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libavformat/rtpdec_xiph.c

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00001 /*
00002  * Xiph RTP Protocols
00003  * Copyright (c) 2009 Colin McQuillian
00004  * Copyright (c) 2010 Josh Allmann
00005  *
00006  * This file is part of Libav.
00007  *
00008  * Libav is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * Libav is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with Libav; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00030 #include "libavutil/avstring.h"
00031 #include "libavutil/base64.h"
00032 #include "libavcodec/bytestream.h"
00033 
00034 #include <assert.h>
00035 
00036 #include "rtpdec.h"
00037 #include "rtpdec_formats.h"
00038 
00042 struct PayloadContext {
00043     unsigned ident;             
00044     uint32_t timestamp;
00045     AVIOContext* fragment;    
00046     uint8_t *split_buf;
00047     int split_pos, split_buf_len, split_buf_size;
00048     int split_pkts;
00049 };
00050 
00051 static PayloadContext *xiph_new_context(void)
00052 {
00053     return av_mallocz(sizeof(PayloadContext));
00054 }
00055 
00056 static inline void free_fragment_if_needed(PayloadContext * data)
00057 {
00058     if (data->fragment) {
00059         uint8_t* p;
00060         avio_close_dyn_buf(data->fragment, &p);
00061         av_free(p);
00062         data->fragment = NULL;
00063     }
00064 }
00065 
00066 static void xiph_free_context(PayloadContext * data)
00067 {
00068     free_fragment_if_needed(data);
00069     av_free(data->split_buf);
00070     av_free(data);
00071 }
00072 
00073 static int xiph_handle_packet(AVFormatContext * ctx,
00074                               PayloadContext * data,
00075                               AVStream * st,
00076                               AVPacket * pkt,
00077                               uint32_t * timestamp,
00078                               const uint8_t * buf, int len, int flags)
00079 {
00080 
00081     int ident, fragmented, tdt, num_pkts, pkt_len;
00082 
00083     if (!buf) {
00084         if (!data->split_buf || data->split_pos + 2 > data->split_buf_len ||
00085             data->split_pkts <= 0) {
00086             av_log(ctx, AV_LOG_ERROR, "No more data to return\n");
00087             return AVERROR_INVALIDDATA;
00088         }
00089         pkt_len = AV_RB16(data->split_buf + data->split_pos);
00090         data->split_pos += 2;
00091         if (data->split_pos + pkt_len > data->split_buf_len) {
00092             av_log(ctx, AV_LOG_ERROR, "Not enough data to return\n");
00093             return AVERROR_INVALIDDATA;
00094         }
00095         if (av_new_packet(pkt, pkt_len)) {
00096             av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
00097             return AVERROR(ENOMEM);
00098         }
00099         pkt->stream_index = st->index;
00100         memcpy(pkt->data, data->split_buf + data->split_pos, pkt_len);
00101         data->split_pos += pkt_len;
00102         data->split_pkts--;
00103         return data->split_pkts > 0;
00104     }
00105 
00106     if (len < 6) {
00107         av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
00108         return AVERROR_INVALIDDATA;
00109     }
00110 
00111     // read xiph rtp headers
00112     ident       = AV_RB24(buf);
00113     fragmented  = buf[3] >> 6;
00114     tdt         = (buf[3] >> 4) & 3;
00115     num_pkts    = buf[3] & 0xf;
00116     pkt_len     = AV_RB16(buf + 4);
00117 
00118     if (pkt_len > len - 6) {
00119         av_log(ctx, AV_LOG_ERROR,
00120                "Invalid packet length %d in %d byte packet\n", pkt_len,
00121                len);
00122         return AVERROR_INVALIDDATA;
00123     }
00124 
00125     if (ident != data->ident) {
00126         av_log(ctx, AV_LOG_ERROR,
00127                "Unimplemented Xiph SDP configuration change detected\n");
00128         return AVERROR_PATCHWELCOME;
00129     }
00130 
00131     if (tdt) {
00132         av_log(ctx, AV_LOG_ERROR,
00133                "Unimplemented RTP Xiph packet settings (%d,%d,%d)\n",
00134                fragmented, tdt, num_pkts);
00135         return AVERROR_PATCHWELCOME;
00136     }
00137 
00138     buf += 6; // move past header bits
00139     len -= 6;
00140 
00141     if (fragmented == 0) {
00142         if (av_new_packet(pkt, pkt_len)) {
00143             av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
00144             return AVERROR(ENOMEM);
00145         }
00146         pkt->stream_index = st->index;
00147         memcpy(pkt->data, buf, pkt_len);
00148         buf += pkt_len;
00149         len -= pkt_len;
00150         num_pkts--;
00151 
00152         if (num_pkts > 0) {
00153             if (len > data->split_buf_size || !data->split_buf) {
00154                 av_freep(&data->split_buf);
00155                 data->split_buf_size = 2 * len;
00156                 data->split_buf = av_malloc(data->split_buf_size);
