libavformat/rtmppkt.c - third_party/ffmpeg - Git at Google

 /*
  * RTMP input format
  * Copyright (c) 2009 Kostya Shishkov
  *
  * 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 "libavcodec/bytestream.h"
 #include "libavutil/avstring.h"
 #include "libavutil/intfloat.h"
 #include "avformat.h"

 #include "rtmppkt.h"
 #include "flv.h"
 #include "url.h"

 void ff_amf_write_bool(uint8_t **dst, int val)
 {
     bytestream_put_byte(dst, AMF_DATA_TYPE_BOOL);
     bytestream_put_byte(dst, val);
 }

 void ff_amf_write_number(uint8_t **dst, double val)
 {
     bytestream_put_byte(dst, AMF_DATA_TYPE_NUMBER);
     bytestream_put_be64(dst, av_double2int(val));
 }

 void ff_amf_write_string(uint8_t **dst, const char *str)
 {
     bytestream_put_byte(dst, AMF_DATA_TYPE_STRING);
     bytestream_put_be16(dst, strlen(str));
     bytestream_put_buffer(dst, str, strlen(str));
 }

 void ff_amf_write_null(uint8_t **dst)
 {
     bytestream_put_byte(dst, AMF_DATA_TYPE_NULL);
 }

 void ff_amf_write_object_start(uint8_t **dst)
 {
     bytestream_put_byte(dst, AMF_DATA_TYPE_OBJECT);
 }

 void ff_amf_write_field_name(uint8_t **dst, const char *str)
 {
     bytestream_put_be16(dst, strlen(str));
     bytestream_put_buffer(dst, str, strlen(str));
 }

 void ff_amf_write_object_end(uint8_t **dst)
 {
     /* first two bytes are field name length = 0,
      * AMF object should end with it and end marker
      */
     bytestream_put_be24(dst, AMF_DATA_TYPE_OBJECT_END);
 }

 int ff_rtmp_packet_read(URLContext *h, RTMPPacket *p,
                         int chunk_size, RTMPPacket *prev_pkt)
 {
     uint8_t hdr, t, buf[16];
     int channel_id, timestamp, size, offset = 0;
     uint32_t extra = 0;
     enum RTMPPacketType type;
     int written = 0;

     if (ffurl_read(h, &hdr, 1) != 1)
         return AVERROR(EIO);
     written++;
     channel_id = hdr & 0x3F;

     if (channel_id < 2) { //special case for channel number >= 64
         buf[1] = 0;
         if (ffurl_read_complete(h, buf, channel_id + 1) != channel_id + 1)
             return AVERROR(EIO);
         written += channel_id + 1;
         channel_id = AV_RL16(buf) + 64;
     }
     size  = prev_pkt[channel_id].size;
     type  = prev_pkt[channel_id].type;
     extra = prev_pkt[channel_id].extra;

     hdr >>= 6;
     if (hdr == RTMP_PS_ONEBYTE) {
         timestamp = prev_pkt[channel_id].ts_delta;
     } else {
         if (ffurl_read_complete(h, buf, 3) != 3)
             return AVERROR(EIO);
         written += 3;
         timestamp = AV_RB24(buf);
         if (hdr != RTMP_PS_FOURBYTES) {
             if (ffurl_read_complete(h, buf, 3) != 3)
                 return AVERROR(EIO);
             written += 3;
             size = AV_RB24(buf);
             if (ffurl_read_complete(h, buf, 1) != 1)
                 return AVERROR(EIO);
             written++;
             type = buf[0];
             if (hdr == RTMP_PS_TWELVEBYTES) {
                 if (ffurl_read_complete(h, buf, 4) != 4)
                     return AVERROR(EIO);
                 written += 4;
                 extra = AV_RL32(buf);
             }
         }
         if (timestamp == 0xFFFFFF) {
             if (ffurl_read_complete(h, buf, 4) != 4)
                 return AVERROR(EIO);
             timestamp = AV_RB32(buf);
         }
     }
     if (hdr != RTMP_PS_TWELVEBYTES)
         timestamp += prev_pkt[channel_id].timestamp;

