FFmpeg/libavformat/gxf.c
Anton Khirnov 9200514ad8 lavf: replace AVStream.codec with AVStream.codecpar
Currently, AVStream contains an embedded AVCodecContext instance, which
is used by demuxers to export stream parameters to the caller and by
muxers to receive stream parameters from the caller. It is also used
internally as the codec context that is passed to parsers.

In addition, it is also widely used by the callers as the decoding (when
demuxer) or encoding (when muxing) context, though this has been
officially discouraged since Libav 11.

There are multiple important problems with this approach:
    - the fields in AVCodecContext are in general one of
        * stream parameters
        * codec options
        * codec state
      However, it's not clear which ones are which. It is consequently
      unclear which fields are a demuxer allowed to set or a muxer allowed to
      read. This leads to erratic behaviour depending on whether decoding or
      encoding is being performed or not (and whether it uses the AVStream
      embedded codec context).
    - various synchronization issues arising from the fact that the same
      context is used by several different APIs (muxers/demuxers,
      parsers, bitstream filters and encoders/decoders) simultaneously, with
      there being no clear rules for who can modify what and the different
      processes being typically delayed with respect to each other.
    - avformat_find_stream_info() making it necessary to support opening
      and closing a single codec context multiple times, thus
      complicating the semantics of freeing various allocated objects in the
      codec context.

Those problems are resolved by replacing the AVStream embedded codec
context with a newly added AVCodecParameters instance, which stores only
the stream parameters exported by the demuxers or read by the muxers.
2016-02-23 17:01:58 +01:00

