diff options
Diffstat (limited to 'libavformat/sdp.c')
| -rw-r--r-- | libavformat/sdp.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/libavformat/sdp.c b/libavformat/sdp.c index b996bf65f5..92690f58a3 100644 --- a/libavformat/sdp.c +++ b/libavformat/sdp.c @@ -23,7 +23,9 @@ #include "libavutil/base64.h" #include "libavutil/dict.h" #include "libavutil/parseutils.h" +#include "libavutil/opt.h" #include "libavcodec/xiph.h" +#include "libavcodec/mpeg4audio.h" #include "avformat.h" #include "internal.h" #include "avc.h" @@ -300,6 +302,71 @@ xiph_fail: return NULL; } +static int latm_context2profilelevel(AVCodecContext *c) +{ + /* MP4A-LATM + * The RTP payload format specification is described in RFC 3016 + * The encoding specifications are provided in ISO/IEC 14496-3 */ + + int profile_level = 0x2B; + + /* TODO: AAC Profile only supports AAC LC Object Type. + * Different Object Types should implement different Profile Levels */ + + if (c->sample_rate <= 24000) { + if (c->channels <= 2) + profile_level = 0x28; // AAC Profile, Level 1 + } else if (c->sample_rate <= 48000) { + if (c->channels <= 2) { + profile_level = 0x29; // AAC Profile, Level 2 + } else if (c->channels <= 5) { + profile_level = 0x2A; // AAC Profile, Level 4 + } + } else if (c->sample_rate <= 96000) { + if (c->channels <= 5) { + profile_level = 0x2B; // AAC Profile, Level 5 + } + } + + return profile_level; +} + +static char *latm_context2config(AVCodecContext *c) +{ + /* MP4A-LATM + * The RTP payload format specification is described in RFC 3016 + * The encoding specifications are provided in ISO/IEC 14496-3 */ + + uint8_t config_byte[6]; + int rate_index; + char *config; + + for (rate_index = 0; rate_index < 16; rate_index++) + if (ff_mpeg4audio_sample_rates[rate_index] == c->sample_rate) + break; + if (rate_index == 16) { + av_log(c, AV_LOG_ERROR, "Unsupported sample rate\n"); + return NULL; + } + + config_byte[0] = 0x40; + config_byte[1] = 0; + config_byte[2] = 0x20 | rate_index; + config_byte[3] = c->channels << 4; + config_byte[4] = 0x3f; + config_byte[5] = 0xc0; + + config = av_malloc(6*2+1); + if (!config) { + av_log(c, AV_LOG_ERROR, "Cannot allocate memory for the config info.\n"); + return NULL; + } + ff_data_to_hex(config, config_byte, 6, 1); + config[12] = 0; + + return config; +} + static char *sdp_write_media_attributes(char *buff, int size, AVCodecContext *c, int payload_type, AVFormatContext *fmt) { char *config = NULL; @@ -335,6 +402,16 @@ static char *sdp_write_media_attributes(char *buff, int size, AVCodecContext *c, payload_type, config ? config : ""); break; case CODEC_ID_AAC: + if (fmt && fmt->oformat->priv_class && + av_opt_flag_is_set(fmt->priv_data, "rtpflags", "latm")) { + config = latm_context2config(c); + if (!config) + return NULL; + av_strlcatf(buff, size, "a=rtpmap:%d MP4A-LATM/%d/%d\r\n" + "a=fmtp:%d profile-level-id=%d;cpresent=0;config=%s\r\n", + payload_type, c->sample_rate, c->channels, + payload_type, latm_context2profilelevel(c), config); + } else { if (c->extradata_size) { config = extradata2config(c); } else { @@ -353,6 +430,7 @@ static char *sdp_write_media_attributes(char *buff, int size, AVCodecContext *c, "indexdeltalength=3%s\r\n", payload_type, c->sample_rate, c->channels, payload_type, config); + } break; case CODEC_ID_PCM_S16BE: if (payload_type >= RTP_PT_PRIVATE) |