[FFmpeg-devel] [PATCH] Lego Mindstorms RSO de/muxer (copied from au.c)
Rafaël Carré
rafael.carre
Fri Jul 16 06:22:35 CEST 2010
On Fri, 16 Jul 2010 05:22:46 +0200
Michael Niedermayer <michaelni at gmx.at> wrote:
> On Thu, Jul 15, 2010 at 04:44:49PM +0200, Rafa?l Carr? wrote:
> [...]
> > + * 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 "libavutil/intreadwrite.h"
> > +#include "avformat.h"
> > +#include "raw.h"
> > +#include "riff.h"
> > +#include "rso.h"
> > +
>
> > +static int rso_probe(AVProbeData *p)
> > +{
> > + uint16_t rate, loop;
>
> why uint16_t?
Those are 16 bits values, do you suggest using int instead?
> > +
> > + if (p->buf_size < RSO_HEADER_SIZE)
> > + return 0;
>
> probably unneeded
Reading ff_probe_input_buffer() it seems the buffer will be at least
AVPROBE_PADDING_SIZE (== 32) bytes so it could be removed
> > + bpp = av_get_bits_per_sample(codec);
> > + st->duration = size << 3 / bpp;
>
> is this correct?
Yes, number of samples = size in bytes * 8 / bits per sample
Although the variable should be named bps and not bpp
Also since bits per sample is 8 (PCM_U8) or 4 (ADPCM_IMA_WAV) I think it
should use av_log2() + shift, e.g. (size << 3) >> av_log2(bps)
> [...]
> > +static int rso_write_header(AVFormatContext *s)
> > +{
> > + ByteIOContext *pb = s->pb;
> > + AVCodecContext *enc = s->streams[0]->codec;
> > +
> > + if (!enc->codec_tag)
> > + return -1;
> > +
> > + if (enc->channels != 1) {
> > + av_log(s, AV_LOG_ERROR, "RSO only supports mono\n");
> > + return -1;
> > + }
> > +
> > + if (url_is_streamed(s->pb)) {
> > + av_log(s, AV_LOG_ERROR, "muxer does not support non
> > seekable output\n");
> > + return -1;
> > + }
> > +
> > + /* XXX: find legal sample rates */
> > + if (enc->sample_rate >= 1u<<16) {
> > + av_log(s, AV_LOG_ERROR, "Sample rate must be < 65536\n");
> > + return -1;
> > + }
> > +
> > + if (enc->codec_id == CODEC_ID_ADPCM_IMA_WAV) {
> > + av_log(s, AV_LOG_ERROR, "ADPCM in RSO not implemented\n");
> > + return -1;
> > + }
> > +
> > + s->priv_data = NULL;
>
> how did it become non null ?
Dunno, I copied it straight from au.c and didn't check if it was needed.
I'll check and send another patch
--
Rafa?l Carr?
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