556 lines
18 KiB
C

/*
* GXF demuxer.
* Copyright (c) 2006 Reimar Doeffinger
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <inttypes.h>
#include "libavutil/channel_layout.h"
#include "libavutil/common.h"
#include "avformat.h"
#include "internal.h"
#include "gxf.h"
#include "libavcodec/mpeg12data.h"
struct gxf_stream_info {
int64_t first_field;
int64_t last_field;
AVRational frames_per_second;
int32_t fields_per_frame;
};
/**
* @brief parses a packet header, extracting type and length
* @param pb AVIOContext 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(AVIOContext *pb, GXFPktType *type, int *length) {
if (avio_rb32(pb))
return 0;
if (avio_r8(pb) != 1)
return 0;
*type = avio_r8(pb);
*length = avio_rb32(pb);
if ((*length >> 24) || *length < 16)
return 0;
*length -= 16;
if (avio_rb32(pb))
return 0;
if (avio_r8(pb) != 0xe1)
return 0;
if (avio_r8(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 id 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;
i = ff_find_stream_index(s, id);
if (i >= 0)
return i;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->id = id;
switch (format) {
case 3:
case 4:
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_MJPEG;
break;
case 13:
case 15:
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_DVVIDEO;
break;
case 14:
case 16:
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_DVVIDEO;
break;
case 11:
case 12:
case 20:
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_MPEG2VIDEO;
st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
break;
case 22:
case 23:
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_MPEG1VIDEO;
st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
break;
case 9:
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_PCM_S24LE;
st->codecpar->channels = 1;
st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
st->codecpar->sample_rate = 48000;
st->codecpar->bit_rate = 3 * 1 * 48000 * 8;
st->codecpar->block_align = 3 * 1;
st->codecpar->bits_per_coded_sample = 24;
break;
case 10:
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
st->codecpar->channels = 1;
st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
st->codecpar->sample_rate = 48000;
st->codecpar->bit_rate = 2 * 1 * 48000 * 8;
st->codecpar->block_align = 2 * 1;
st->codecpar->bits_per_coded_sample = 16;
break;
case 17:
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_AC3;
st->codecpar->channels = 2;
st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
st->codecpar->sample_rate = 48000;
break;
// timecode tracks:
case 7:
case 8:
case 24:
st->codecpar->codec_type = AVMEDIA_TYPE_DATA;
st->codecpar->codec_id = AV_CODEC_ID_NONE;
break;
default:
st->codecpar->codec_type = AVMEDIA_TYPE_UNKNOWN;
st->codecpar->codec_id = AV_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(AVIOContext *pb, int *len, struct gxf_stream_info *si) {
si->first_field = AV_NOPTS_VALUE;
si->last_field = AV_NOPTS_VALUE;
while (*len >= 2) {
GXFMatTag tag = avio_r8(pb);
int tlen = avio_r8(pb);
*len -= 2;
if (tlen > *len)
return;
*len -= tlen;
if (tlen == 4) {
uint32_t value = avio_rb32(pb);
if (tag == MAT_FIRST_FIELD)
si->first_field = value;
else if (tag == MAT_LAST_FIELD)
si->last_field = value;
} else
avio_skip(pb, tlen);
}
}
static const AVRational frame_rate_tab[] = {
{ 60, 1},
{60000, 1001},
{ 50, 1},
{ 30, 1},
{30000, 1001},
{ 25, 1},
{ 24, 1},
{24000, 1001},
{ 0, 0},
};
/**
* @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) {
if (fps < 1 || fps > 9) fps = 9;
return frame_rate_tab[fps - 1];
}
/**
* @brief convert UMF attributes flags to AVRational fps
* @param flags UMF flags to convert
* @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(AVIOContext *pb, int *len, struct gxf_stream_info *si) {
si->frames_per_second = (AVRational){0, 0};
si->fields_per_frame = 0;
while (*len >= 2) {
GXFTrackTag tag = avio_r8(pb);
int tlen = avio_r8(pb);
*len -= 2;
if (tlen > *len)
return;
*len -= tlen;
if (tlen == 4) {
uint32_t value = avio_rb32(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
avio_skip(pb, tlen);
}
}
/**
* @brief read index from FLT packet into stream 0 av_index
*/
static void gxf_read_index(AVFormatContext *s, int pkt_len) {
AVIOContext *pb = s->pb;
AVStream *st = s->streams[0];
uint32_t fields_per_map = avio_rl32(pb);
uint32_t map_cnt = avio_rl32(pb);
int i;
pkt_len -= 8;
if (s->flags & AVFMT_FLAG_IGNIDX) {
avio_skip(pb, pkt_len);
return;
}
if (map_cnt > 1000) {
av_log(s, AV_LOG_ERROR,
"too many index entries %"PRIu32" (%"PRIx32")\n",
map_cnt, map_cnt);
map_cnt = 1000;
}
if (pkt_len < 4 * map_cnt) {
av_log(s, AV_LOG_ERROR, "invalid index length\n");
avio_skip(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)avio_rl32(pb) * 1024,
i * (uint64_t)fields_per_map + 1, 0, 0, 0);
avio_skip(pb, pkt_len);
}
static int gxf_header(AVFormatContext *s) {
AVIOContext *pb = s->pb;
GXFPktType pkt_type;
int map_len;
int len;
AVRational main_timebase = {0, 0};
struct gxf_stream_info *si = s->priv_data;
int i;
if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
av_log(s, AV_LOG_ERROR, "map packet not found\n");
return 0;
}
map_len -= 2;
if (avio_r8(pb) != 0x0e0 || avio_r8(pb) != 0xff) {
av_log(s, AV_LOG_ERROR, "unknown version or invalid map preamble\n");
