, so that the actual payload becomes 0.*/
+        buf_index += s->packet_size - buf_index;
+    else {
+        /* packet header size */
+        buf_index += 6;
+        if (s->is_mpeg2) {
+            buf_index += 3;
+            if (stream->packet_number==0)
+                buf_index += 3; /* PES extension */
+            buf_index += 1;    /* obligatory stuffing byte */
+        }
+        if (pts != AV_NOPTS_VALUE) {
+            if (dts != pts)
+                buf_index += 5 + 5;
+            else
+                buf_index += 5;
+
+        } else {
+            if (!s->is_mpeg2)
+                buf_index++;
+        }
+
+        if (stream->id < 0xc0) {
+            /* AC3/LPCM private data header */
+            buf_index += 4;
+            if (stream->id >= 0xa0) {
+                int n;
+                buf_index += 3;
+                /* NOTE: we round the payload size to an integer number of
+                   LPCM samples */
+                n = (s->packet_size - buf_index) % stream->lpcm_align;
+                if (n)
+                    buf_index += (stream->lpcm_align - n);
+            }
+        }
+
+        if (s->is_vcd && stream->id == AUDIO_ID)
+            /* The VCD standard demands that 20 zero bytes follow
+               each audio packet (see standard p. IV-8).*/
+            buf_index+=20;
+    }
+    return s->packet_size - buf_index;
+}
+#endif
+
+/* Write an MPEG padding packet header. */
+static void put_padding_packet(AVFormatContext *ctx, ByteIOContext *pb,int packet_bytes)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    int i;
+
+    put_be32(pb, PADDING_STREAM);
+    put_be16(pb, packet_bytes - 6);
+    if (!s->is_mpeg2) {
+        put_byte(pb, 0x0f);
+        packet_bytes -= 7;
+    } else
+        packet_bytes -= 6;
+
+    for(i=0;i<packet_bytes;i++)
+        put_byte(pb, 0xff);
+}
+
+static int get_nb_frames(AVFormatContext *ctx, StreamInfo *stream, int len){
+    int nb_frames=0;
+    PacketDesc *pkt_desc= stream->premux_packet;
+
+    while(len>0){
+        if(pkt_desc->size == pkt_desc->unwritten_size)
+            nb_frames++;
+        len -= pkt_desc->unwritten_size;
+        pkt_desc= pkt_desc->next;
+    }
+
+    return nb_frames;
+}
+
+/* flush the packet on stream stream_index */
+static int flush_packet(AVFormatContext *ctx, int stream_index,
+                         int64_t pts, int64_t dts, int64_t scr, int trailer_size)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    StreamInfo *stream = ctx->streams[stream_index]->priv_data;
+    uint8_t *buf_ptr;
+    int size, payload_size, startcode, id, stuffing_size, i, header_len;
+    int packet_size;
+    uint8_t buffer[128];
+    int zero_trail_bytes = 0;
+    int pad_packet_bytes = 0;
+    int pes_flags;
+    int general_pack = 0;  /*"general" pack without data specific to one stream?*/
+    int nb_frames;
+
+    id = stream->id;
+
+#if 0
+    printf("packet ID=%2x PTS=%0.3f\n",
+           id, pts / 90000.0);
+#endif
+
+    buf_ptr = buffer;
+
+    if ((s->packet_number % s->pack_header_freq) == 0 || s->last_scr != scr) {
+        /* output pack and systems header if needed */
+        size = put_pack_header(ctx, buf_ptr, scr);
+        buf_ptr += size;
+        s->last_scr= scr;
+
+        if (s->is_vcd) {
+            /* there is exactly one system header for each stream in a VCD MPEG,
+               One in the very first video packet and one in the very first
+               audio packet (see VCD standard p. IV-7 and IV-8).*/
+
+            if (stream->packet_number==0) {
+                size = put_system_header(ctx, buf_ptr, id);
+                buf_ptr += size;
+            }
+        } else if (s->is_dvd) {