     if (ff_rtmp_packet_create(p, channel_id, type, timestamp, size))
         return -1;
     p->extra = extra;
     // save history
     prev_pkt[channel_id].channel_id = channel_id;
     prev_pkt[channel_id].type       = type;
     prev_pkt[channel_id].size       = size;
     prev_pkt[channel_id].ts_delta   = timestamp - prev_pkt[channel_id].timestamp;
     prev_pkt[channel_id].timestamp  = timestamp;
     prev_pkt[channel_id].extra      = extra;
     while (size > 0) {
         int toread = FFMIN(size, chunk_size);
         if (ffurl_read_complete(h, p->data + offset, toread) != toread) {
             ff_rtmp_packet_destroy(p);
             return AVERROR(EIO);
         }
         size    -= chunk_size;
         offset  += chunk_size;
         written += chunk_size;
         if (size > 0) {
             ffurl_read_complete(h, &t, 1); //marker
             written++;
             if (t != (0xC0 + channel_id))
                 return -1;
         }
     }
     return written;
 }

 int ff_rtmp_packet_write(URLContext *h, RTMPPacket *pkt,
                          int chunk_size, RTMPPacket *prev_pkt)
 {
     uint8_t pkt_hdr[16], *p = pkt_hdr;
     int mode = RTMP_PS_TWELVEBYTES;
     int off = 0;
     int written = 0;

     pkt->ts_delta = pkt->timestamp - prev_pkt[pkt->channel_id].timestamp;

     //if channel_id = 0, this is first presentation of prev_pkt, send full hdr.
     if (prev_pkt[pkt->channel_id].channel_id &&
         pkt->extra == prev_pkt[pkt->channel_id].extra) {
         if (pkt->type == prev_pkt[pkt->channel_id].type &&
             pkt->size == prev_pkt[pkt->channel_id].size) {
             mode = RTMP_PS_FOURBYTES;
             if (pkt->ts_delta == prev_pkt[pkt->channel_id].ts_delta)
                 mode = RTMP_PS_ONEBYTE;
         } else {
             mode = RTMP_PS_EIGHTBYTES;
         }
     }

     if (pkt->channel_id < 64) {
         bytestream_put_byte(&p, pkt->channel_id | (mode << 6));
     } else if (pkt->channel_id < 64 + 256) {
         bytestream_put_byte(&p, 0               | (mode << 6));
         bytestream_put_byte(&p, pkt->channel_id - 64);
     } else {
         bytestream_put_byte(&p, 1               | (mode << 6));
         bytestream_put_le16(&p, pkt->channel_id - 64);
     }
     if (mode != RTMP_PS_ONEBYTE) {
         uint32_t timestamp = pkt->timestamp;
         if (mode != RTMP_PS_TWELVEBYTES)
             timestamp = pkt->ts_delta;
         bytestream_put_be24(&p, timestamp >= 0xFFFFFF ? 0xFFFFFF : timestamp);
         if (mode != RTMP_PS_FOURBYTES) {
             bytestream_put_be24(&p, pkt->size);
             bytestream_put_byte(&p, pkt->type);
             if (mode == RTMP_PS_TWELVEBYTES)
                 bytestream_put_le32(&p, pkt->extra);
         }
         if (timestamp >= 0xFFFFFF)
             bytestream_put_be32(&p, timestamp);
     }
     // save history
     prev_pkt[pkt->channel_id].channel_id = pkt->channel_id;
     prev_pkt[pkt->channel_id].type       = pkt->type;
     prev_pkt[pkt->channel_id].size  = pkt->size;
     prev_pkt[pkt->channel_id].timestamp  = pkt->timestamp;
     if (mode != RTMP_PS_TWELVEBYTES) {
         prev_pkt[pkt->channel_id].ts_delta   = pkt->ts_delta;
     } else {
         prev_pkt[pkt->channel_id].ts_delta   = pkt->timestamp;
     }
     prev_pkt[pkt->channel_id].extra      = pkt->extra;

     ffurl_write(h, pkt_hdr, p-pkt_hdr);
     written = p - pkt_hdr + pkt->size;
     while (off < pkt->size) {
         int towrite = FFMIN(chunk_size, pkt->size - off);
         ffurl_write(h, pkt->data + off, towrite);
         off += towrite;
         if (off < pkt->size) {
             uint8_t marker = 0xC0 | pkt->channel_id;
             ffurl_write(h, &marker, 1);
             written++;
         }
     }
     return written;
 }