00157                 if (!data->split_buf) {
00158                     av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
00159                     av_free_packet(pkt);
00160                     return AVERROR(ENOMEM);
00161                 }
00162             }
00163             memcpy(data->split_buf, buf, len);
00164             data->split_buf_len = len;
00165             data->split_pos = 0;
00166             data->split_pkts = num_pkts;
00167             return 1;
00168         }
00169 
00170         return 0;
00171 
00172     } else if (fragmented == 1) {
00173         // start of xiph data fragment
00174         int res;
00175 
00176         // end packet has been lost somewhere, so drop buffered data
00177         free_fragment_if_needed(data);
00178 
00179         if((res = avio_open_dyn_buf(&data->fragment)) < 0)
00180             return res;
00181 
00182         avio_write(data->fragment, buf, pkt_len);
00183         data->timestamp = *timestamp;
00184 
00185     } else {
00186         assert(fragmented < 4);
00187         if (data->timestamp != *timestamp) {
00188             // skip if fragmented timestamp is incorrect;
00189             // a start packet has been lost somewhere
00190             free_fragment_if_needed(data);
00191             av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
00192             return AVERROR_INVALIDDATA;
00193         }
00194         if (!data->fragment) {
00195             av_log(ctx, AV_LOG_WARNING,
00196                    "Received packet without a start fragment; dropping.\n");
00197             return AVERROR(EAGAIN);
00198         }
00199 
00200         // copy data to fragment buffer
00201         avio_write(data->fragment, buf, pkt_len);
00202 
00203         if (fragmented == 3) {
00204             // end of xiph data packet
00205             av_init_packet(pkt);
00206             pkt->size = avio_close_dyn_buf(data->fragment, &pkt->data);
00207 
00208             if (pkt->size < 0) {
00209                 av_log(ctx, AV_LOG_ERROR,
00210                        "Error occurred when getting fragment buffer.");
00211                 return pkt->size;
00212             }
00213 
00214             pkt->stream_index = st->index;
00215             pkt->destruct = av_destruct_packet;
00216 
00217             data->fragment = NULL;
00218 
00219             return 0;
00220         }
00221     }
00222 
00223    return AVERROR(EAGAIN);
00224 }
00225 
00229 static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
00230 {
00231     int n = 0;
00232     for (; *buf < buf_end; ++*buf) {
00233         n <<= 7;
00234         n += **buf & 0x7f;
00235         if (!(**buf & 0x80)) {
00236             ++*buf;
00237             return n;
00238         }
00239     }
00240     return 0;
00241 }
00242 
00246 static unsigned int
00247 parse_packed_headers(const uint8_t * packed_headers,
00248                      const uint8_t * packed_headers_end,
00249                      AVCodecContext * codec, PayloadContext * xiph_data)
00250 {
00251 
00252     unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
00253     uint8_t *ptr;
00254 
00255     if (packed_headers_end - packed_headers < 9) {
00256         av_log(codec, AV_LOG_ERROR,
00257                "Invalid %td byte packed header.",
00258                packed_headers_end - packed_headers);
00259         return AVERROR_INVALIDDATA;
00260     }
00261 
00262     num_packed         = bytestream_get_be32(&packed_headers);
00263     xiph_data->ident   = bytestream_get_be24(&packed_headers);
00264     length             = bytestream_get_be16(&packed_headers);
00265     num_headers        = get_base128(&packed_headers, packed_headers_end);
00266     length1            = get_base128(&packed_headers, packed_headers_end);
00267     length2            = get_base128(&packed_headers, packed_headers_end);
00268 
00269     if (num_packed != 1 || num_headers > 3) {
00270         av_log(codec, AV_LOG_ERROR,
00271                "Unimplemented number of headers: %d packed headers, %d headers\n",
00272                num_packed, num_headers);
00273         return AVERROR_PATCHWELCOME;
00274     }
00275 
00276     if (packed_headers_end - packed_headers != length ||
00277         length1 > length || length2 > length - length1) {
00278         av_log(codec, AV_LOG_ERROR,
00279                "Bad packed header lengths (%d,%d,%td,%d)\n", length1,
00280                length2, packed_headers_end - packed_headers, length);
00281         return AVERROR_INVALIDDATA;
00282     }
00283 
00284     /* allocate extra space:
00285      * -- length/255 +2 for xiphlacing
00286      * -- one for the '2' marker
00287      * -- FF_INPUT_BUFFER_PADDING_SIZE required */
00288     extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;
00289 
00290     ptr = codec->extradata = av_malloc(extradata_alloc);
