/**
* Determine the size of an inline header.
* @param buf input buffer, starting with the "fLaC" marker
* @param buf_size buffer size
* @return number of bytes in the header, or 0 if more data is needed
*/
static int get_metadata_size(const uint8_t *buf, int buf_size)
{
int metadata_last, metadata_size;
const uint8_t *buf_end = buf + buf_size;
buf += 4;
do {
ff_flac_parse_block_header(buf, &metadata_last, NULL, &metadata_size);
buf += 4;
if (buf + metadata_size > buf_end) {
/* need more data in order to read the complete header */
return 0;
}
buf += metadata_size;
} while (!metadata_last);
return buf_size - (buf_end - buf);
}
/**
* Parse the STREAMINFO from an inline header.
* @param s the flac decoding context
* @param buf input buffer, starting with the "fLaC" marker
* @param buf_size buffer size
* @return non-zero if metadata is invalid
*/
static int parse_streaminfo(FLACContext *s, const uint8_t *buf, int buf_size)
{
int metadata_type, metadata_size;
if (buf_size < FLAC_STREAMINFO_SIZE+8) {
/* need more data */
return 0;
}
ff_flac_parse_block_header(&buf[4], NULL, &metadata_type, &metadata_size);
if (metadata_type != FLAC_METADATA_TYPE_STREAMINFO ||
metadata_size != FLAC_STREAMINFO_SIZE) {
return AVERROR_INVALIDDATA;
}
ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s, &buf[8]);
allocate_buffers(s);
s->got_streaminfo = 1;
return 0;
}
static int flac_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
uint8_t buf[ID3v2_HEADER_SIZE];
int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
uint8_t header[4];
uint8_t *buffer=NULL;
AVStream *st = av_new_stream(s, 0);
if (!st)
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_FLAC;
st->need_parsing = AVSTREAM_PARSE_FULL;
/* the parameters will be extracted from the compressed bitstream */
/* skip ID3v2 header if found */
ret = get_buffer(s->pb, buf, ID3v2_HEADER_SIZE);
if (ret == ID3v2_HEADER_SIZE && ff_id3v2_match(buf)) {
int len = ff_id3v2_tag_len(buf);
url_fseek(s->pb, len - ID3v2_HEADER_SIZE, SEEK_CUR);
} else {
url_fseek(s->pb, 0, SEEK_SET);
}
/* if fLaC marker is not found, assume there is no header */
if (get_le32(s->pb) != MKTAG('f','L','a','C')) {
url_fseek(s->pb, -4, SEEK_CUR);
return 0;
}
/* process metadata blocks */
while (!url_feof(s->pb) && !metadata_last) {
get_buffer(s->pb, header, 4);
ff_flac_parse_block_header(header, &metadata_last, &metadata_type,
&metadata_size);
switch (metadata_type) {
/* allocate and read metadata block for supported types */
case FLAC_METADATA_TYPE_STREAMINFO:
case FLAC_METADATA_TYPE_VORBIS_COMMENT:
buffer = av_mallocz(metadata_size + FF_INPUT_BUFFER_PADDING_SIZE);
if (!buffer) {
return AVERROR(ENOMEM);
}
if (get_buffer(s->pb, buffer, metadata_size) != metadata_size) {
av_freep(&buffer);
return AVERROR(EIO);
}
break;
/* skip metadata block for unsupported types */
default:
ret = url_fseek(s->pb, metadata_size, SEEK_CUR);
if (ret < 0)
return ret;
}
if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {
FLACStreaminfo si;
/* STREAMINFO can only occur once */
if (found_streaminfo) {
av_freep(&buffer);
return AVERROR_INVALIDDATA;
}
if (metadata_size != FLAC_STREAMINFO_SIZE) {
av_freep(&buffer);
return AVERROR_INVALIDDATA;
}
found_streaminfo = 1;
st->codec->extradata = buffer;
st->codec->extradata_size = metadata_size;
buffer = NULL;
/* get codec params from STREAMINFO header */
ff_flac_parse_streaminfo(st->codec, &si, st->codec->extradata);
/* set time base and duration */
if (si.samplerate > 0) {
av_set_pts_info(st, 64, 1, si.samplerate);
if (si.samples > 0)
st->duration = si.samples;
}
} else {
/* STREAMINFO must be the first block */
if (!found_streaminfo) {
av_freep(&buffer);
return AVERROR_INVALIDDATA;
}
/* process supported blocks other than STREAMINFO */
if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
if (ff_vorbis_comment(s, &s->metadata, buffer, metadata_size)) {
av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
}
}
av_freep(&buffer);
}
}
return 0;
}