 int ff_rtmp_packet_create(RTMPPacket *pkt, int channel_id, RTMPPacketType type,
                           int timestamp, int size)
 {
     if (size) {
         pkt->data = av_malloc(size);
         if (!pkt->data)
             return AVERROR(ENOMEM);
     }
     pkt->size  = size;
     pkt->channel_id = channel_id;
     pkt->type       = type;
     pkt->timestamp  = timestamp;
     pkt->extra      = 0;
     pkt->ts_delta   = 0;

     return 0;
 }

 void ff_rtmp_packet_destroy(RTMPPacket *pkt)
 {
     if (!pkt)
         return;
     av_freep(&pkt->data);
     pkt->size = 0;
 }

 int ff_amf_tag_size(const uint8_t *data, const uint8_t *data_end)
 {
     const uint8_t *base = data;

     if (data >= data_end)
         return -1;
     switch (*data++) {
     case AMF_DATA_TYPE_NUMBER:      return 9;
     case AMF_DATA_TYPE_BOOL:        return 2;
     case AMF_DATA_TYPE_STRING:      return 3 + AV_RB16(data);
     case AMF_DATA_TYPE_LONG_STRING: return 5 + AV_RB32(data);
     case AMF_DATA_TYPE_NULL:        return 1;
     case AMF_DATA_TYPE_ARRAY:
         data += 4;
     case AMF_DATA_TYPE_OBJECT:
         for (;;) {
             int size = bytestream_get_be16(&data);
             int t;
             if (!size) {
                 data++;
                 break;
             }
             if (size < 0 || size >= data_end - data)
                 return -1;
             data += size;
             t = ff_amf_tag_size(data, data_end);
             if (t < 0 || t >= data_end - data)
                 return -1;
             data += t;
         }
         return data - base;
     case AMF_DATA_TYPE_OBJECT_END:  return 1;
     default:                        return -1;
     }
 }

 int ff_amf_get_field_value(const uint8_t *data, const uint8_t *data_end,
                            const uint8_t *name, uint8_t *dst, int dst_size)
 {
     int namelen = strlen(name);
     int len;

     while (*data != AMF_DATA_TYPE_OBJECT && data < data_end) {
         len = ff_amf_tag_size(data, data_end);
         if (len < 0)
             len = data_end - data;
         data += len;
     }
     if (data_end - data < 3)
         return -1;
     data++;
     for (;;) {
         int size = bytestream_get_be16(&data);
         if (!size)
             break;
         if (size < 0 || size >= data_end - data)
             return -1;
         data += size;
         if (size == namelen && !memcmp(data-size, name, namelen)) {
             switch (*data++) {
             case AMF_DATA_TYPE_NUMBER:
                 snprintf(dst, dst_size, "%g", av_int2double(AV_RB64(data)));
                 break;
             case AMF_DATA_TYPE_BOOL:
                 snprintf(dst, dst_size, "%s", *data ? "true" : "false");
                 break;
             case AMF_DATA_TYPE_STRING:
                 len = bytestream_get_be16(&data);
                 av_strlcpy(dst, data, FFMIN(len+1, dst_size));
                 break;
             default:
                 return -1;
             }
             return 0;
         }
         len = ff_amf_tag_size(data, data_end);
         if (len < 0 || len >= data_end - data)
             return -1;
         data += len;
     }
     return -1;
 }

 static const char* rtmp_packet_type(int type)
 {
     switch (type) {
     case RTMP_PT_CHUNK_SIZE:     return "chunk size";
     case RTMP_PT_BYTES_READ:     return "bytes read";
     case RTMP_PT_PING:           return "ping";
     case RTMP_PT_SERVER_BW:      return "server bandwidth";
     case RTMP_PT_CLIENT_BW:      return "client bandwidth";
     case RTMP_PT_AUDIO:          return "audio packet";
     case RTMP_PT_VIDEO:          return "video packet";
     case RTMP_PT_FLEX_STREAM:    return "Flex shared stream";
     case RTMP_PT_FLEX_OBJECT:    return "Flex shared object";
     case RTMP_PT_FLEX_MESSAGE:   return "Flex shared message";
     case RTMP_PT_NOTIFY:         return "notification";
     case RTMP_PT_SHARED_OBJ:     return "shared object";
     case RTMP_PT_INVOKE:         return "invoke";
     case RTMP_PT_METADATA:       return "metadata";
     default:                     return "unknown";
     }
 }