return 0;
}
map_len -= 2;
len = avio_rb16(pb); // length of material data section
if (len > map_len) {
av_log(s, AV_LOG_ERROR, "material data longer than map data\n");
return 0;
}
map_len -= len;
gxf_material_tags(pb, &len, si);
avio_skip(pb, len);
map_len -= 2;
len = avio_rb16(pb); // length of track description
if (len > map_len) {
av_log(s, AV_LOG_ERROR, "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 = avio_r8(pb);
track_id = avio_r8(pb);
track_len = avio_rb16(pb);
len -= track_len;
gxf_track_tags(pb, &track_len, si);
avio_skip(pb, track_len);
if (!(track_type & 0x80)) {
av_log(s, AV_LOG_ERROR, "invalid track type %x\n", track_type);
continue;
}
track_type &= 0x7f;
if ((track_id & 0xc0) != 0xc0) {
av_log(s, AV_LOG_ERROR, "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 * 2;
}
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, "invalid track description length specified\n");
if (map_len)
avio_skip(pb, map_len);
if (!parse_packet_header(pb, &pkt_type, &len)) {
av_log(s, AV_LOG_ERROR, "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, "sync lost in header\n");
return -1;
}
}
if (pkt_type == PKT_UMF) {
if (len >= 0x39) {
AVRational fps;
len -= 0x39;
avio_skip(pb, 5); // preamble
avio_skip(pb, 0x30); // payload description
fps = fps_umf2avr(avio_rl32(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 * 2;
}
} else
av_log(s, AV_LOG_INFO, "UMF packet too short\n");
} else
av_log(s, AV_LOG_INFO, "UMF packet missing\n");
avio_skip(pb, len);
// set a fallback value, 60000/1001 is specified for audio-only files
// so use that regardless of why we do not know the video frame rate.
if (!main_timebase.num || !main_timebase.den)
main_timebase = (AVRational){1001, 60000};
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
avpriv_set_pts_info(st, 32, main_timebase.num, main_timebase.den);
}
return 0;
}
#define READ_ONE() \
{ \
if (!max_interval-- || pb->eof_reached) \
goto out; \
tmp = tmp << 8 | avio_r8(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;
AVIOContext *pb = s->pb;
GXFPktType type;
tmp = avio_rb32(pb);
start:
while (tmp)
READ_ONE();
READ_ONE();
if (tmp != 1)
goto start;
last_pos = avio_tell(pb);
if (avio_seek(pb, -5, SEEK_CUR) < 0)
goto out;
if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {
if (avio_seek(pb, last_pos, SEEK_SET) < 0)
goto out;
goto start;
}
avio_r8(pb);
cur_track = avio_r8(pb);
cur_timestamp = avio_rb32(pb);
last_found_pos = avio_tell(pb) - 16 - 6;
if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {
if (avio_seek(pb, last_pos, SEEK_SET) >= 0)
goto start;
}
out:
if (last_found_pos)
avio_seek(pb, last_found_pos, SEEK_SET);
return cur_timestamp;
}
static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
AVIOContext *pb = s->pb;
GXFPktType pkt_type;
int pkt_len;
struct gxf_stream_info *si = s->priv_data;
while (!pb->eof_reached) {
AVStream *st;
int track_type, track_id, ret;
int field_nr, field_info, skip = 0;
int stream_index;
if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
if (!pb->eof_reached)
av_log(s, AV_LOG_ERROR, "sync lost\n");
return -1;
}
if (pkt_type == PKT_FLT) {
gxf_read_index(s, pkt_len);
continue;
}
if (pkt_type != PKT_MEDIA) {
avio_skip(pb, pkt_len);
continue;
}
if (pkt_len < 16) {
av_log(s, AV_LOG_ERROR, "invalid media packet length\n");
continue;
}
pkt_len -= 16;
track_type = avio_r8(pb);
track_id = avio_r8(pb);
stream_index = get_sindex(s, track_id, track_type);
if (stream_index < 0)
return stream_index;
st = s->streams[stream_index];
field_nr = avio_rb32(pb);
field_info = avio_rb32(pb);
avio_rb32(pb); // "timeline" field number
avio_r8(pb); // flags
avio_r8(pb); // reserved
if (st->codecpar->codec_id == AV_CODEC_ID_PCM_S24LE ||
st->codecpar->codec_id == AV_CODEC_ID_PCM_S16LE) {
int first = field_info >> 16;
int last = field_info & 0xffff; // last is exclusive
int bps = av_get_bits_per_sample(st->codecpar->codec_id)>>3;
if (first <= last && last*bps <= pkt_len) {
avio_skip(pb, first*bps);
skip = pkt_len - last*bps;
pkt_len = (last-first)*bps;
} else
av_log(s, AV_LOG_ERROR, "invalid first and last sample values\n");
}
ret = av_get_packet(pb, pkt, pkt_len);
if (skip)
avio_skip(pb, skip);
pkt->stream_index = stream_index;
pkt->dts = field_nr;
//set duration manually for DV or else lavf misdetects the frame rate
if (st->codecpar->codec_id == AV_CODEC_ID_DVVIDEO)
pkt->duration = si->fields_per_frame;
return ret;
}
return AVERROR(EIO);
}
static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
int res = 0;
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);
res = avio_seek(s->pb, pos, SEEK_SET);
if (res < 0)
return res;
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) {
AVIOContext *pb = s->pb;
int64_t res;
if (avio_seek(pb, *pos, SEEK_SET) < 0)
return AV_NOPTS_VALUE;
res = gxf_resync_media(s, pos_limit - *pos, -1, -1);
*pos = avio_tell(pb);
return res;
}
AVInputFormat ff_gxf_demuxer = {
.name = "gxf",
.long_name = NULL_IF_CONFIG_SMALL("GXF (General eXchange Format)"),
.priv_data_size = sizeof(struct gxf_stream_info),
.read_probe = gxf_probe,
.read_header = gxf_header,
.read_packet = gxf_packet,
.read_seek = gxf_seek,
.read_timestamp = gxf_read_timestamp,
};