+            if (stream->align_iframe || s->packet_number == 0){
+                int PES_bytes_to_fill = s->packet_size - size - 10;
+
+                if (pts != AV_NOPTS_VALUE) {
+                    if (dts != pts)
+                        PES_bytes_to_fill -= 5 + 5;
+                    else
+                        PES_bytes_to_fill -= 5;
+                }
+
+                if (stream->bytes_to_iframe == 0 || s->packet_number == 0) {
+                    size = put_system_header(ctx, buf_ptr, 0);
+                    buf_ptr += size;
+                    size = buf_ptr - buffer;
+                    put_buffer(&ctx->pb, buffer, size);
+
+                    put_be32(&ctx->pb, PRIVATE_STREAM_2);
+                    put_be16(&ctx->pb, 0x03d4);         // length
+                    put_byte(&ctx->pb, 0x00);           // substream ID, 00=PCI
+                    for (i = 0; i < 979; i++)
+                        put_byte(&ctx->pb, 0x00);
+
+                    put_be32(&ctx->pb, PRIVATE_STREAM_2);
+                    put_be16(&ctx->pb, 0x03fa);         // length
+                    put_byte(&ctx->pb, 0x01);           // substream ID, 01=DSI
+                    for (i = 0; i < 1017; i++)
+                        put_byte(&ctx->pb, 0x00);
+
+                    memset(buffer, 0, 128);
+                    buf_ptr = buffer;
+                    s->packet_number++;
+                    stream->align_iframe = 0;
+                    scr += s->packet_size*90000LL / (s->mux_rate*50LL); //FIXME rounding and first few bytes of each packet
+                    size = put_pack_header(ctx, buf_ptr, scr);
+                    s->last_scr= scr;
+                    buf_ptr += size;
+                    /* GOP Start */
+                } else if (stream->bytes_to_iframe < PES_bytes_to_fill) {
+                    pad_packet_bytes = PES_bytes_to_fill - stream->bytes_to_iframe;
+                }
+            }
+        } else {
+            if ((s->packet_number % s->system_header_freq) == 0) {
+                size = put_system_header(ctx, buf_ptr, 0);
+                buf_ptr += size;
+            }
+        }
+    }
+    size = buf_ptr - buffer;
+    put_buffer(&ctx->pb, buffer, size);
+
+    packet_size = s->packet_size - size;
+
+    if (s->is_vcd && id == AUDIO_ID)
+        /* The VCD standard demands that 20 zero bytes follow
+           each audio pack (see standard p. IV-8).*/
+        zero_trail_bytes += 20;
+
+    if ((s->is_vcd && stream->packet_number==0)
+        || (s->is_svcd && s->packet_number==0)) {
+        /* for VCD the first pack of each stream contains only the pack header,
+           the system header and lots of padding (see VCD standard p. IV-6).
+           In the case of an audio pack, 20 zero bytes are also added at
+           the end.*/
+        /* For SVCD we fill the very first pack to increase compatibility with
+           some DVD players. Not mandated by the standard.*/
+        if (s->is_svcd)
+            general_pack = 1;    /* the system header refers to both streams and no stream data*/
+        pad_packet_bytes = packet_size - zero_trail_bytes;
+    }
+
+    packet_size -= pad_packet_bytes + zero_trail_bytes;
+
+    if (packet_size > 0) {
+
+        /* packet header size */
+        packet_size -= 6;
+
+        /* packet header */
+        if (s->is_mpeg2) {
+            header_len = 3;
+            if (stream->packet_number==0)
+                header_len += 3; /* PES extension */
+            header_len += 1; /* obligatory stuffing byte */
+        } else {
+            header_len = 0;
+        }
+        if (pts != AV_NOPTS_VALUE) {
+            if (dts != pts)