 static void ff_amf_tag_contents(void *ctx, const uint8_t *data, const uint8_t *data_end)
 {
     unsigned int size;
     char buf[1024];

     if (data >= data_end)
         return;
     switch (*data++) {
     case AMF_DATA_TYPE_NUMBER:
         av_log(ctx, AV_LOG_DEBUG, " number %g\n", av_int2double(AV_RB64(data)));
         return;
     case AMF_DATA_TYPE_BOOL:
         av_log(ctx, AV_LOG_DEBUG, " bool %d\n", *data);
         return;
     case AMF_DATA_TYPE_STRING:
     case AMF_DATA_TYPE_LONG_STRING:
         if (data[-1] == AMF_DATA_TYPE_STRING) {
             size = bytestream_get_be16(&data);
         } else {
             size = bytestream_get_be32(&data);
         }
         size = FFMIN(size, sizeof(buf) - 1);
         memcpy(buf, data, size);
         buf[size] = 0;
         av_log(ctx, AV_LOG_DEBUG, " string '%s'\n", buf);
         return;
     case AMF_DATA_TYPE_NULL:
         av_log(ctx, AV_LOG_DEBUG, " NULL\n");
         return;
     case AMF_DATA_TYPE_ARRAY:
         data += 4;
     case AMF_DATA_TYPE_OBJECT:
         av_log(ctx, AV_LOG_DEBUG, " {\n");
         for (;;) {
             int t;
             size = bytestream_get_be16(&data);
             av_strlcpy(buf, data, FFMIN(sizeof(buf), size + 1));
             if (!size) {
                 av_log(ctx, AV_LOG_DEBUG, " }\n");
                 data++;
                 break;
             }
             if (size >= data_end - data)
                 return;
             data += size;
             av_log(ctx, AV_LOG_DEBUG, "  %s: ", buf);
             ff_amf_tag_contents(ctx, data, data_end);
             t = ff_amf_tag_size(data, data_end);
             if (t < 0 || t >= data_end - data)
                 return;
             data += t;
         }
         return;
     case AMF_DATA_TYPE_OBJECT_END:
         av_log(ctx, AV_LOG_DEBUG, " }\n");
         return;
     default:
         return;
     }
 }

 void ff_rtmp_packet_dump(void *ctx, RTMPPacket *p)
 {
     av_log(ctx, AV_LOG_DEBUG, "RTMP packet type '%s'(%d) for channel %d, timestamp %d, extra field %d size %d\n",
            rtmp_packet_type(p->type), p->type, p->channel_id, p->timestamp, p->extra, p->size);
     if (p->type == RTMP_PT_INVOKE || p->type == RTMP_PT_NOTIFY) {
         uint8_t *src = p->data, *src_end = p->data + p->size;
         while (src < src_end) {
             int sz;
             ff_amf_tag_contents(ctx, src, src_end);
             sz = ff_amf_tag_size(src, src_end);
             if (sz < 0)
                 break;
             src += sz;
         }
     } else if (p->type == RTMP_PT_SERVER_BW){
         av_log(ctx, AV_LOG_DEBUG, "Server BW = %d\n", AV_RB32(p->data));
     } else if (p->type == RTMP_PT_CLIENT_BW){
         av_log(ctx, AV_LOG_DEBUG, "Client BW = %d\n", AV_RB32(p->data));
     } else if (p->type != RTMP_PT_AUDIO && p->type != RTMP_PT_VIDEO && p->type != RTMP_PT_METADATA) {
         int i;
         for (i = 0; i < p->size; i++)
             av_log(ctx, AV_LOG_DEBUG, " %02X", p->data[i]);
         av_log(ctx, AV_LOG_DEBUG, "\n");
     }
 }

 int ff_amf_match_string(const uint8_t *data, int size, const char *str)
 {
     int len = strlen(str);
     int amf_len, type;

     if (size < 1)
         return 0;

     type = *data++;

     if (type != AMF_DATA_TYPE_LONG_STRING &&
         type != AMF_DATA_TYPE_STRING)
         return 0;

     if (type == AMF_DATA_TYPE_LONG_STRING) {
         if ((size -= 4 + 1) < 0)
             return 0;
         amf_len = bytestream_get_be32(&data);
     } else {
         if ((size -= 2 + 1) < 0)
             return 0;
         amf_len = bytestream_get_be16(&data);
     }

     if (amf_len > size)
         return 0;

     if (amf_len != len)
         return 0;

     return !memcmp(data, str, len);
 }
	/*
	* RTMP input format
	* Copyright (c) 2009 Kostya Shishkov
	*
	* 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 "libavcodec/bytestream.h"
	#include "libavutil/avstring.h"
	#include "libavutil/intfloat.h"
	#include "avformat.h"

