[FFmpeg-devel] [PATCH] MOV: support stz2 "Compact Sample Size Box"

[Alex Converse]

On Fri, Mar 6, 2009 at 4:42 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Fri, Mar 06, 2009 at 03:07:03PM -0500, Alex Converse wrote:
>> 2009/3/3 Michael Niedermayer <michaelni at gmx.at>:
>> > On Tue, Mar 03, 2009 at 02:45:15AM -0500, Alex Converse wrote:
>> > [...]
>> >> @@ -1143,8 +1150,33 @@ static int mov_read_stsz(MOVContext *c, ByteIOContext *pb, MOVAtom atom)
>> >> ? ? ?if (!sc->sample_sizes)
>> >> ? ? ? ? ?return AVERROR(ENOMEM);
>> >>
>> >> + ? ?switch(field_size) {
>> >> + ? ?case 4:
>> >> + ? ? ? ?for(i=0; i<entries-1; i+=2) {
>> >> + ? ? ? ? ? ?int field = get_byte(pb);
>> >> + ? ? ? ? ? ?sc->sample_sizes[i ?] = field >> 4;
>> >> + ? ? ? ? ? ?sc->sample_sizes[i+1] = field & 0xF;
>> >> + ? ? ? ?}
>> >> + ? ? ? ?if(entries&1) {
>> >> + ? ? ? ? ? ?sc->sample_sizes[entries-1] = get_byte(pb) >> 4;
>> >> + ? ? ? ?}
>> >> + ? ? ? ?break;
>> >> + ? ?case 8:
>> >> + ? ? ? ?for(i=0; i<entries; i++)
>> >> + ? ? ? ? ? ?sc->sample_sizes[i] = get_byte(pb);
>> >> + ? ? ? ?break;
>> >> + ? ?case 16:
>> >> + ? ? ? ?for(i=0; i<entries; i++)
>> >> + ? ? ? ? ? ?sc->sample_sizes[i] = get_be16(pb);
>> >> + ? ? ? ?break;
>> >> + ? ?case 32:
>> >> ? ? ?for(i=0; i<entries; i++)
>> >> ? ? ? ? ?sc->sample_sizes[i] = get_be32(pb);
>> >> + ? ? ? ?break;
>> >> + ? ?default:
>> >> + ? ? ? ?av_log(c->fc, AV_LOG_ERROR, "Invalid sample field size %d\n", field_size);
>> >> + ? ? ? ?return -1;
>> >> + ? ?}
>> >
>> > I think that should be using GetBitContext
>> >
>>
>> Are you sure that's the best approach?
>
> no, but iam fairly sure above is worse ;)
> this code isnt speed critical, theres no sense in bloating the
> loops up like that ...
>

Is this better?

[...]

--Alex
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