+                header_len += 5 + 5;
+            else
+                header_len += 5;
+        } else {
+            if (!s->is_mpeg2)
+                header_len++;
+        }
+
+        payload_size = packet_size - header_len;
+        if (id < 0xc0) {
+            startcode = PRIVATE_STREAM_1;
+            payload_size -= 1;
+            if (id >= 0x40) {
+                payload_size -= 3;
+                if (id >= 0xa0)
+                    payload_size -= 3;
+            }
+        } else {
+            startcode = 0x100 + id;
+        }
+
+        stuffing_size = payload_size - av_fifo_size(&stream->fifo);
+
+        // first byte does not fit -> reset pts/dts + stuffing
+        if(payload_size <= trailer_size && pts != AV_NOPTS_VALUE){
+            int timestamp_len=0;
+            if(dts != pts)
+                timestamp_len += 5;
+            if(pts != AV_NOPTS_VALUE)
+                timestamp_len += s->is_mpeg2 ? 5 : 4;
+            pts=dts= AV_NOPTS_VALUE;
+            header_len -= timestamp_len;
+            if (s->is_dvd && stream->align_iframe) {
+                pad_packet_bytes += timestamp_len;
+                packet_size -= timestamp_len;
+            } else {
+                payload_size += timestamp_len;
+            }
+            stuffing_size += timestamp_len;
+            if(payload_size > trailer_size)
+                stuffing_size += payload_size - trailer_size;
+        }
+
+        if (pad_packet_bytes > 0 && pad_packet_bytes <= 7) { // can't use padding, so use stuffing
+            packet_size += pad_packet_bytes;
+            payload_size += pad_packet_bytes; // undo the previous adjustment
+            if (stuffing_size < 0) {
+                stuffing_size = pad_packet_bytes;
+            } else {
+                stuffing_size += pad_packet_bytes;
+            }
+            pad_packet_bytes = 0;
+        }
+
+        if (stuffing_size < 0)
+            stuffing_size = 0;
+        if (stuffing_size > 16) {    /*<=16 for MPEG-1, <=32 for MPEG-2*/
+            pad_packet_bytes += stuffing_size;
+            packet_size -= stuffing_size;
+            payload_size -= stuffing_size;
+            stuffing_size = 0;
+        }
+
+        nb_frames= get_nb_frames(ctx, stream, payload_size - stuffing_size);
+
+        put_be32(&ctx->pb, startcode);
+
+        put_be16(&ctx->pb, packet_size);
+
+        if (!s->is_mpeg2)
+            for(i=0;i<stuffing_size;i++)
+                put_byte(&ctx->pb, 0xff);
+
+        if (s->is_mpeg2) {
+            put_byte(&ctx->pb, 0x80); /* mpeg2 id */
+
+            pes_flags=0;
+
+            if (pts != AV_NOPTS_VALUE) {
+                pes_flags |= 0x80;
+                if (dts != pts)
+                    pes_flags |= 0x40;
+            }
+
+            /* Both the MPEG-2 and the SVCD standards demand that the
+               P-STD_buffer_size field be included in the first packet of
+               every stream. (see SVCD standard p. 26 V.2.3.1 and V.2.3.2
+               and MPEG-2 standard 2.7.7) */
+            if (stream->packet_number == 0)
+                pes_flags |= 0x01;
+
+            put_byte(&ctx->pb, pes_flags); /* flags */
+            put_byte(&ctx->pb, header_len - 3 + stuffing_size);
+
+            if (pes_flags & 0x80)  /*write pts*/
+                put_timestamp(&ctx->pb, (pes_flags & 0x40) ? 0x03 : 0x02, pts);
+            if (pes_flags & 0x40)  /*write dts*/
+                put_timestamp(&ctx->pb, 0x01, dts);
+
+            if (pes_flags & 0x01) {  /*write pes extension*/
+                put_byte(&ctx->pb, 0x10); /* flags */
+
+                /* P-STD buffer info */
+                if (id == AUDIO_ID)
