[Ffmpeg-cvslog] r5880 - trunk/libavformat/gxf.c
reimar
subversion
Tue Aug 1 12:19:28 CEST 2006
Author: reimar
Date: Tue Aug 1 12:19:25 2006
New Revision: 5880
Modified:
trunk/libavformat/gxf.c
Log:
Support for seeking, both with and without index and correct timestamps
Modified: trunk/libavformat/gxf.c
==============================================================================
--- trunk/libavformat/gxf.c (original)
+++ trunk/libavformat/gxf.c Tue Aug 1 12:19:25 2006
@@ -17,6 +17,7 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
+#include "common.h"
typedef enum {
PKT_MAP = 0xbc,
@@ -26,6 +27,32 @@
PKT_UMF = 0xfd
} pkt_type_t;
+typedef enum {
+ MAT_NAME = 0x40,
+ MAT_FIRST_FIELD = 0x41,
+ MAT_LAST_FIELD = 0x42,
+ MAT_MARK_IN = 0x43,
+ MAT_MARK_OUT = 0x44,
+ MAT_SIZE = 0x45
+} mat_tag_t;
+
+typedef enum {
+ TRACK_NAME = 0x4c,
+ TRACK_AUX = 0x4d,
+ TRACK_VER = 0x4e,
+ TRACK_MPG_AUX = 0x4f,
+ TRACK_FPS = 0x50,
+ TRACK_LINES = 0x51,
+ TRACK_FPF = 0x52
+} track_tag_t;
+
+typedef struct {
+ int64_t first_field;
+ int64_t last_field;
+ AVRational frames_per_second;
+ int32_t fields_per_frame;
+} st_info_t;
+
/**
* \brief parses a packet header, extracting type and length
* \param pb ByteIOContext to read header from
@@ -147,11 +174,116 @@
return s->nb_streams - 1;
}
+/**
+ * \brief filters out interesting tags from material information.
+ * \param len lenght of tag section, will be adjusted to contain remaining bytes
+ * \param si struct to store collected information into
+ */
+static void gxf_material_tags(ByteIOContext *pb, int *len, st_info_t *si) {
+ si->first_field = AV_NOPTS_VALUE;
+ si->last_field = AV_NOPTS_VALUE;
+ while (*len >= 2) {
+ mat_tag_t tag = get_byte(pb);
+ int tlen = get_byte(pb);
+ *len -= 2;
+ if (tlen > *len)
+ return;
+ *len -= tlen;
+ if (tlen == 4) {
+ uint32_t value = get_be32(pb);
+ if (tag == MAT_FIRST_FIELD)
+ si->first_field = value;
+ else if (tag == MAT_LAST_FIELD)
+ si->last_field = value;
+ } else
+ url_fskip(pb, tlen);
+ }
+}
+
+/**
+ * \brief convert fps tag value to AVRational fps
+ * \param fps fps value from tag
+ * \return fps as AVRational, or 0 / 0 if unknown
+ */
+static AVRational fps_tag2avr(int32_t fps) {
+ extern const AVRational ff_frame_rate_tab[];
+ if (fps < 1 || fps > 9) fps = 9;
+ return ff_frame_rate_tab[9 - fps]; // values have opposite order
+}
+
+/**
+ * \brief convert UMF attributes flags to AVRational fps
+ * \param fps fps value from flags
+ * \return fps as AVRational, or 0 / 0 if unknown
+ */
+static AVRational fps_umf2avr(uint32_t flags) {
+ static const AVRational map[] = {{50, 1}, {60000, 1001}, {24, 1},
+ {25, 1}, {30000, 1001}};
+ int idx = av_log2((flags & 0x7c0) >> 6);
+ return map[idx];
+}
+
+/**
+ * \brief filters out interesting tags from track information.