00291     if (!ptr) {
00292         av_log(codec, AV_LOG_ERROR, "Out of memory\n");
00293         return AVERROR(ENOMEM);
00294     }
00295     *ptr++ = 2;
00296     ptr += av_xiphlacing(ptr, length1);
00297     ptr += av_xiphlacing(ptr, length2);
00298     memcpy(ptr, packed_headers, length);
00299     ptr += length;
00300     codec->extradata_size = ptr - codec->extradata;
00301     // clear out remaining parts of the buffer
00302     memset(ptr, 0, extradata_alloc - codec->extradata_size);
00303 
00304     return 0;
00305 }
00306 
00307 static int xiph_parse_fmtp_pair(AVStream* stream,
00308                                 PayloadContext *xiph_data,
00309                                 char *attr, char *value)
00310 {
00311     AVCodecContext *codec = stream->codec;
00312     int result = 0;
00313 
00314     if (!strcmp(attr, "sampling")) {
00315         if (!strcmp(value, "YCbCr-4:2:0")) {
00316             codec->pix_fmt = PIX_FMT_YUV420P;
00317         } else if (!strcmp(value, "YCbCr-4:4:2")) {
00318             codec->pix_fmt = PIX_FMT_YUV422P;
00319         } else if (!strcmp(value, "YCbCr-4:4:4")) {
00320             codec->pix_fmt = PIX_FMT_YUV444P;
00321         } else {
00322             av_log(codec, AV_LOG_ERROR,
00323                    "Unsupported pixel format %s\n", attr);
00324             return AVERROR_INVALIDDATA;
00325         }
00326     } else if (!strcmp(attr, "width")) {
00327         /* This is an integer between 1 and 1048561
00328          * and MUST be in multiples of 16. */
00329         codec->width = atoi(value);
00330         return 0;
00331     } else if (!strcmp(attr, "height")) {
00332         /* This is an integer between 1 and 1048561
00333          * and MUST be in multiples of 16. */
00334         codec->height = atoi(value);
00335         return 0;
00336     } else if (!strcmp(attr, "delivery-method")) {
00337         /* Possible values are: inline, in_band, out_band/specific_name. */
00338         return AVERROR_PATCHWELCOME;
00339     } else if (!strcmp(attr, "configuration-uri")) {
00340         /* NOTE: configuration-uri is supported only under 2 conditions:
00341          *--after the delivery-method tag
00342          * --with a delivery-method value of out_band */
00343         return AVERROR_PATCHWELCOME;
00344     } else if (!strcmp(attr, "configuration")) {
00345         /* NOTE: configuration is supported only AFTER the delivery-method tag
00346          * The configuration value is a base64 encoded packed header */
00347         uint8_t *decoded_packet = NULL;
00348         int packet_size;
00349         size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
00350 
00351         if (decoded_alloc <= INT_MAX) {
00352             decoded_packet = av_malloc(decoded_alloc);
00353             if (decoded_packet) {
00354                 packet_size =
00355                     av_base64_decode(decoded_packet, value, decoded_alloc);
00356 
00357                 result = parse_packed_headers
00358                     (decoded_packet, decoded_packet + packet_size, codec,
00359                     xiph_data);
00360             } else {
00361                 av_log(codec, AV_LOG_ERROR,
00362                        "Out of memory while decoding SDP configuration.\n");
00363                 result = AVERROR(ENOMEM);
00364             }
00365         } else {
00366             av_log(codec, AV_LOG_ERROR, "Packet too large\n");
00367             result = AVERROR_INVALIDDATA;
00368         }
00369         av_free(decoded_packet);
00370     }
00371     return result;
00372 }
00373 
00374 static int xiph_parse_sdp_line(AVFormatContext *s, int st_index,
00375                                  PayloadContext *data, const char *line)
00376 {
00377     const char *p;
00378 
00379     if (av_strstart(line, "fmtp:", &p)) {
00380         return ff_parse_fmtp(s->streams[st_index], data, p,
00381                              xiph_parse_fmtp_pair);
00382     }
00383 
00384     return 0;
00385 }
00386 
00387 RTPDynamicProtocolHandler ff_theora_dynamic_handler = {
00388     .enc_name         = "theora",
00389     .codec_type       = AVMEDIA_TYPE_VIDEO,
00390     .codec_id         = CODEC_ID_THEORA,
00391     .parse_sdp_a_line = xiph_parse_sdp_line,
00392     .alloc            = xiph_new_context,
00393     .free             = xiph_free_context,
00394     .parse_packet     = xiph_handle_packet
00395 };
00396 
00397 RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {
00398     .enc_name         = "vorbis",
00399     .codec_type       = AVMEDIA_TYPE_AUDIO,
00400     .codec_id         = CODEC_ID_VORBIS,
00401     .parse_sdp_a_line = xiph_parse_sdp_line,
00402     .alloc            = xiph_new_context,
00403     .free             = xiph_free_context,
00404     .parse_packet     = xiph_handle_packet
00405 };
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