+                    put_be16(&ctx->pb, 0x4000 | stream->max_buffer_size/128);
+                else
+                    put_be16(&ctx->pb, 0x6000 | stream->max_buffer_size/1024);
+            }
+
+        } else {
+            if (pts != AV_NOPTS_VALUE) {
+                if (dts != pts) {
+                    put_timestamp(&ctx->pb, 0x03, pts);
+                    put_timestamp(&ctx->pb, 0x01, dts);
+                } else {
+                    put_timestamp(&ctx->pb, 0x02, pts);
+                }
+            } else {
+                put_byte(&ctx->pb, 0x0f);
+            }
+        }
+
+        if (s->is_mpeg2) {
+            /* special stuffing byte that is always written
+               to prevent accidental generation of start codes. */
+            put_byte(&ctx->pb, 0xff);
+
+            for(i=0;i<stuffing_size;i++)
+                put_byte(&ctx->pb, 0xff);
+        }
+
+        if (startcode == PRIVATE_STREAM_1) {
+            put_byte(&ctx->pb, id);
+            if (id >= 0xa0) {
+                /* LPCM (XXX: check nb_frames) */
+                put_byte(&ctx->pb, 7);
+                put_be16(&ctx->pb, 4); /* skip 3 header bytes */
+                put_byte(&ctx->pb, stream->lpcm_header[0]);
+                put_byte(&ctx->pb, stream->lpcm_header[1]);
+                put_byte(&ctx->pb, stream->lpcm_header[2]);
+            } else if (id >= 0x40) {
+                /* AC3 */
+                put_byte(&ctx->pb, nb_frames);
+                put_be16(&ctx->pb, trailer_size+1);
+            }
+        }
+
+        /* output data */
+        if(av_fifo_generic_read(&stream->fifo, payload_size - stuffing_size, &put_buffer, &ctx->pb) < 0)
+            return -1;
+        stream->bytes_to_iframe -= payload_size - stuffing_size;
+    }else{
+        payload_size=
+        stuffing_size= 0;
+    }
+
+    if (pad_packet_bytes > 0)
+        put_padding_packet(ctx,&ctx->pb, pad_packet_bytes);
+
+    for(i=0;i<zero_trail_bytes;i++)
+        put_byte(&ctx->pb, 0x00);
+
+    put_flush_packet(&ctx->pb);
+
+    s->packet_number++;
+
+    /* only increase the stream packet number if this pack actually contains
+       something that is specific to this stream! I.e. a dedicated header
+       or some data.*/
+    if (!general_pack)
+        stream->packet_number++;
+
+    return payload_size - stuffing_size;
+}
+
+static void put_vcd_padding_sector(AVFormatContext *ctx)
+{
+    /* There are two ways to do this padding: writing a sector/pack
+       of 0 values, or writing an MPEG padding pack. Both seem to
+       work with most decoders, BUT the VCD standard only allows a 0-sector
+       (see standard p. IV-4, IV-5).
+       So a 0-sector it is...*/
+
+    MpegMuxContext *s = ctx->priv_data;
+    int i;
+
+    for(i=0;i<s->packet_size;i++)
+        put_byte(&ctx->pb, 0);
+
+    s->vcd_padding_bytes_written += s->packet_size;
+
+    put_flush_packet(&ctx->pb);
+
+    /* increasing the packet number is correct. The SCR of the following packs
+       is calculated from the packet_number and it has to include the padding
+       sector (it represents the sector index, not the MPEG pack index)
+       (see VCD standard p. IV-6)*/
+    s->packet_number++;
+}
+
+#if 0 /* unused, remove? */
+static int64_t get_vcd_scr(AVFormatContext *ctx,int stream_index,int64_t pts)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    int64_t scr;
+
+        /* Since the data delivery rate is constant, SCR is computed
+           using the formula C + i * 1200 where C is the start constant
+           and i is the pack index.
+           It is recommended that SCR 0 is at the beginning of the VCD front
+           margin (a sequence of empty Form 2 sectors on the CD).
