mirror of
https://github.com/FFmpeg/FFmpeg.git
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253 lines
8.0 KiB
C
253 lines
8.0 KiB
C
/*
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* GXF demuxer.
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* Copyright (c) 2006 Reimar Doeffinger.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avformat.h"
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typedef enum {
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PKT_MAP = 0xbc,
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PKT_MEDIA = 0xbf,
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PKT_EOS = 0xfb,
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PKT_FLT = 0xfc,
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PKT_UMF = 0xfd
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} pkt_type_t;
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/**
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* \brief parses a packet header, extracting type and length
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* \param pb ByteIOContext to read header from
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* \param type detected packet type is stored here
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* \param length detected packet length, excluding header is stored here
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* \return 0 if header not found or contains invalid data, 1 otherwise
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*/
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static int parse_packet_header(ByteIOContext *pb, pkt_type_t *type, int *length) {
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if (get_be32(pb))
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return 0;
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if (get_byte(pb) != 1)
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return 0;
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*type = get_byte(pb);
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*length = get_be32(pb);
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if ((*length >> 24) || *length < 16)
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return 0;
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*length -= 16;
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if (get_be32(pb))
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return 0;
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if (get_byte(pb) != 0xe1)
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return 0;
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if (get_byte(pb) != 0xe2)
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return 0;
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return 1;
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}
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/**
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* \brief check if file starts with a PKT_MAP header
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*/
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static int gxf_probe(AVProbeData *p) {
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static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
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static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
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if (p->buf_size < 16)
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return 0;
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if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
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!memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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/**
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* \brief gets the stream index for the track with the specified id, creates new
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* stream if not found
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* \param stream id of stream to find / add
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* \param format stream format identifier
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*/
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static int get_sindex(AVFormatContext *s, int id, int format) {
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int i;
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AVStream *st = NULL;
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for (i = 0; i < s->nb_streams; i++) {
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if (s->streams[i]->id == id)
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return i;
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}
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st = av_new_stream(s, id);
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switch (format) {
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case 3:
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case 4:
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st->codec->codec_type = CODEC_TYPE_VIDEO;
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st->codec->codec_id = CODEC_ID_MJPEG;
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st->codec->codec_tag = MKTAG('M', 'J', 'P', 'G');
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break;
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case 13:
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case 15:
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st->codec->codec_type = CODEC_TYPE_VIDEO;
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st->codec->codec_id = CODEC_ID_DVVIDEO;
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st->codec->codec_tag = MKTAG('d', 'v', 'c', ' ');
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break;
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case 14:
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case 16:
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st->codec->codec_type = CODEC_TYPE_VIDEO;
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st->codec->codec_id = CODEC_ID_DVVIDEO;
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st->codec->codec_tag = MKTAG('d', 'v', 'c', 'p');
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break;
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case 11:
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case 12:
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case 20:
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st->codec->codec_type = CODEC_TYPE_VIDEO;
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st->codec->codec_id = CODEC_ID_MPEG2VIDEO;
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st->codec->codec_tag = MKTAG('M', 'P', 'G', '2');
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break;
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case 22:
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case 23:
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st->codec->codec_type = CODEC_TYPE_VIDEO;
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st->codec->codec_id = CODEC_ID_MPEG1VIDEO;
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st->codec->codec_tag = MKTAG('M', 'P', 'G', '1');
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break;
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case 9:
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st->codec->codec_type = CODEC_TYPE_AUDIO;
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st->codec->codec_id = CODEC_ID_PCM_S24LE;
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st->codec->codec_tag = 0x1;
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st->codec->channels = 1;
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st->codec->sample_rate = 48000;
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st->codec->bit_rate = 3 * 1 * 48000 * 8;
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st->codec->block_align = 3 * 1;
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st->codec->bits_per_sample = 24;
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break;
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case 10:
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st->codec->codec_type = CODEC_TYPE_AUDIO;
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st->codec->codec_id = CODEC_ID_PCM_S16LE;
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st->codec->codec_tag = 0x1;
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st->codec->channels = 1;
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st->codec->sample_rate = 48000;
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st->codec->bit_rate = 2 * 1 * 48000 * 8;
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st->codec->block_align = 2 * 1;
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st->codec->bits_per_sample = 16;