	#include "rtmppkt.h"
	#include "flv.h"
	#include "url.h"

	void ff_amf_write_bool(uint8_t **dst, int val)
	{
	bytestream_put_byte(dst, AMF_DATA_TYPE_BOOL);
	bytestream_put_byte(dst, val);
	}

	void ff_amf_write_number(uint8_t **dst, double val)
	{
	bytestream_put_byte(dst, AMF_DATA_TYPE_NUMBER);
	bytestream_put_be64(dst, av_double2int(val));
	}

	void ff_amf_write_string(uint8_t *dst, const char str)
	{
	bytestream_put_byte(dst, AMF_DATA_TYPE_STRING);
	bytestream_put_be16(dst, strlen(str));
	bytestream_put_buffer(dst, str, strlen(str));
	}

	void ff_amf_write_null(uint8_t **dst)
	{
	bytestream_put_byte(dst, AMF_DATA_TYPE_NULL);
	}

	void ff_amf_write_object_start(uint8_t **dst)
	{
	bytestream_put_byte(dst, AMF_DATA_TYPE_OBJECT);
	}

	void ff_amf_write_field_name(uint8_t *dst, const char str)
	{
	bytestream_put_be16(dst, strlen(str));
	bytestream_put_buffer(dst, str, strlen(str));
	}

	void ff_amf_write_object_end(uint8_t **dst)
	{
	/* first two bytes are field name length = 0,
	* AMF object should end with it and end marker
	*/
	bytestream_put_be24(dst, AMF_DATA_TYPE_OBJECT_END);
	}

	int ff_rtmp_packet_read(URLContext h, RTMPPacket p,
	int chunk_size, RTMPPacket *prev_pkt)
	{
	uint8_t hdr, t, buf[16];
	int channel_id, timestamp, size, offset = 0;
	uint32_t extra = 0;
	enum RTMPPacketType type;
	int written = 0;

	if (ffurl_read(h, &hdr, 1) != 1)
	return AVERROR(EIO);
	written++;
	channel_id = hdr & 0x3F;

	if (channel_id < 2) { //special case for channel number >= 64
	buf[1] = 0;
	if (ffurl_read_complete(h, buf, channel_id + 1) != channel_id + 1)
	return AVERROR(EIO);
	written += channel_id + 1;
	channel_id = AV_RL16(buf) + 64;
	}
	size = prev_pkt[channel_id].size;
	type = prev_pkt[channel_id].type;
	extra = prev_pkt[channel_id].extra;

	hdr >>= 6;
	if (hdr == RTMP_PS_ONEBYTE) {
	timestamp = prev_pkt[channel_id].ts_delta;
	} else {
	if (ffurl_read_complete(h, buf, 3) != 3)
	return AVERROR(EIO);
	written += 3;
	timestamp = AV_RB24(buf);
	if (hdr != RTMP_PS_FOURBYTES) {
	if (ffurl_read_complete(h, buf, 3) != 3)
	return AVERROR(EIO);
	written += 3;
	size = AV_RB24(buf);
	if (ffurl_read_complete(h, buf, 1) != 1)
	return AVERROR(EIO);
	written++;
	type = buf[0];
	if (hdr == RTMP_PS_TWELVEBYTES) {
	if (ffurl_read_complete(h, buf, 4) != 4)
	return AVERROR(EIO);
	written += 4;
	extra = AV_RL32(buf);
	}
	}
	if (timestamp == 0xFFFFFF) {
	if (ffurl_read_complete(h, buf, 4) != 4)
	return AVERROR(EIO);
	timestamp = AV_RB32(buf);
	}
	}
	if (hdr != RTMP_PS_TWELVEBYTES)
	timestamp += prev_pkt[channel_id].timestamp;