+           It is recommended that the front margin is 30 sectors long, so
+           we use C = 30*1200 = 36000
+           (Note that even if the front margin is not 30 sectors the file
+           will still be correct according to the standard. It just won't have
+           the "recommended" value).*/
+        scr = 36000 + s->packet_number * 1200;
+
+    return scr;
+}
+#endif
+
+static int remove_decoded_packets(AVFormatContext *ctx, int64_t scr){
+//    MpegMuxContext *s = ctx->priv_data;
+    int i;
+
+    for(i=0; i<ctx->nb_streams; i++){
+        AVStream *st = ctx->streams[i];
+        StreamInfo *stream = st->priv_data;
+        PacketDesc *pkt_desc;
+
+        while((pkt_desc= stream->predecode_packet)
+              && scr > pkt_desc->dts){ //FIXME > vs >=
+            if(stream->buffer_index < pkt_desc->size ||
+               stream->predecode_packet == stream->premux_packet){
+                av_log(ctx, AV_LOG_ERROR,
+                       "buffer underflow i=%d bufi=%d size=%d\n",
+                       i, stream->buffer_index, pkt_desc->size);
+                break;
+            }
+            stream->buffer_index -= pkt_desc->size;
+
+            stream->predecode_packet= pkt_desc->next;
+            av_freep(&pkt_desc);
+        }
+    }
+
+    return 0;
+}
+
+static int output_packet(AVFormatContext *ctx, int flush){
+    MpegMuxContext *s = ctx->priv_data;
+    AVStream *st;
+    StreamInfo *stream;
+    int i, avail_space, es_size, trailer_size;
+    int best_i= -1;
+    int best_score= INT_MIN;
+    int ignore_constraints=0;
+    int64_t scr= s->last_scr;
+    PacketDesc *timestamp_packet;
+    const int64_t max_delay= av_rescale(ctx->max_delay, 90000, AV_TIME_BASE);
+
+retry:
+    for(i=0; i<ctx->nb_streams; i++){
+        AVStream *st = ctx->streams[i];
+        StreamInfo *stream = st->priv_data;
+        const int avail_data=  av_fifo_size(&stream->fifo);
+        const int space= stream->max_buffer_size - stream->buffer_index;
+        int rel_space= 1024*space / stream->max_buffer_size;
+        PacketDesc *next_pkt= stream->premux_packet;
+
+        /* for subtitle, a single PES packet must be generated,
+           so we flush after every single subtitle packet */
+        if(s->packet_size > avail_data && !flush
+           && st->codec->codec_type != CODEC_TYPE_SUBTITLE)
+            return 0;
+        if(avail_data==0)
+            continue;
+        assert(avail_data>0);
+
+        if(space < s->packet_size && !ignore_constraints)
+            continue;
+
+        if(next_pkt && next_pkt->dts - scr > max_delay)
+            continue;
+
+        if(rel_space > best_score){
+            best_score= rel_space;
+            best_i = i;
+            avail_space= space;
+        }
+    }
+
+    if(best_i < 0){
+        int64_t best_dts= INT64_MAX;
+
+        for(i=0; i<ctx->nb_streams; i++){
+            AVStream *st = ctx->streams[i];
+            StreamInfo *stream = st->priv_data;
+            PacketDesc *pkt_desc= stream->predecode_packet;
+            if(pkt_desc && pkt_desc->dts < best_dts)
+                best_dts= pkt_desc->dts;
+        }
+
+#if 0
+        av_log(ctx, AV_LOG_DEBUG, "bumping scr, scr:%f, dts:%f\n",
+               scr/90000.0, best_dts/90000.0);
+#endif
+        if(best_dts == INT64_MAX)
