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ffmpeg/libavformat/gxf.c

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/*
* GXF demuxer.
* Copyright (c) 2006 Reimar Doeffinger.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/common.h"
#include "avformat.h"
#include "gxf.h"
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
* \param type detected packet type is stored here
* \param length detected packet length, excluding header is stored here
* \return 0 if header not found or contains invalid data, 1 otherwise
*/
static int parse_packet_header(ByteIOContext *pb, pkt_type_t *type, int *length) {
if (get_be32(pb))
return 0;
if (get_byte(pb) != 1)
return 0;
*type = get_byte(pb);
*length = get_be32(pb);
if ((*length >> 24) || *length < 16)
return 0;
*length -= 16;
if (get_be32(pb))
return 0;
if (get_byte(pb) != 0xe1)
return 0;
if (get_byte(pb) != 0xe2)
return 0;
return 1;
}
/**
* \brief check if file starts with a PKT_MAP header
*/
static int gxf_probe(AVProbeData *p) {
static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
!memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
return AVPROBE_SCORE_MAX;
return 0;
}
/**
* \brief gets the stream index for the track with the specified id, creates new
* stream if not found
* \param stream id of stream to find / add
* \param format stream format identifier
*/
static int get_sindex(AVFormatContext *s, int id, int format) {
int i;
AVStream *st = NULL;
for (i = 0; i < s->nb_streams; i++) {
if (s->streams[i]->id == id)
return i;
}
st = av_new_stream(s, id);
switch (format) {
case 3:
case 4:
st->codec->codec_type = CODEC_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_MJPEG;
break;
case 13:
case 15:
st->codec->codec_type = CODEC_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_DVVIDEO;
break;
case 14:
case 16:
st->codec->codec_type = CODEC_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_DVVIDEO;
break;
case 11:
case 12:
case 20:
st->codec->codec_type = CODEC_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_MPEG2VIDEO;
st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
break;
case 22:
case 23:
st->codec->codec_type = CODEC_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_MPEG1VIDEO;
st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
break;
case 9:
st->codec->codec_type = CODEC_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_PCM_S24LE;
st->codec->channels = 1;
st->codec->sample_rate = 48000;
st->codec->bit_rate = 3 * 1 * 48000 * 8;
st->codec->block_align = 3 * 1;
st->codec->bits_per_sample = 24;
break;
case 10:
st->codec->codec_type = CODEC_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_PCM_S16LE;
st->codec->channels = 1;
st->codec->sample_rate = 48000;
st->codec->bit_rate = 2 * 1 * 48000 * 8;
st->codec->block_align = 2 * 1;
st->codec->bits_per_sample = 16;
break;
case 17:
st->codec->codec_type = CODEC_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_AC3;
st->codec->channels = 2;
st->codec->sample_rate = 48000;
break;
// timecode tracks:
case 7:
case 8:
case 24:
st->codec->codec_type = CODEC_TYPE_DATA;
st->codec->codec_id = CODEC_ID_NONE;
break;
default:
st->codec->codec_type = CODEC_TYPE_UNKNOWN;
st->codec->codec_id = CODEC_ID_NONE;
break;
}
return s->nb_streams - 1;
}
/**
* \brief filters out interesting tags from material 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_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;
}
map_len -= 2;
if (get_byte(pb) != 0x0e0 || get_byte(pb) != 0xff) {
av_log(s, AV_LOG_ERROR, "GXF: unknown version or invalid map preamble\n");
return 0;
}
map_len -= 2;
len = get_be16(pb); // length of material data section
if (len > map_len) {
av_log(s, AV_LOG_ERROR, "GXF: material data longer than map data\n");
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
if (len > map_len) {
av_log(s, AV_LOG_ERROR, "GXF: track description longer than map data\n");
return 0;
}
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);
continue;
}
track_type &= 0x7f;
if ((track_id & 0xc0) != 0xc0) {
av_log(s, AV_LOG_ERROR, "GXF: invalid track id %x\n", track_id);
continue;
}
track_id &= 0x3f;
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 >= 0x39) {
AVRational fps;
len -= 0x39;
url_fskip(pb, 5); // preamble
url_fskip(pb, 0x30); // payload description
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);
if (!main_timebase.num || !main_timebase.den)
main_timebase = (AVRational){1, 50}; // set some arbitrary fallback
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
av_set_pts_info(st, 32, main_timebase.num, main_timebase.den);
}
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 = get_be32(pb);
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;
}
if (pkt_len < 16) {
av_log(s, AV_LOG_ERROR, "GXF: invalid media packet length\n");
continue;
}
pkt_len -= 16;
track_type = get_byte(pb);
track_id = get_byte(pb);
field_nr = get_be32(pb);
get_be32(pb); // field information
get_be32(pb); // "timeline" field number
get_byte(pb); // flags
get_byte(pb); // reserved
// NOTE: there is also data length information in the
// field information, it might be better to take this into account
// as well.
ret = av_get_packet(pb, pkt, pkt_len);
pkt->stream_index = get_sindex(s, track_id, track_type);
pkt->dts = field_nr;
return ret;
}
return AVERROR(EIO);
}
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 (FFABS(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",
0,
gxf_probe,
gxf_header,
gxf_packet,
NULL,
gxf_seek,
gxf_read_timestamp,
};
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