+ * \param len length of tag section, will be adjusted to contain remaining bytes
+ * \param si struct to store collected information into
+ */
+static void gxf_track_tags(ByteIOContext *pb, int *len, st_info_t *si) {
+ si->frames_per_second = (AVRational){0, 0};
+ si->fields_per_frame = 0;
+ while (*len >= 2) {
+ track_tag_t tag = get_byte(pb);
+ int tlen = get_byte(pb);
+ *len -= 2;
+ if (tlen > *len)
+ return;
+ *len -= tlen;
+ if (tlen == 4) {
+ uint32_t value = get_be32(pb);
+ if (tag == TRACK_FPS)
+ si->frames_per_second = fps_tag2avr(value);
+ else if (tag == TRACK_FPF && (value == 1 || value == 2))
+ si->fields_per_frame = value;
+ } else
+ url_fskip(pb, tlen);
+ }
+}
+
+/**
+ * \brief read index from FLT packet into stream 0 av_index
+ */
+static void gxf_read_index(AVFormatContext *s, int pkt_len) {
+ ByteIOContext *pb = &s->pb;
+ AVStream *st = s->streams[0];
+ uint32_t fields_per_map = get_le32(pb);
+ uint32_t map_cnt = get_le32(pb);
+ int i;
+ pkt_len -= 8;
+ if (map_cnt > 1000) {
+ av_log(s, AV_LOG_ERROR, "GXF: too many index entries %u (%x)\n", map_cnt, map_cnt);
+ map_cnt = 1000;
+ }
+ if (pkt_len < 4 * map_cnt) {
+ av_log(s, AV_LOG_ERROR, "GXF: invalid index length\n");
+ url_fskip(pb, pkt_len);
+ return;
+ }
+ pkt_len -= 4 * map_cnt;
+ av_add_index_entry(st, 0, 0, 0, 0, 0);
+ for (i = 0; i < map_cnt; i++)
+ av_add_index_entry(st, (uint64_t)get_le32(pb) * 1024,
+ i * (uint64_t)fields_per_map + 1, 0, 0, 0);
+ url_fskip(pb, pkt_len);
+}
+
static int gxf_header(AVFormatContext *s, AVFormatParameters *ap) {
ByteIOContext *pb = &s->pb;
pkt_type_t pkt_type;
int map_len;
int len;
+ AVRational main_timebase = {0, 0};
+ st_info_t si;
+ int i;
if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
av_log(s, AV_LOG_ERROR, "GXF: map packet not found\n");
return 0;
@@ -168,6 +300,7 @@
return 0;
}
map_len -= len;
+ gxf_material_tags(pb, &len, &si);
url_fskip(pb, len);
map_len -= 2;
len = get_be16(pb); // length of track description
@@ -178,11 +311,14 @@
map_len -= len;
while (len > 0) {
int track_type, track_id, track_len;
+ AVStream *st;
+ int idx;
len -= 4;
track_type = get_byte(pb);
track_id = get_byte(pb);
track_len = get_be16(pb);
len -= track_len;
+ gxf_track_tags(pb, &track_len, &si);
url_fskip(pb, track_len);
if (!(track_type & 0x80)) {
av_log(s, AV_LOG_ERROR, "GXF: invalid track type %x\n", track_type);
@@ -194,26 +330,125 @@
continue;
}
track_id &= 0x3f;
- get_sindex(s, track_id, track_type);
+ idx = get_sindex(s, track_id, track_type);
+ if (idx < 0) continue;
+ st = s->streams[idx];
+ if (!main_timebase.num || !main_timebase.den) {
+ main_timebase.num = si.frames_per_second.den;
+ main_timebase.den = si.frames_per_second.num * si.fields_per_frame;
+ }
+ st->start_time = si.first_field;
+ if (si.first_field != AV_NOPTS_VALUE && si.last_field != AV_NOPTS_VALUE)
+ st->duration = si.last_field - si.first_field;
}
if (len < 0)
av_log(s, AV_LOG_ERROR, "GXF: invalid track description length specified\n");
if (map_len)
url_fskip(pb, map_len);
+ if (!parse_packet_header(pb, &pkt_type, &len)) {
+ av_log(s, AV_LOG_ERROR, "GXF: sync lost in header\n");
+ return -1;
+ }
+ if (pkt_type == PKT_FLT) {
+ gxf_read_index(s, len);
+ if (!parse_packet_header(pb, &pkt_type, &len)) {
+ av_log(s, AV_LOG_ERROR, "GXF: sync lost in header\n");
+ return -1;
+ }
+ }
+ if (pkt_type == PKT_UMF) {
+ if (len >= 9) {
+ AVRational fps;
+ len -= 9;
+ url_fskip(pb, 5);
+ fps = fps_umf2avr(get_le32(pb));
+ if (!main_timebase.num || !main_timebase.den) {
+ // this may not always be correct, but simply the best we can get
+ main_timebase.num = fps.den;
+ main_timebase.den = fps.num;
+ }
+ } else
+ av_log(s, AV_LOG_INFO, "GXF: UMF packet too short\n");
+ } else
+ av_log(s, AV_LOG_INFO, "GXF: UMF packet missing\n");
