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by Sérgio Benjamim
FFmpeg 2.7.1 source for ppsspp. |
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/*
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* Linux Media Labs MPEG-4 demuxer
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* Copyright (c) 2008 Ivo van Poorten
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*
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* Due to a lack of sample files, only files with one channel are supported.
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* u-law and ADPCM audio are unsupported for the same reason.
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg 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 FFmpeg; 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 "libavutil/intreadwrite.h" |
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#include "avformat.h" |
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#include "internal.h" |
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#define LMLM4_I_FRAME 0x00
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#define LMLM4_P_FRAME 0x01
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#define LMLM4_B_FRAME 0x02
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#define LMLM4_INVALID 0x03
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#define LMLM4_MPEG1L2 0x04
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#define LMLM4_MAX_PACKET_SIZE 1024 * 1024
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static int lmlm4_probe(AVProbeData *pd) |
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{
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const unsigned char *buf = pd->buf; |
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unsigned int frame_type, packet_size; |
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frame_type = AV_RB16(buf + 2); |
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packet_size = AV_RB32(buf + 4); |
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if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size && |
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frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) { |
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if (frame_type == LMLM4_MPEG1L2) { |
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if ((AV_RB16(buf + 8) & 0xfffe) != 0xfffc) |
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return 0; |
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/* I could calculate the audio framesize and compare with
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* packet_size-8, but that seems overkill */
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return AVPROBE_SCORE_MAX / 3; |
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} else if (AV_RB24(buf + 8) == 0x000001) { /* PES Signal */ |
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return AVPROBE_SCORE_MAX / 5; |
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}
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}
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return 0; |
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}
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static int lmlm4_read_header(AVFormatContext *s) |
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{
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AVStream *st; |
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if (!(st = avformat_new_stream(s, NULL))) |
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return AVERROR(ENOMEM); |
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st->codec->codec_type = AVMEDIA_TYPE_VIDEO; |
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st->codec->codec_id = AV_CODEC_ID_MPEG4; |
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st->need_parsing = AVSTREAM_PARSE_HEADERS; |
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avpriv_set_pts_info(st, 64, 1001, 30000); |
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if (!(st = avformat_new_stream(s, NULL))) |
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return AVERROR(ENOMEM); |
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st->codec->codec_type = AVMEDIA_TYPE_AUDIO; |
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st->codec->codec_id = AV_CODEC_ID_MP2; |
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st->need_parsing = AVSTREAM_PARSE_HEADERS; |
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/* the parameters will be extracted from the compressed bitstream */
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return 0; |
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}
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static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) |
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{
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AVIOContext *pb = s->pb; |
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int ret; |
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unsigned int frame_type, packet_size, padding, frame_size; |
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avio_rb16(pb); /* channel number */ |
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frame_type = avio_rb16(pb); |
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packet_size = avio_rb32(pb); |
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padding = -packet_size & 511; |
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frame_size = packet_size - 8; |
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if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) { |
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av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n"); |
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return AVERROR(EIO); |
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}
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if (packet_size > LMLM4_MAX_PACKET_SIZE || packet_size<=8) { |
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av_log(s, AV_LOG_ERROR, "packet size %d is invalid\n", packet_size); |
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return AVERROR(EIO); |
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}
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if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0) |
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return AVERROR(EIO); |
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avio_skip(pb, padding); |
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switch (frame_type) { |
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case LMLM4_I_FRAME: |
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pkt->flags = AV_PKT_FLAG_KEY; |
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case LMLM4_P_FRAME: |
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case LMLM4_B_FRAME: |
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pkt->stream_index = 0; |
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break; |
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case LMLM4_MPEG1L2: |
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pkt->stream_index = 1; |
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break; |
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}
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return ret; |
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}
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AVInputFormat ff_lmlm4_demuxer = { |
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.name = "lmlm4", |
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.long_name = NULL_IF_CONFIG_SMALL("raw lmlm4"), |
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.read_probe = lmlm4_probe, |
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.read_header = lmlm4_read_header, |
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.read_packet = lmlm4_read_packet, |
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};
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