libavformat/mpc.c - vendor/opensource/ffmpeg - Git at Google

 /*
  * Musepack demuxer
  * Copyright (c) 2006 Konstantin Shishkov
  *
  * 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 "libavcodec/bitstream.h"
 #include "avformat.h"
 #include "id3v2.h"

 #define MPC_FRAMESIZE  1152
 #define DELAY_FRAMES   32

 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
 typedef struct {
     int64_t pos;
     int size, skip;
 }MPCFrame;

 typedef struct {
     int ver;
     uint32_t curframe, lastframe;
     uint32_t fcount;
     MPCFrame *frames;
     int curbits;
     int frames_noted;
 } MPCContext;

 static int mpc_probe(AVProbeData *p)
 {
     const uint8_t *d = p->buf;
     if (ff_id3v2_match(d)) {
         d += ff_id3v2_tag_len(d);
     }
     if (d+3 < p->buf+p->buf_size)
     if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
         return AVPROBE_SCORE_MAX;
     return 0;
 }

 static int mpc_read_header(AVFormatContext *s, AVFormatParameters *ap)
 {
     MPCContext *c = s->priv_data;
     AVStream *st;
     int t;

     t = get_le24(s->pb);
     if(t != MKTAG('M', 'P', '+', 0)){
         if(t != MKTAG('I', 'D', '3', 0)){
             av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
             return -1;
         }
         /* skip ID3 tags and try again */
         url_fskip(s->pb, 3);
         t  = get_byte(s->pb) << 21;
         t |= get_byte(s->pb) << 14;
         t |= get_byte(s->pb) <<  7;
         t |= get_byte(s->pb);
         av_log(s, AV_LOG_DEBUG, "Skipping %d(%X) bytes of ID3 data\n", t, t);
         url_fskip(s->pb, t);
         if(get_le24(s->pb) != MKTAG('M', 'P', '+', 0)){
             av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
             return -1;
         }
     }
     c->ver = get_byte(s->pb);
     if(c->ver != 0x07 && c->ver != 0x17){
         av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
         return -1;
     }
     c->fcount = get_le32(s->pb);
     if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
         av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
         return -1;
     }
     c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
     c->curframe = 0;
     c->lastframe = -1;
     c->curbits = 8;
     c->frames_noted = 0;

     st = av_new_stream(s, 0);
     if (!st)
         return AVERROR(ENOMEM);
     st->codec->codec_type = CODEC_TYPE_AUDIO;
     st->codec->codec_id = CODEC_ID_MUSEPACK7;
     st->codec->channels = 2;
     st->codec->bits_per_coded_sample = 16;

     st->codec->extradata_size = 16;
     st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
     get_buffer(s->pb, st->codec->extradata, 16);
     st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
     av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
     /* scan for seekpoints */
     s->start_time = 0;
     s->duration = (int64_t)c->fcount * MPC_FRAMESIZE * AV_TIME_BASE / st->codec->sample_rate;

     return 0;
 }

 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     MPCContext *c = s->priv_data;
     int ret, size, size2, curbits, cur = c->curframe;
     int64_t tmp, pos;

     if (c->curframe >= c->fcount)
         return -1;

     if(c->curframe != c->lastframe + 1){
         url_fseek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
         c->curbits = c->frames[c->curframe].skip;
     }
     c->lastframe = c->curframe;
     c->curframe++;
     curbits = c->curbits;
     pos = url_ftell(s->pb);
     tmp = get_le32(s->pb);
     if(curbits <= 12){
         size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
     }else{
         tmp = (tmp << 32) | get_le32(s->pb);
         size2 = (tmp >> (44 - curbits)) & 0xFFFFF;
     }
     curbits += 20;
     url_fseek(s->pb, pos, SEEK_SET);

     size = ((size2 + curbits + 31) & ~31) >> 3;
     if(cur == c->frames_noted){
         c->frames[cur].pos = pos;
         c->frames[cur].size = size;
         c->frames[cur].skip = curbits - 20;
         av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
         c->frames_noted++;
     }
     c->curbits = (curbits + size2) & 0x1F;

     if (av_new_packet(pkt, size) < 0)
         return AVERROR(EIO);