+            return 0;
+
+        if(scr >= best_dts+1 && !ignore_constraints){
+            av_log(ctx, AV_LOG_ERROR, "packet too large, ignoring buffer limits to mux it\n");
+            ignore_constraints= 1;
+        }
+        scr= FFMAX(best_dts+1, scr);
+        if(remove_decoded_packets(ctx, scr) < 0)
+            return -1;
+        goto retry;
+    }
+
+    assert(best_i >= 0);
+
+    st = ctx->streams[best_i];
+    stream = st->priv_data;
+
+    assert(av_fifo_size(&stream->fifo) > 0);
+
+    assert(avail_space >= s->packet_size || ignore_constraints);
+
+    timestamp_packet= stream->premux_packet;
+    if(timestamp_packet->unwritten_size == timestamp_packet->size){
+        trailer_size= 0;
+    }else{
+        trailer_size= timestamp_packet->unwritten_size;
+        timestamp_packet= timestamp_packet->next;
+    }
+
+    if(timestamp_packet){
+//av_log(ctx, AV_LOG_DEBUG, "dts:%f pts:%f scr:%f stream:%d\n", timestamp_packet->dts/90000.0, timestamp_packet->pts/90000.0, scr/90000.0, best_i);
+        es_size= flush_packet(ctx, best_i, timestamp_packet->pts, timestamp_packet->dts, scr, trailer_size);
+    }else{
+        assert(av_fifo_size(&stream->fifo) == trailer_size);
+        es_size= flush_packet(ctx, best_i, AV_NOPTS_VALUE, AV_NOPTS_VALUE, scr, trailer_size);
+    }
+
+    if (s->is_vcd) {
+        /* Write one or more padding sectors, if necessary, to reach
+           the constant overall bitrate.*/
+        int vcd_pad_bytes;
+
+        while((vcd_pad_bytes = get_vcd_padding_size(ctx,stream->premux_packet->pts) ) >= s->packet_size){ //FIXME pts cannot be correct here
+            put_vcd_padding_sector(ctx);
+            s->last_scr += s->packet_size*90000LL / (s->mux_rate*50LL); //FIXME rounding and first few bytes of each packet
+        }
+    }
+
+    stream->buffer_index += es_size;
+    s->last_scr += s->packet_size*90000LL / (s->mux_rate*50LL); //FIXME rounding and first few bytes of each packet
+
+    while(stream->premux_packet && stream->premux_packet->unwritten_size <= es_size){
+        es_size -= stream->premux_packet->unwritten_size;
+        stream->premux_packet= stream->premux_packet->next;
+    }
+    if(es_size)
+        stream->premux_packet->unwritten_size -= es_size;
+
+    if(remove_decoded_packets(ctx, s->last_scr) < 0)
+        return -1;
+
+    return 1;
+}
+
+static int mpeg_mux_write_packet(AVFormatContext *ctx, AVPacket *pkt)
+{
+    MpegMuxContext *s = ctx->priv_data;
+    int stream_index= pkt->stream_index;
+    int size= pkt->size;
+    uint8_t *buf= pkt->data;
+    AVStream *st = ctx->streams[stream_index];
+    StreamInfo *stream = st->priv_data;
+    int64_t pts, dts;
+    PacketDesc *pkt_desc;
+    const int preload= av_rescale(ctx->preload, 90000, AV_TIME_BASE);
+    const int is_iframe = st->codec->codec_type == CODEC_TYPE_VIDEO && (pkt->flags & PKT_FLAG_KEY);
+
+    pts= pkt->pts;
+    dts= pkt->dts;
+
+    if(pts != AV_NOPTS_VALUE) pts += preload;
+    if(dts != AV_NOPTS_VALUE) dts += preload;
+
+//av_log(ctx, AV_LOG_DEBUG, "dts:%f pts:%f flags:%d stream:%d nopts:%d\n", dts/90000.0, pts/90000.0, pkt->flags, pkt->stream_index, pts != AV_NOPTS_VALUE);
+    if (!stream->premux_packet)
+        stream->next_packet = &stream->premux_packet;
+    *stream->next_packet=