	if (ff_rtmp_packet_create(p, channel_id, type, timestamp, size))
	return -1;
	p->extra = extra;
	// save history
	prev_pkt[channel_id].channel_id = channel_id;
	prev_pkt[channel_id].type = type;
	prev_pkt[channel_id].size = size;
	prev_pkt[channel_id].ts_delta = timestamp - prev_pkt[channel_id].timestamp;
	prev_pkt[channel_id].timestamp = timestamp;
	prev_pkt[channel_id].extra = extra;
	while (size > 0) {
	int toread = FFMIN(size, chunk_size);
	if (ffurl_read_complete(h, p->data + offset, toread) != toread) {
	ff_rtmp_packet_destroy(p);
	return AVERROR(EIO);
	}
	size -= chunk_size;
	offset += chunk_size;
	written += chunk_size;
	if (size > 0) {
	ffurl_read_complete(h, &t, 1); //marker
	written++;
	if (t != (0xC0 + channel_id))
	return -1;
	}
	}
	return written;
	}

	int ff_rtmp_packet_write(URLContext h, RTMPPacket pkt,
	int chunk_size, RTMPPacket *prev_pkt)
	{
	uint8_t pkt_hdr[16], *p = pkt_hdr;
	int mode = RTMP_PS_TWELVEBYTES;
	int off = 0;
	int written = 0;

	pkt->ts_delta = pkt->timestamp - prev_pkt[pkt->channel_id].timestamp;

	//if channel_id = 0, this is first presentation of prev_pkt, send full hdr.
	if (prev_pkt[pkt->channel_id].channel_id &&
	pkt->extra == prev_pkt[pkt->channel_id].extra) {
	if (pkt->type == prev_pkt[pkt->channel_id].type &&
	pkt->size == prev_pkt[pkt->channel_id].size) {
	mode = RTMP_PS_FOURBYTES;
	if (pkt->ts_delta == prev_pkt[pkt->channel_id].ts_delta)
	mode = RTMP_PS_ONEBYTE;
	} else {
	mode = RTMP_PS_EIGHTBYTES;
	}
	}

	if (pkt->channel_id < 64) {
	bytestream_put_byte(&p, pkt->channel_id \| (mode << 6));
	} else if (pkt->channel_id < 64 + 256) {
	bytestream_put_byte(&p, 0 \| (mode << 6));
	bytestream_put_byte(&p, pkt->channel_id - 64);
	} else {
	bytestream_put_byte(&p, 1 \| (mode << 6));
	bytestream_put_le16(&p, pkt->channel_id - 64);
	}
	if (mode != RTMP_PS_ONEBYTE) {
	uint32_t timestamp = pkt->timestamp;
	if (mode != RTMP_PS_TWELVEBYTES)
	timestamp = pkt->ts_delta;
	bytestream_put_be24(&p, timestamp >= 0xFFFFFF ? 0xFFFFFF : timestamp);
	if (mode != RTMP_PS_FOURBYTES) {
	bytestream_put_be24(&p, pkt->size);
	bytestream_put_byte(&p, pkt->type);
	if (mode == RTMP_PS_TWELVEBYTES)
	bytestream_put_le32(&p, pkt->extra);
	}
	if (timestamp >= 0xFFFFFF)
	bytestream_put_be32(&p, timestamp);
	}
	// save history
	prev_pkt[pkt->channel_id].channel_id = pkt->channel_id;
	prev_pkt[pkt->channel_id].type = pkt->type;
	prev_pkt[pkt->channel_id].size = pkt->size;
	prev_pkt[pkt->channel_id].timestamp = pkt->timestamp;
	if (mode != RTMP_PS_TWELVEBYTES) {
	prev_pkt[pkt->channel_id].ts_delta = pkt->ts_delta;
	} else {
	prev_pkt[pkt->channel_id].ts_delta = pkt->timestamp;
	}
	prev_pkt[pkt->channel_id].extra = pkt->extra;

	ffurl_write(h, pkt_hdr, p-pkt_hdr);
	written = p - pkt_hdr + pkt->size;
	while (off < pkt->size) {
	int towrite = FFMIN(chunk_size, pkt->size - off);
	ffurl_write(h, pkt->data + off, towrite);
	off += towrite;
	if (off < pkt->size) {
	uint8_t marker = 0xC0 \| pkt->channel_id;
	ffurl_write(h, &marker, 1);
	written++;
	}
	}
	return written;
	}