     pkt->data[0] = curbits;
     pkt->data[1] = (c->curframe > c->fcount);

     pkt->stream_index = 0;
     pkt->pts = cur;
     ret = get_buffer(s->pb, pkt->data + 4, size);
     if(c->curbits)
         url_fseek(s->pb, -4, SEEK_CUR);
     if(ret < size){
         av_free_packet(pkt);
         return AVERROR(EIO);
     }
     pkt->size = ret + 4;

     return 0;
 }

 static int mpc_read_close(AVFormatContext *s)
 {
     MPCContext *c = s->priv_data;

     av_freep(&c->frames);
     return 0;
 }

 /**
  * Seek to the given position
  * If position is unknown but is within the limits of file
  * then packets are skipped unless desired position is reached
  *
  * Also this function makes use of the fact that timestamp == frameno
  */
 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 {
     AVStream *st = s->streams[stream_index];
     MPCContext *c = s->priv_data;
     AVPacket pkt1, *pkt = &pkt1;
     int ret;
     int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
     uint32_t lastframe;

     /* if found, seek there */
     if (index >= 0){
         c->curframe = st->index_entries[index].pos;
         return 0;
     }
     /* if timestamp is out of bounds, return error */
     if(timestamp < 0 || timestamp >= c->fcount)
         return -1;
     timestamp -= DELAY_FRAMES;
     /* seek to the furthest known position and read packets until
        we reach desired position */
     lastframe = c->curframe;
     if(c->frames_noted) c->curframe = c->frames_noted - 1;
     while(c->curframe < timestamp){
         ret = av_read_frame(s, pkt);
         if (ret < 0){
             c->curframe = lastframe;
             return -1;
         }
         av_free_packet(pkt);
     }
     return 0;
 }


 AVInputFormat mpc_demuxer = {
     "mpc",
     NULL_IF_CONFIG_SMALL("Musepack"),
     sizeof(MPCContext),
     mpc_probe,
     mpc_read_header,
     mpc_read_packet,
     mpc_read_close,
     mpc_read_seek,
     .extensions = "mpc",
 };
	/*
	* Musepack demuxer
	* Copyright (c) 2006 Konstantin Shishkov
	*
	* 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 "libavcodec/bitstream.h"
	#include "avformat.h"
	#include "id3v2.h"

	#define MPC_FRAMESIZE 1152
	#define DELAY_FRAMES 32

	static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
	typedef struct {
	int64_t pos;
	int size, skip;
	}MPCFrame;

	typedef struct {
	int ver;
	uint32_t curframe, lastframe;
	uint32_t fcount;
	MPCFrame *frames;
	int curbits;
	int frames_noted;
	} MPCContext;

	static int mpc_probe(AVProbeData *p)
	{
	const uint8_t *d = p->buf;
	if (ff_id3v2_match(d)) {
	d += ff_id3v2_tag_len(d);
	}
	if (d+3 < p->buf+p->buf_size)
	if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 \|\| d[3] == 0x7))
	return AVPROBE_SCORE_MAX;
	return 0;
	}

	static int mpc_read_header(AVFormatContext s, AVFormatParameters ap)
	{
	MPCContext *c = s->priv_data;
	AVStream *st;
	int t;

	t = get_le24(s->pb);
	if(t != MKTAG('M', 'P', '+', 0)){
	if(t != MKTAG('I', 'D', '3', 0)){
	av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
	return -1;
	}
	/* skip ID3 tags and try again */
	url_fskip(s->pb, 3);
	t = get_byte(s->pb) << 21;
	t \|= get_byte(s->pb) << 14;
	t \|= get_byte(s->pb) << 7;
	t \|= get_byte(s->pb);
	av_log(s, AV_LOG_DEBUG, "Skipping %d(%X) bytes of ID3 data\n", t, t);
	url_fskip(s->pb, t);
	if(get_le24(s->pb) != MKTAG('M', 'P', '+', 0)){
	av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
	return -1;
	}
	}
	c->ver = get_byte(s->pb);
	if(c->ver != 0x07 && c->ver != 0x17){
	av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
	return -1;
	}
	c->fcount = get_le32(s->pb);
	if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
	av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
	return -1;
	}
	c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
	c->curframe = 0;
	c->lastframe = -1;
	c->curbits = 8;
	c->frames_noted = 0;