+    pkt_desc= av_mallocz(sizeof(PacketDesc));
+    pkt_desc->pts= pts;
+    pkt_desc->dts= dts;
+    pkt_desc->unwritten_size=
+    pkt_desc->size= size;
+    if(!stream->predecode_packet)
+        stream->predecode_packet= pkt_desc;
+    stream->next_packet= &pkt_desc->next;
+
+    av_fifo_realloc(&stream->fifo, av_fifo_size(&stream->fifo) + size + 1);
+
+    if (s->is_dvd){
+        if (is_iframe && (s->packet_number == 0 || (pts - stream->vobu_start_pts >= 36000))) { // min VOBU length 0.4 seconds (mpucoder)
+            stream->bytes_to_iframe = av_fifo_size(&stream->fifo);
+            stream->align_iframe = 1;
+            stream->vobu_start_pts = pts;
+        } else {
+            stream->align_iframe = 0;
+        }
+    }
+
+    av_fifo_write(&stream->fifo, buf, size);
+
+    for(;;){
+        int ret= output_packet(ctx, 0);
+        if(ret<=0)
+            return ret;
+    }
+}
+
+static int mpeg_mux_end(AVFormatContext *ctx)
+{
+//    MpegMuxContext *s = ctx->priv_data;
+    StreamInfo *stream;
+    int i;
+
+    for(;;){
+        int ret= output_packet(ctx, 1);
+        if(ret<0)
+            return ret;
+        else if(ret==0)
+            break;
+    }
+
+    /* End header according to MPEG1 systems standard. We do not write
+       it as it is usually not needed by decoders and because it
+       complicates MPEG stream concatenation. */
+    //put_be32(&ctx->pb, ISO_11172_END_CODE);
+    //put_flush_packet(&ctx->pb);
+
+    for(i=0;i<ctx->nb_streams;i++) {
+        stream = ctx->streams[i]->priv_data;
+
+        assert(av_fifo_size(&stream->fifo) == 0);
+        av_fifo_free(&stream->fifo);
+    }
+    return 0;
+}
+#endif //CONFIG_MUXERS
+
+#ifdef CONFIG_MPEG1SYSTEM_MUXER
+AVOutputFormat mpeg1system_muxer = {
+    "mpeg",
+    "MPEG1 System format",
+    "video/mpeg",
+    "mpg,mpeg",
+    sizeof(MpegMuxContext),
+    CODEC_ID_MP2,
+    CODEC_ID_MPEG1VIDEO,
+    mpeg_mux_init,
+    mpeg_mux_write_packet,
+    mpeg_mux_end,
+};
+#endif
+#ifdef CONFIG_MPEG1VCD_MUXER
+AVOutputFormat mpeg1vcd_muxer = {
+    "vcd",
+    "MPEG1 System format (VCD)",
+    "video/mpeg",
+    NULL,
+    sizeof(MpegMuxContext),
+    CODEC_ID_MP2,
+    CODEC_ID_MPEG1VIDEO,
+    mpeg_mux_init,
+    mpeg_mux_write_packet,
+    mpeg_mux_end,
+};
+#endif
+#ifdef CONFIG_MPEG2VOB_MUXER
+AVOutputFormat mpeg2vob_muxer = {
+    "vob",
+    "MPEG2 PS format (VOB)",
+    "video/mpeg",
+    "vob",
+    sizeof(MpegMuxContext),
+    CODEC_ID_MP2,
+    CODEC_ID_MPEG2VIDEO,
+    mpeg_mux_init,
+    mpeg_mux_write_packet,
+    mpeg_mux_end,
+};
+#endif
+
+/* Same as mpeg2vob_mux except that the pack size is 2324 */
+#ifdef CONFIG_MPEG2SVCD_MUXER
+AVOutputFormat mpeg2svcd_muxer = {
+    "svcd",
+    "MPEG2 PS format (VOB)",
+    "video/mpeg",
+    "vob",
+    sizeof(MpegMuxContext),
+    CODEC_ID_MP2,
+    CODEC_ID_MPEG2VIDEO,
+    mpeg_mux_init,
+    mpeg_mux_write_packet,
+    mpeg_mux_end,
+};
+#endif
+
+/*  Same as mpeg2vob_mux except the 'is_dvd' flag is set to produce NAV pkts */
+#ifdef CONFIG_MPEG2DVD_MUXER
+AVOutputFormat mpeg2dvd_muxer = {
+    "dvd",
+    "MPEG2 PS format (DVD VOB)",
+    "video/mpeg",
+    "dvd",
+    sizeof(MpegMuxContext),
+    CODEC_ID_MP2,
+    CODEC_ID_MPEG2VIDEO,
+    mpeg_mux_init,
+    mpeg_mux_write_packet,
+    mpeg_mux_end,
+};
+#endif