+
+int ff_mp4_read_descr_len(AVIOContext *pb)
+{
+ int len = 0;
+ int count = 4;
+ while (count--) {
+ int c = avio_r8(pb);
+ len = (len << 7) | (c & 0x7f);
+ if (!(c & 0x80))
+ break;
+ }
+ return len;
+}
+
+int ff_mp4_read_descr(AVFormatContext *fc, AVIOContext *pb, int *tag)
+{
+ int len;
+ *tag = avio_r8(pb);
+ len = ff_mp4_read_descr_len(pb);
+ av_dlog(fc, "MPEG4 description: tag=0x%02x len=%d\n", *tag, len);
+ return len;
+}
+
+void ff_mp4_parse_es_descr(AVIOContext *pb, int *es_id)
+{
+ int flags;
+ if (es_id) *es_id = avio_rb16(pb);
+ else avio_rb16(pb);
+ flags = avio_r8(pb);
+ if (flags & 0x80) //streamDependenceFlag
+ avio_rb16(pb);
+ if (flags & 0x40) { //URL_Flag
+ int len = avio_r8(pb);
+ avio_skip(pb, len);
+ }
+ if (flags & 0x20) //OCRstreamFlag
+ avio_rb16(pb);
+}
+
+static const AVCodecTag mp4_audio_types[] = {
+ { CODEC_ID_MP3ON4, AOT_PS }, /* old mp3on4 draft */
+ { CODEC_ID_MP3ON4, AOT_L1 }, /* layer 1 */
+ { CODEC_ID_MP3ON4, AOT_L2 }, /* layer 2 */
+ { CODEC_ID_MP3ON4, AOT_L3 }, /* layer 3 */
+ { CODEC_ID_MP4ALS, AOT_ALS }, /* MPEG-4 ALS */
+ { CODEC_ID_NONE, AOT_NULL },
+};
+
+int ff_mp4_read_dec_config_descr(AVFormatContext *fc, AVStream *st, AVIOContext *pb)
+{
+ int len, tag;
+ int object_type_id = avio_r8(pb);
+ avio_r8(pb); /* stream type */
+ avio_rb24(pb); /* buffer size db */
+ avio_rb32(pb); /* max bitrate */
+ avio_rb32(pb); /* avg bitrate */
+
+ st->codec->codec_id= ff_codec_get_id(ff_mp4_obj_type, object_type_id);
+ av_dlog(fc, "esds object type id 0x%02x\n", object_type_id);
+ len = ff_mp4_read_descr(fc, pb, &tag);
+ if (tag == MP4DecSpecificDescrTag) {
+ av_dlog(fc, "Specific MPEG4 header len=%d\n", len);
+ if (!len || (uint64_t)len > (1<<30))
+ return -1;
+ av_free(st->codec->extradata);
+ st->codec->extradata = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
+ if (!st->codec->extradata)
+ return AVERROR(ENOMEM);
+ avio_read(pb, st->codec->extradata, len);
+ st->codec->extradata_size = len;
+ if (st->codec->codec_id == CODEC_ID_AAC) {
+ MPEG4AudioConfig cfg;
+ ff_mpeg4audio_get_config(&cfg, st->codec->extradata,
+ st->codec->extradata_size);
+ st->codec->channels = cfg.channels;
+ if (cfg.object_type == 29 && cfg.sampling_index < 3) // old mp3on4
+ st->codec->sample_rate = ff_mpa_freq_tab[cfg.sampling_index];
+ else if (cfg.ext_sample_rate)
+ st->codec->sample_rate = cfg.ext_sample_rate;
+ else
+ st->codec->sample_rate = cfg.sample_rate;
+ av_dlog(fc, "mp4a config channels %d obj %d ext obj %d "
+ "sample rate %d ext sample rate %d\n", st->codec->channels,
+ cfg.object_type, cfg.ext_object_type,
+ cfg.sample_rate, cfg.ext_sample_rate);
+ if (!(st->codec->codec_id = ff_codec_get_id(mp4_audio_types,
+ cfg.object_type)))
+ st->codec->codec_id = CODEC_ID_AAC;
+ }
+ }
+ return 0;
+}