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fcplay: Decode the AAC header to set correct codec->format value #34

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fcplay: Decode the AAC header to set correct codec->format value #34

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33 changes: 32 additions & 1 deletion src/utils-lgpl/fcplay.c
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Original file line number Diff line number Diff line change
Expand Up @@ -199,6 +199,34 @@ static int get_codec_id(int codec_id)
}
}

static unsigned int get_aac_format(AVFormatContext *ctx)
{
unsigned char buf[4];
int n;

avio_seek(ctx->pb, 0, SEEK_SET);
n = avio_read(ctx->pb, buf, sizeof(buf));
avio_seek(ctx->pb, 0, SEEK_SET);

if (n < 2)
return 0;

/* ADIF magic: "ADIF" */
if (n == 4 && buf[0] == 0x41 && buf[1] == 0x44 && buf[2] == 0x49 && buf[3] == 0x46)
return SND_AUDIOSTREAMFORMAT_ADIF;

/* ADTS sync word: 0xFFF... */
if (buf[0] == 0xff && (buf[1] & 0xf0) == 0xf0) {
/* MPEG ID bit (bit 3 of buf[1]): 0 = MPEG-4, 1 = MPEG-2 */
if ((buf[1] >> 3) & 0x1)
return SND_AUDIOSTREAMFORMAT_MP2ADTS;
else
return SND_AUDIOSTREAMFORMAT_MP4ADTS;
}

return 0;
}

static int parse_file(char *file, struct snd_codec *codec)
{
AVFormatContext *ctx = NULL;
Expand Down Expand Up @@ -245,7 +273,10 @@ static int parse_file(char *file, struct snd_codec *codec)
codec->sample_rate = stream->codecpar->sample_rate;
codec->bit_rate = ctx->bit_rate;
codec->profile = stream->codecpar->profile;
codec->format = 0; /* need codec format type */
if (codec->id == SND_AUDIOCODEC_AAC)
codec->format = get_aac_format(ctx);
else
codec->format = 0;
codec->align = stream->codecpar->block_align;
codec->level = 0;
codec->rate_control = 0;
Expand Down