	int ff_rtmp_packet_create(RTMPPacket *pkt, int channel_id, RTMPPacketType type,
	int timestamp, int size)
	{
	if (size) {
	pkt->data = av_malloc(size);
	if (!pkt->data)
	return AVERROR(ENOMEM);
	}
	pkt->size = size;
	pkt->channel_id = channel_id;
	pkt->type = type;
	pkt->timestamp = timestamp;
	pkt->extra = 0;
	pkt->ts_delta = 0;

	return 0;
	}

	void ff_rtmp_packet_destroy(RTMPPacket *pkt)
	{
	if (!pkt)
	return;
	av_freep(&pkt->data);
	pkt->size = 0;
	}

	int ff_amf_tag_size(const uint8_t data, const uint8_t data_end)
	{
	const uint8_t *base = data;

	if (data >= data_end)
	return -1;
	switch (*data++) {
	case AMF_DATA_TYPE_NUMBER: return 9;
	case AMF_DATA_TYPE_BOOL: return 2;
	case AMF_DATA_TYPE_STRING: return 3 + AV_RB16(data);
	case AMF_DATA_TYPE_LONG_STRING: return 5 + AV_RB32(data);
	case AMF_DATA_TYPE_NULL: return 1;
	case AMF_DATA_TYPE_ARRAY:
	data += 4;
	case AMF_DATA_TYPE_OBJECT:
	for (;;) {
	int size = bytestream_get_be16(&data);
	int t;
	if (!size) {
	data++;
	break;
	}
	if (size < 0 \|\| size >= data_end - data)
	return -1;
	data += size;
	t = ff_amf_tag_size(data, data_end);
	if (t < 0 \|\| t >= data_end - data)
	return -1;
	data += t;
	}
	return data - base;
	case AMF_DATA_TYPE_OBJECT_END: return 1;
	default: return -1;
	}
	}

	int ff_amf_get_field_value(const uint8_t data, const uint8_t data_end,
	const uint8_t name, uint8_t dst, int dst_size)
	{
	int namelen = strlen(name);
	int len;

	while (*data != AMF_DATA_TYPE_OBJECT && data < data_end) {
	len = ff_amf_tag_size(data, data_end);
	if (len < 0)
	len = data_end - data;
	data += len;
	}
	if (data_end - data < 3)
	return -1;
	data++;
	for (;;) {
	int size = bytestream_get_be16(&data);
	if (!size)
	break;
	if (size < 0 \|\| size >= data_end - data)
	return -1;
	data += size;
	if (size == namelen && !memcmp(data-size, name, namelen)) {
	switch (*data++) {
	case AMF_DATA_TYPE_NUMBER:
	snprintf(dst, dst_size, "%g", av_int2double(AV_RB64(data)));
	break;
	case AMF_DATA_TYPE_BOOL:
	snprintf(dst, dst_size, "%s", *data ? "true" : "false");
	break;
	case AMF_DATA_TYPE_STRING:
	len = bytestream_get_be16(&data);
	av_strlcpy(dst, data, FFMIN(len+1, dst_size));
	break;
	default:
	return -1;
	}
	return 0;
	}
	len = ff_amf_tag_size(data, data_end);
	if (len < 0 \|\| len >= data_end - data)
	return -1;
	data += len;
	}
	return -1;
	}

	static const char* rtmp_packet_type(int type)
	{
	switch (type) {
	case RTMP_PT_CHUNK_SIZE: return "chunk size";
	case RTMP_PT_BYTES_READ: return "bytes read";
	case RTMP_PT_PING: return "ping";
	case RTMP_PT_SERVER_BW: return "server bandwidth";
	case RTMP_PT_CLIENT_BW: return "client bandwidth";
	case RTMP_PT_AUDIO: return "audio packet";
	case RTMP_PT_VIDEO: return "video packet";
	case RTMP_PT_FLEX_STREAM: return "Flex shared stream";
	case RTMP_PT_FLEX_OBJECT: return "Flex shared object";
	case RTMP_PT_FLEX_MESSAGE: return "Flex shared message";
	case RTMP_PT_NOTIFY: return "notification";
	case RTMP_PT_SHARED_OBJ: return "shared object";
	case RTMP_PT_INVOKE: return "invoke";
	case RTMP_PT_METADATA: return "metadata";
	default: return "unknown";
	}
	}

	static void ff_amf_tag_contents(void ctx, const uint8_t data, const uint8_t *data_end)
	{
	unsigned int size;
	char buf[1024];

