+static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, AVStream *vstream, int64_t max_pos) {
+ FLVContext *flv = s->priv_data;
+ unsigned int arraylen = 0, timeslen = 0, fileposlen = 0, i;
+ double num_val;
+ char str_val[256];
+ int64_t *times = NULL;
+ int64_t *filepositions = NULL;
+ int ret = AVERROR(ENOSYS);
+ int64_t initial_pos = avio_tell(ioc);
+
+ if (s->flags & AVFMT_FLAG_IGNIDX)
+ return 0;
+
+ while (avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
+ int64_t* current_array;
+
+ // Expect array object in context
+ if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)
+ break;
+
+ arraylen = avio_rb32(ioc);
+ if (arraylen >> 28)
+ break;
+
+ /*
+ * Expect only 'times' or 'filepositions' sub-arrays in other case refuse to use such metadata
+ * for indexing
+ */
+ if (!strcmp(KEYFRAMES_TIMESTAMP_TAG, str_val) && !times) {
+ if (!(times = av_mallocz(sizeof(*times) * arraylen))) {
+ ret = AVERROR(ENOMEM);
+ goto finish;
+ }
+ timeslen = arraylen;
+ current_array = times;
+ } else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) && !filepositions) {
+ if (!(filepositions = av_mallocz(sizeof(*filepositions) * arraylen))) {
+ ret = AVERROR(ENOMEM);
+ goto finish;
+ }
+ fileposlen = arraylen;
+ current_array = filepositions;
+ } else // unexpected metatag inside keyframes, will not use such metadata for indexing
+ break;
+
+ for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
+ if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)
+ goto finish;
+ num_val = av_int2double(avio_rb64(ioc));
+ current_array[i] = num_val;
+ }
+ if (times && filepositions) {
+ // All done, exiting at a position allowing amf_parse_object
+ // to finish parsing the object
+ ret = 0;
+ break;
+ }
+ }
+
+ if (!ret && timeslen == fileposlen) {
+ for (i = 0; i < fileposlen; i++) {
+ av_add_index_entry(vstream, filepositions[i], times[i]*1000,
+ 0, 0, AVINDEX_KEYFRAME);
+ if (i < 2) {
+ flv->validate_index[i].pos = filepositions[i];
+ flv->validate_index[i].dts = times[i] * 1000;
+ flv->validate_count = i + 1;
+ }
+ }
+ } else
+ av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");
+
+finish:
+ av_freep(×);
+ av_freep(&filepositions);
+ // If we got unexpected data, but successfully reset back to
+ // the start pos, the caller can continue parsing
+ if (ret < 0 && avio_seek(ioc, initial_pos, SEEK_SET) > 0)
+ return 0;
+ return ret;
+}
+