+ url_fskip(pb, len);
+ for (i = 0; i < s->nb_streams; i++) {
+ AVStream *st = s->streams[i];
+ if (main_timebase.num && main_timebase.den)
+ st->time_base = main_timebase;
+ else {
+ st->start_time = st->duration = AV_NOPTS_VALUE;
+ }
+ }
return 0;
}
+#define READ_ONE() \
+ { \
+ if (!max_interval-- || url_feof(pb)) \
+ goto out; \
+ tmp = tmp << 8 | get_byte(pb); \
+ }
+
+/**
+ * \brief resync the stream on the next media packet with specified properties
+ * \param max_interval how many bytes to search for matching packet at most
+ * \param track track id the media packet must belong to, -1 for any
+ * \param timestamp minimum timestamp (== field number) the packet must have, -1 for any
+ * \return timestamp of packet found
+ */
+static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {
+ uint32_t tmp;
+ uint64_t last_pos;
+ uint64_t last_found_pos = 0;
+ int cur_track;
+ int64_t cur_timestamp = AV_NOPTS_VALUE;
+ int len;
+ ByteIOContext *pb = &s->pb;
+ pkt_type_t type;
+ tmp = 0xff;
+start:
+ while (tmp)
+ READ_ONE();
+ READ_ONE();
+ if (tmp != 1)
+ goto start;
+ last_pos = url_ftell(pb);
+ url_fseek(pb, -5, SEEK_CUR);
+ if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {
+ url_fseek(pb, last_pos, SEEK_SET);
+ goto start;
+ }
+ get_byte(pb);
+ cur_track = get_byte(pb);
+ cur_timestamp = get_be32(pb);
+ last_found_pos = url_ftell(pb) - 16 - 6;
+ if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {
+ url_fseek(pb, last_pos, SEEK_SET);
+ goto start;
+ }
+out:
+ if (last_found_pos)
+ url_fseek(pb, last_found_pos, SEEK_SET);
+ return cur_timestamp;
+}
+
static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
ByteIOContext *pb = &s->pb;
pkt_type_t pkt_type;
int pkt_len;
while (!url_feof(pb)) {
int track_type, track_id, ret;
+ int field_nr;
if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
if (!url_feof(pb))
av_log(s, AV_LOG_ERROR, "GXF: sync lost\n");
return -1;
}
+ if (pkt_type == PKT_FLT) {
+ gxf_read_index(s, pkt_len);
+ continue;
+ }
if (pkt_type != PKT_MEDIA) {
url_fskip(pb, pkt_len);
continue;
@@ -225,7 +460,7 @@
pkt_len -= 16;
track_type = get_byte(pb);
track_id = get_byte(pb);
- get_be32(pb); // field number
+ field_nr = get_be32(pb);
get_be32(pb); // field information
get_be32(pb); // "timeline" field number
get_byte(pb); // flags
@@ -235,11 +470,45 @@
// as well.
ret = av_get_packet(pb, pkt, pkt_len);
pkt->stream_index = get_sindex(s, track_id, track_type);
+ pkt->pts = field_nr;
return ret;
}
return AVERROR_IO;
}
+static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
+ uint64_t pos;
+ uint64_t maxlen = 100 * 1024 * 1024;
+ AVStream *st = s->streams[0];
+ int64_t start_time = s->streams[stream_index]->start_time;
+ int64_t found;
+ int idx;
+ if (timestamp < start_time) timestamp = start_time;
+ idx = av_index_search_timestamp(st, timestamp - start_time,
+ AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);
+ if (idx < 0)
+ return -1;
+ pos = st->index_entries[idx].pos;
+ if (idx < st->nb_index_entries - 2)
+ maxlen = st->index_entries[idx + 2].pos - pos;
+ maxlen = FFMAX(maxlen, 200 * 1024);
+ url_fseek(&s->pb, pos, SEEK_SET);
+ found = gxf_resync_media(s, maxlen, -1, timestamp);
+ if (ABS(found - timestamp) > 4)
+ return -1;
+ return 0;
+}
+
+static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,
+ int64_t *pos, int64_t pos_limit) {
+ ByteIOContext *pb = &s->pb;
+ int64_t res;
+ url_fseek(pb, *pos, SEEK_SET);
+ res = gxf_resync_media(s, pos_limit - *pos, -1, -1);
+ *pos = url_ftell(pb);
+ return res;
+}
+
AVInputFormat gxf_demuxer = {
"gxf",
"GXF format",
@@ -248,5 +517,6 @@
gxf_header,
gxf_packet,
NULL,
- NULL,
+ gxf_seek,
+ gxf_read_timestamp,
};
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