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break;
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case 17:
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st->codec->codec_type = CODEC_TYPE_AUDIO;
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st->codec->codec_id = CODEC_ID_AC3;
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st->codec->codec_tag = 0x2000;
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st->codec->channels = 2;
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st->codec->sample_rate = 48000;
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break;
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default:
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st->codec->codec_type = CODEC_TYPE_UNKNOWN;
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st->codec->codec_id = CODEC_ID_NONE;
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break;
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}
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return s->nb_streams - 1;
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}
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static int gxf_header(AVFormatContext *s, AVFormatParameters *ap) {
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ByteIOContext *pb = &s->pb;
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pkt_type_t pkt_type;
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int map_len;
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int len;
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if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
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av_log(s, AV_LOG_ERROR, "GXF: map packet not found\n");
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return 0;
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}
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map_len -= 2;
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if (get_byte(pb) != 0x0e0 || get_byte(pb) != 0xff) {
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av_log(s, AV_LOG_ERROR, "GXF: unknown version or invalid map preamble\n");
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return 0;
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}
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map_len -= 2;
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len = get_be16(pb); // length of material data section
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if (len > map_len) {
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av_log(s, AV_LOG_ERROR, "GXF: material data longer than map data\n");
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return 0;
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}
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map_len -= len;
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url_fskip(pb, len);
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map_len -= 2;
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len = get_be16(pb); // length of track description
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if (len > map_len) {
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av_log(s, AV_LOG_ERROR, "GXF: track description longer than map data\n");
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return 0;
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}
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map_len -= len;
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while (len > 0) {
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int track_type, track_id, track_len;
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len -= 4;
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track_type = get_byte(pb);
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track_id = get_byte(pb);
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track_len = get_be16(pb);
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len -= track_len;
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url_fskip(pb, track_len);
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if (!(track_type & 0x80)) {
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av_log(s, AV_LOG_ERROR, "GXF: invalid track type %x\n", track_type);
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continue;
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}
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track_type &= 0x7f;
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if ((track_id & 0xc0) != 0xc0) {
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av_log(s, AV_LOG_ERROR, "GXF: invalid track id %x\n", track_id);
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continue;
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}
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track_id &= 0x3f;
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get_sindex(s, track_id, track_type);
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}
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if (len < 0)
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av_log(s, AV_LOG_ERROR, "GXF: invalid track description length specified\n");
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if (map_len)
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url_fskip(pb, map_len);
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return 0;
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}
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static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
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ByteIOContext *pb = &s->pb;
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pkt_type_t pkt_type;
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int pkt_len;
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while (!url_feof(pb)) {
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int track_type, track_id, ret;
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if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
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if (!url_feof(pb))
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av_log(s, AV_LOG_ERROR, "GXF: sync lost\n");
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return -1;
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}
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if (pkt_type != PKT_MEDIA) {
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url_fskip(pb, pkt_len);
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continue;
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}
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if (pkt_len < 16) {
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av_log(s, AV_LOG_ERROR, "GXF: invalid media packet length\n");
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continue;
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}
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pkt_len -= 16;
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track_type = get_byte(pb);
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track_id = get_byte(pb);
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get_be32(pb); // field number
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get_be32(pb); // field information
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get_be32(pb); // "timeline" field number
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get_byte(pb); // flags
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get_byte(pb); // reserved
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// NOTE: there is also data length information in the
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// field information, it might be better to take this int account
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// as well.
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ret = av_get_packet(pb, pkt, pkt_len);
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pkt->stream_index = get_sindex(s, track_id, track_type);
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return ret;
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}
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return AVERROR_IO;
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}
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AVInputFormat gxf_demuxer = {
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"gxf",
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"GXF format",
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0,
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gxf_probe,
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gxf_header,
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gxf_packet,
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NULL,
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NULL,
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};
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