Libav 0.7.1
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00001 00022 #include "rtpdec_formats.h" 00023 #include "internal.h" 00024 #include "libavutil/avstring.h" 00025 #include "libavcodec/get_bits.h" 00026 #include <strings.h> 00027 00028 struct PayloadContext { 00029 AVIOContext *dyn_buf; 00030 uint8_t *buf; 00031 int pos, len; 00032 uint32_t timestamp; 00033 }; 00034 00035 static PayloadContext *latm_new_context(void) 00036 { 00037 return av_mallocz(sizeof(PayloadContext)); 00038 } 00039 00040 static void latm_free_context(PayloadContext *data) 00041 { 00042 if (!data) 00043 return; 00044 if (data->dyn_buf) { 00045 uint8_t *p; 00046 avio_close_dyn_buf(data->dyn_buf, &p); 00047 av_free(p); 00048 } 00049 av_free(data->buf); 00050 av_free(data); 00051 } 00052 00053 static int latm_parse_packet(AVFormatContext *ctx, PayloadContext *data, 00054 AVStream *st, AVPacket *pkt, uint32_t *timestamp, 00055 const uint8_t *buf, int len, int flags) 00056 { 00057 int ret, cur_len; 00058 00059 if (buf) { 00060 if (!data->dyn_buf || data->timestamp != *timestamp) { 00061 av_freep(&data->buf); 00062 if (data->dyn_buf) 00063 avio_close_dyn_buf(data->dyn_buf, &data->buf); 00064 data->dyn_buf = NULL; 00065 av_freep(&data->buf); 00066 00067 data->timestamp = *timestamp; 00068 if ((ret = avio_open_dyn_buf(&data->dyn_buf)) < 0) 00069 return ret; 00070 } 00071 avio_write(data->dyn_buf, buf, len); 00072 00073 if (!(flags & RTP_FLAG_MARKER)) 00074 return AVERROR(EAGAIN); 00075 av_free(data->buf); 00076 data->len = avio_close_dyn_buf(data->dyn_buf, &data->buf); 00077 data->dyn_buf = NULL; 00078 data->pos = 0; 00079 } 00080 00081 if (!data->buf) { 00082 av_log(ctx, AV_LOG_ERROR, "No data available yet\n"); 00083 return AVERROR(EIO); 00084 } 00085 00086 cur_len = 0; 00087 while (data->pos < data->len) { 00088 uint8_t val = data->buf[data->pos++]; 00089 cur_len += val; 00090 if (val != 0xff) 00091 break; 00092 } 00093 if (data->pos + cur_len > data->len) { 00094 av_log(ctx, AV_LOG_ERROR, "Malformed LATM packet\n"); 00095 return AVERROR(EIO); 00096 } 00097 00098 if ((ret = av_new_packet(pkt, cur_len)) < 0) 00099 return ret; 00100 memcpy(pkt->data, data->buf + data->pos, cur_len); 00101 data->pos += cur_len; 00102 pkt->stream_index = st->index; 00103 return data->pos < data->len; 00104 } 00105 00106 static int parse_fmtp_config(AVStream *st, char *value) 00107 { 00108 int len = ff_hex_to_data(NULL, value), i, ret = 0; 00109 GetBitContext gb; 00110 uint8_t *config; 00111 int audio_mux_version, same_time_framing, num_programs, num_layers; 00112 00113 /* Pad this buffer, too, to avoid out of bounds reads with get_bits below */ 00114 config = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE); 00115 if (!config) 00116 return AVERROR(ENOMEM); 00117 ff_hex_to_data(config, value); 00118 init_get_bits(&gb, config, len*8); 00119 audio_mux_version = get_bits(&gb, 1); 00120 same_time_framing = get_bits(&gb, 1); 00121 skip_bits(&gb, 6); /* num_sub_frames */ 00122 num_programs = get_bits(&gb, 4); 00123 num_layers = get_bits(&gb, 3); 00124 if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 || 00125 num_layers != 0) { 00126 av_log(NULL, AV_LOG_WARNING, "Unsupported LATM config (%d,%d,%d,%d)\n", 00127 audio_mux_version, same_time_framing, 00128 num_programs, num_layers); 00129 ret = AVERROR_PATCHWELCOME; 00130 goto end; 00131 } 00132 av_freep(&st->codec->extradata); 00133 st->codec->extradata_size = (get_bits_left(&gb) + 7)/8; 00134 st->codec->extradata = av_mallocz(st->codec->extradata_size + 00135 FF_INPUT_BUFFER_PADDING_SIZE); 00136 if (!st->codec->extradata) { 00137 ret = AVERROR(ENOMEM); 00138 goto end; 00139 } 00140 for (i = 0; i < st->codec->extradata_size; i++) 00141 st->codec->extradata[i] = get_bits(&gb, 8); 00142 00143 end: 00144 av_free(config); 00145 return ret; 00146 } 00147 00148 static int parse_fmtp(AVStream *stream, PayloadContext *data, 00149 char *attr, char *value) 00150 { 00151 int res; 00152 00153 if (!strcmp(attr, "config")) { 00154 res = parse_fmtp_config(stream, value); 00155 if (res < 0) 00156 return res; 00157 } else if (!strcmp(attr, "cpresent")) { 00158 int cpresent = atoi(value); 00159 if (cpresent != 0) 00160 av_log_missing_feature(NULL, "RTP MP4A-LATM with in-band " 00161 "configuration", 1); 00162 } 00163 00164 return 0; 00165 } 00166 00167 static int latm_parse_sdp_line(AVFormatContext *s, int st_index, 00168 PayloadContext *data, const char *line) 00169 { 00170 const char *p; 00171 00172 if (av_strstart(line, "fmtp:", &p)) 00173 return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp); 00174 00175 return 0; 00176 } 00177 00178 RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = { 00179 .enc_name = "MP4A-LATM", 00180 .codec_type = AVMEDIA_TYPE_AUDIO, 00181 .codec_id = CODEC_ID_AAC, 00182 .parse_sdp_a_line = latm_parse_sdp_line, 00183 .alloc = latm_new_context, 00184 .free = latm_free_context, 00185 .parse_packet = latm_parse_packet 00186 };