	st = av_new_stream(s, 0);
	if (!st)
	return AVERROR(ENOMEM);
	st->codec->codec_type = CODEC_TYPE_AUDIO;
	st->codec->codec_id = CODEC_ID_MUSEPACK7;
	st->codec->channels = 2;
	st->codec->bits_per_coded_sample = 16;

	st->codec->extradata_size = 16;
	st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
	get_buffer(s->pb, st->codec->extradata, 16);
	st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
	av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
	/* scan for seekpoints */
	s->start_time = 0;
	s->duration = (int64_t)c->fcount * MPC_FRAMESIZE * AV_TIME_BASE / st->codec->sample_rate;

	return 0;
	}

	static int mpc_read_packet(AVFormatContext s, AVPacket pkt)
	{
	MPCContext *c = s->priv_data;
	int ret, size, size2, curbits, cur = c->curframe;
	int64_t tmp, pos;

	if (c->curframe >= c->fcount)
	return -1;

	if(c->curframe != c->lastframe + 1){
	url_fseek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
	c->curbits = c->frames[c->curframe].skip;
	}
	c->lastframe = c->curframe;
	c->curframe++;
	curbits = c->curbits;
	pos = url_ftell(s->pb);
	tmp = get_le32(s->pb);
	if(curbits <= 12){
	size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
	}else{
	tmp = (tmp << 32) \| get_le32(s->pb);
	size2 = (tmp >> (44 - curbits)) & 0xFFFFF;
	}
	curbits += 20;
	url_fseek(s->pb, pos, SEEK_SET);

	size = ((size2 + curbits + 31) & ~31) >> 3;
	if(cur == c->frames_noted){
	c->frames[cur].pos = pos;
	c->frames[cur].size = size;
	c->frames[cur].skip = curbits - 20;
	av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
	c->frames_noted++;
	}
	c->curbits = (curbits + size2) & 0x1F;

	if (av_new_packet(pkt, size) < 0)
	return AVERROR(EIO);

	pkt->data[0] = curbits;
	pkt->data[1] = (c->curframe > c->fcount);

	pkt->stream_index = 0;
	pkt->pts = cur;
	ret = get_buffer(s->pb, pkt->data + 4, size);
	if(c->curbits)
	url_fseek(s->pb, -4, SEEK_CUR);
	if(ret < size){
	av_free_packet(pkt);
	return AVERROR(EIO);
	}
	pkt->size = ret + 4;

	return 0;
	}

	static int mpc_read_close(AVFormatContext *s)
	{
	MPCContext *c = s->priv_data;

	av_freep(&c->frames);
	return 0;
	}

	/**
	* Seek to the given position
	* If position is unknown but is within the limits of file
	* then packets are skipped unless desired position is reached
	*
	* Also this function makes use of the fact that timestamp == frameno
	*/
	static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
	{
	AVStream *st = s->streams[stream_index];
	MPCContext *c = s->priv_data;
	AVPacket pkt1, *pkt = &pkt1;
	int ret;
	int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
	uint32_t lastframe;

	/* if found, seek there */
	if (index >= 0){
	c->curframe = st->index_entries[index].pos;
	return 0;
	}
	/* if timestamp is out of bounds, return error */
	if(timestamp < 0 \|\| timestamp >= c->fcount)
	return -1;
	timestamp -= DELAY_FRAMES;
	/* seek to the furthest known position and read packets until
	we reach desired position */
	lastframe = c->curframe;
	if(c->frames_noted) c->curframe = c->frames_noted - 1;
	while(c->curframe < timestamp){
	ret = av_read_frame(s, pkt);
	if (ret < 0){
	c->curframe = lastframe;
	return -1;
	}
	av_free_packet(pkt);
	}
	return 0;
	}


	AVInputFormat mpc_demuxer = {
	"mpc",
	NULL_IF_CONFIG_SMALL("Musepack"),
	sizeof(MPCContext),
	mpc_probe,
	mpc_read_header,
	mpc_read_packet,
	mpc_read_close,
	mpc_read_seek,
	.extensions = "mpc",
	};