	if (data >= data_end)
	return;
	switch (*data++) {
	case AMF_DATA_TYPE_NUMBER:
	av_log(ctx, AV_LOG_DEBUG, " number %g\n", av_int2double(AV_RB64(data)));
	return;
	case AMF_DATA_TYPE_BOOL:
	av_log(ctx, AV_LOG_DEBUG, " bool %d\n", *data);
	return;
	case AMF_DATA_TYPE_STRING:
	case AMF_DATA_TYPE_LONG_STRING:
	if (data[-1] == AMF_DATA_TYPE_STRING) {
	size = bytestream_get_be16(&data);
	} else {
	size = bytestream_get_be32(&data);
	}
	size = FFMIN(size, sizeof(buf) - 1);
	memcpy(buf, data, size);
	buf[size] = 0;
	av_log(ctx, AV_LOG_DEBUG, " string '%s'\n", buf);
	return;
	case AMF_DATA_TYPE_NULL:
	av_log(ctx, AV_LOG_DEBUG, " NULL\n");
	return;
	case AMF_DATA_TYPE_ARRAY:
	data += 4;
	case AMF_DATA_TYPE_OBJECT:
	av_log(ctx, AV_LOG_DEBUG, " {\n");
	for (;;) {
	int t;
	size = bytestream_get_be16(&data);
	av_strlcpy(buf, data, FFMIN(sizeof(buf), size + 1));
	if (!size) {
	av_log(ctx, AV_LOG_DEBUG, " }\n");
	data++;
	break;
	}
	if (size >= data_end - data)
	return;
	data += size;
	av_log(ctx, AV_LOG_DEBUG, " %s: ", buf);
	ff_amf_tag_contents(ctx, data, data_end);
	t = ff_amf_tag_size(data, data_end);
	if (t < 0 \|\| t >= data_end - data)
	return;
	data += t;
	}
	return;
	case AMF_DATA_TYPE_OBJECT_END:
	av_log(ctx, AV_LOG_DEBUG, " }\n");
	return;
	default:
	return;
	}
	}

	void ff_rtmp_packet_dump(void ctx, RTMPPacket p)
	{
	av_log(ctx, AV_LOG_DEBUG, "RTMP packet type '%s'(%d) for channel %d, timestamp %d, extra field %d size %d\n",
	rtmp_packet_type(p->type), p->type, p->channel_id, p->timestamp, p->extra, p->size);
	if (p->type == RTMP_PT_INVOKE \|\| p->type == RTMP_PT_NOTIFY) {
	uint8_t src = p->data, src_end = p->data + p->size;
	while (src < src_end) {
	int sz;
	ff_amf_tag_contents(ctx, src, src_end);
	sz = ff_amf_tag_size(src, src_end);
	if (sz < 0)
	break;
	src += sz;
	}
	} else if (p->type == RTMP_PT_SERVER_BW){
	av_log(ctx, AV_LOG_DEBUG, "Server BW = %d\n", AV_RB32(p->data));
	} else if (p->type == RTMP_PT_CLIENT_BW){
	av_log(ctx, AV_LOG_DEBUG, "Client BW = %d\n", AV_RB32(p->data));
	} else if (p->type != RTMP_PT_AUDIO && p->type != RTMP_PT_VIDEO && p->type != RTMP_PT_METADATA) {
	int i;
	for (i = 0; i < p->size; i++)
	av_log(ctx, AV_LOG_DEBUG, " %02X", p->data[i]);
	av_log(ctx, AV_LOG_DEBUG, "\n");
	}
	}

	int ff_amf_match_string(const uint8_t data, int size, const char str)
	{
	int len = strlen(str);
	int amf_len, type;

	if (size < 1)
	return 0;

	type = *data++;

	if (type != AMF_DATA_TYPE_LONG_STRING &&
	type != AMF_DATA_TYPE_STRING)
	return 0;

	if (type == AMF_DATA_TYPE_LONG_STRING) {
	if ((size -= 4 + 1) < 0)
	return 0;
	amf_len = bytestream_get_be32(&data);
	} else {
	if ((size -= 2 + 1) < 0)
	return 0;
	amf_len = bytestream_get_be16(&data);
	}

	if (amf_len > size)
	return 0;

	if (amf_len != len)
	return 0;

	return !memcmp(data, str, len);
	}