Author: ods15 Date: Sat Nov 18 11:17:08 2006 New Revision: 230 Modified: trunk/libnut/demuxer.c Log: Make find_main_headers() search at 2^n positions and from EOF Make first syncpoint be read right at the begginning Modified: trunk/libnut/demuxer.c ============================================================================== --- trunk/libnut/demuxer.c (original) +++ trunk/libnut/demuxer.c Sat Nov 18 11:17:08 2006 @@ -553,7 +553,7 @@ CHECK(add_syncpoint(nut, s, pts, eor, &i)); nut->syncpoints.s[i - 1].seen_next = 1; } - } else if (!nut->syncpoints.len || nut->dopts.cache_syncpoints) { + } else if (nut->dopts.cache_syncpoints) { // we're seeking, we need syncpoint cache int i; CHECK(add_syncpoint(nut, s, NULL, NULL, &i)); if (!after_seek) nut->syncpoints.s[i - 1].seen_next = 1; @@ -758,24 +758,54 @@ static int find_main_headers(nut_context_t * nut) { int err = 0; uint64_t tmp; - off_t start = bctello(nut->i); - if (start < strlen(ID_STRING) + 1) { - int n = strlen(ID_STRING) + 1 - start; - ERROR(ready_read_buf(nut->i, n) < n, buf_eof(nut->i)); - if (memcmp(get_buf(nut->i, start), ID_STRING + start, n)) nut->i->buf_ptr = nut->i->buf; // rewind - else fprintf(stderr, "NUT file_id checks out\n"); - } + int read_data = 512*1024; + + // don't waste cpu by running this check every damn time for EAGAIN + // Except for the first time, to not waste memory + if (!nut->seek_status && ready_read_buf(nut->i, read_data) < read_data && buf_eof(nut->i) == NUT_ERR_EAGAIN) + return NUT_ERR_EAGAIN; CHECK(get_bytes(nut->i, 7, &tmp)); - ERROR(ready_read_buf(nut->i, 4096) < 4096, buf_eof(nut->i)); - while (bctello(nut->i) < 4096) { + read_data -= 7; + while (read_data--) { + ERROR(ready_read_buf(nut->i, 30) < 1, buf_eof(nut->i)); tmp = (tmp << 8) | *(nut->i->buf_ptr++); if (tmp == MAIN_STARTCODE) break; + // give up if we reach a syncpoint, unless we're searching the file end + if (tmp == SYNCPOINT_STARTCODE && nut->seek_status != 18) break; } - ERROR(tmp != MAIN_STARTCODE, NUT_ERR_NO_HEADERS); - nut->i->buf_ptr -= 8; - nut->last_headers = bctello(nut->i); - flush_buf(nut->i); + if (tmp == MAIN_STARTCODE) { + off_t pos = bctello(nut->i) - 8; + // load all headers into memory so they can be cleanly decoded without EAGAIN issues + // also check validity of the headers we just found + do { + if ((err = get_header(nut->i, NULL)) == NUT_ERR_EAGAIN) goto err_out; + if (err) { tmp = err = 0; break; } // bad + + if ((err = get_bytes(nut->i, 8, &tmp)) == NUT_ERR_EAGAIN) goto err_out; + assert(!err || err == NUT_ERR_EOF); // the only possibilities + // EOF is a legal error here - when reading the last headers in file + if (err == NUT_ERR_EOF) { err = 0; tmp = SYNCPOINT_STARTCODE; } + } while (tmp != SYNCPOINT_STARTCODE); + if (tmp == SYNCPOINT_STARTCODE) { // success! + nut->last_headers = pos; + nut->i->buf_ptr = get_buf(nut->i, nut->last_headers); + flush_buf(nut->i); + return 0; + } + } + + // failure + if (!nut->i->isc.seek) return NUT_ERR_NO_HEADERS; + if (!nut->seek_status) { + nut->seek_status = 18; // start search at 512kb + // but first, let's check EOF + seek_buf(nut->i, -512*1024, SEEK_END); + return find_main_headers(nut); + } + seek_buf(nut->i, 1 << ++nut->seek_status, SEEK_SET); + // evantually we'll hit EOF and give up + return find_main_headers(nut); err_out: return err; } @@ -841,8 +871,6 @@ int nut_read_next_packet(nut_context_t * nut, nut_packet_t * pd) { int err = 0; - ERROR(!nut->last_headers, NUT_ERR_NO_HEADERS); // paranoia, old API - if (nut->seek_status) { // in error mode! syncpoint_t s; CHECK(find_syncpoint(nut, 0, &s, 0)); @@ -874,15 +902,10 @@ int nut_read_headers(nut_context_t * nut, nut_stream_header_t * s [], nut_info_packet_t * info []) { int i, err = 0; uint64_t tmp; + syncpoint_t sp; if (!nut->sc) { // we already have headers, we were called just for index if (!nut->last_headers) CHECK(find_main_headers(nut)); - // load all headers into memory so they can be cleanly decoded without EAGAIN issues - // FIXME deal with errors and such - CHECK(skip_reserved_headers(nut, SYNCPOINT_STARTCODE)); - - // rewind to where the headers were found - nut->i->buf_ptr = get_buf(nut->i, nut->last_headers); CHECK(get_headers(nut, !!info)); if (nut->dopts.read_index) { // check for index right after main headers @@ -919,9 +942,17 @@ nut->before_seek = 0; } - if ((err = skip_reserved_headers(nut, SYNCPOINT_STARTCODE)) == NUT_ERR_EAGAIN) goto err_out; - nut->seek_status = !!err; // enter error mode if we're not at a syncpoint - err = 0; + // last step - find the first syncpoint in file + if (nut->last_headers > 1024 && !nut->seek_status) { + // the headers weren't found in begginning of file + assert(nut->i->isc.seek); + seek_buf(nut->i, 0, SEEK_SET); + nut->seek_status = 1; + } + CHECK(find_syncpoint(nut, 0, &sp, 0)); + CHECK(add_syncpoint(nut, sp, NULL, NULL, NULL)); + nut->i->buf_ptr = get_buf(nut->i, sp.pos); // rewind to the syncpoint, this is where playback starts... + nut->seek_status = 0; SAFE_CALLOC(nut->alloc, *s, sizeof(nut_stream_header_t), nut->stream_count + 1); for (i = 0; i < nut->stream_count; i++) (*s)[i] = nut->sc[i].sh; @@ -958,14 +989,7 @@ syncpoint_list_t * sl = &nut->syncpoints; syncpoint_t s; - if (!sl->len) { // not even a single syncpoint, find first one. - // the first syncpoint put in the cache is always always the BEGIN syncpoint - if (!nut->seek_status) seek_buf(nut->i, 0, SEEK_SET); - nut->seek_status = 1; - CHECK(find_syncpoint(nut, 0, &s, 0)); - CHECK(add_syncpoint(nut, s, NULL, NULL, NULL)); - nut->seek_status = 0; - } + assert(sl->len); // it is impossible for the first syncpoint to not have been read // find last syncpoint if it's not already found if (!sl->s[sl->len-1].seen_next) { @@ -1008,8 +1032,7 @@ goto err_out; } if (i == 0) { // there isn't any syncpoint smaller than requested - if (sl->s[0].pts) seek_buf(nut->i, sl->s[0].pos, SEEK_SET); - else seek_buf(nut->i, nut->last_headers, SEEK_SET); // seeking to "begginning of file", the headers + seek_buf(nut->i, sl->s[0].pos, SEEK_SET); // seek to first syncpoint clear_dts_cache(nut); nut->last_syncpoint = 0; goto err_out;