[FFmpeg-devel] [PATCH] Core Audio Format demuxer (v2)

[Michael Niedermayer]

On Mon, Aug 10, 2009 at 11:19:27PM +1000, Peter Ross wrote:
> On Sun, Aug 09, 2009 at 07:41:05PM +1000, Peter Ross wrote:
> > Enclosed is a revised version of Justin Ruggles CAF demuxer.
> > 
> > Samples: http://samples.mplayerhq.hu/A-codecs/caf/
> > Original thread: http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2007-April/026491.html
> 
> Revised patch enclosed.
> 
> -- Peter
> (A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)

>  isom.h |    4 ++++
>  mov.c  |   35 ++++++++++++++++++++---------------
>  2 files changed, 24 insertions(+), 15 deletions(-)
> 542413cf2cd3ad4a0a49d44780f5b56012185462  0001-Make-mov-LPCM-and-AAC-parsing-functions-public-r2.patch
> From 8bf5aa9e5e24f86a5721c358fd30270cb8c3e39d Mon Sep 17 00:00:00 2001
> From: pross <pross at tablet.(none)>
> Date: Mon, 10 Aug 2009 21:15:50 +1000
> Subject: [PATCH] Make mov LPCM and AAC parsing functions public.

left to baptiste to review

[...]


> +static int probe(AVProbeData *p)
> +{

> +    if (p->buf_size < 6)
> +        return 0;

this check is unneeded, see AVPROBE_PADDING_SIZE


> +    if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
> +        return AVPROBE_SCORE_MAX;
> +    return 0;
> +}
> +

> +static int read_desc(AVFormatContext *s, int64_t size)
> +{
> +    ByteIOContext *pb = s->pb;
> +    CaffContext *caf  = s->priv_data;
> +    AVStream *st;
> +    int flags;
> +
> +    /* check chunk size */
> +    if (size != 32)
> +        return AVERROR_INVALIDDATA;

hmm, is there really a point to pass wsize if it has to be a specific
value anyway?


> +
> +    /* new audio stream */
> +    st = av_new_stream(s, 0);
> +    if (!st)
> +        return AVERROR_NOMEM;
> +
> +    /* parse format description */
> +    st->codec->codec_type  = CODEC_TYPE_AUDIO;
> +    st->codec->sample_rate = av_int2dbl(get_be64(pb));
> +    st->codec->codec_tag   = get_be32(pb);
> +    flags = get_be32(pb);
> +    caf->bytes_per_packet  = get_be32(pb);
> +    st->codec->block_align = caf->bytes_per_packet;
> +    caf->frames_per_packet = get_be32(pb);
> +    st->codec->channels    = get_be32(pb);
> +    st->codec->bits_per_coded_sample = get_be32(pb);
> +
> +    /* calculate bit rate for constant size packets */
> +    if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
> +        st->codec->bit_rate = st->codec->sample_rate * caf->bytes_per_packet * 8;
> +        st->codec->bit_rate /= caf->frames_per_packet;

st->codec->bit_rate = st->codec->sample_rate * caf->bytes_per_packet * 8
                     / caf->frames_per_packet;


[...]
> +static int read_pakt(AVFormatContext *s, int64_t size)
> +{
> +    ByteIOContext *pb = s->pb;
> +    CaffContext *caf  = s->priv_data;
> +    int64_t bcount=0, fcount=0, ccount;
> +    int i;
> +
> +    ccount = url_ftell(pb);
> +
> +    caf->num_packets = get_be64(pb);
> +    if (caf->num_packets < 0 || (INT32_MAX/caf->num_packets) < sizeof(PacketTableEntry))
> +        return AVERROR_INVALIDDATA;

id write INT32_MAX / sizeof(PacketTableEntry) < caf->num_packets
because the left side is a constant and known at compile time


> +    caf->packet_table = av_mallocz(caf->num_packets * sizeof(PacketTableEntry));
> +    if (!caf->packet_table)
> +        return AVERROR_NOMEM;
> +
> +    caf->has_packet_table = 1;
> +    caf->num_frames = get_be64(pb);  /* valid frames */
> +    caf->num_frames += get_be32(pb); /* priming frames */
> +    caf->num_frames += get_be32(pb); /* remainder frames */
> +
> +    for(i=0; i<caf->num_packets; i++) {

> +        if (!caf->bytes_per_packet)
> +            caf->packet_table[i].bytes = ff_mp4_read_descr_len(pb);
> +        else

if(){
}else
reduces future diff size 


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When you are offended at any man's fault, turn to yourself and study your
own failings. Then you will forget your anger. -- Epictetus
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