[pulseaudio-discuss] [PATCH v3 3/3] resampler: Add support for resamplers that consume less data than asked.
Tanu Kaskinen
tanuk at iki.fi
Wed May 9 23:19:23 PDT 2012
libsamplerate_resample() assumed that src_process() would
always consume the whole input buffer. That was an invalid
assumption leading to crashes.
This patch adds a leftover memchunk for storing any
non-consumed input. When pa_resampler_run() is called next
time, the leftover is prepended to the new input.
Changes in v3:
- Make the calculations in pa_resampler_result() and
pa_resampler_max_block_size() more readable and more
correct.
- Rework the leftover storing: instead of using a dedicated
buffer for it, store it in the beginning of remap_buf.
This can avoid some memory copying. (The idea was
suggested by Wang Xingchao.)
- Use a generic save_leftover() function instead of doing
the leftover copying in the resampler implementation.
- Use the leftover logic also with the speex and ffmpeg
resamplers.
Changes in v2:
- If add_leftover() is called with zero-length input while
the leftover length is non-zero, we don't try to acquire
the input memblock.
- Instead of taking a reference to the original input in
libsamplerate_resample(), we copy the leftover data to a
new memblock. This is done, because otherwise, if the
input is one of the internal buffers, the data can get
overwritten before reading it in add_leftover().
- Store add_leftover_buf size in bytes instead of samples
(more convenient, but less consistent with other code).
BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=47156
---
src/pulsecore/resampler.c | 207 ++++++++++++++++++++++++++++++++-------------
1 file changed, 149 insertions(+), 58 deletions(-)
diff --git a/src/pulsecore/resampler.c b/src/pulsecore/resampler.c
index 258d1fe..e3fad30 100644
--- a/src/pulsecore/resampler.c
+++ b/src/pulsecore/resampler.c
@@ -61,9 +61,10 @@ struct pa_resampler {
pa_memchunk resample_buf;
pa_memchunk from_work_format_buf;
unsigned to_work_format_buf_samples;
- unsigned remap_buf_samples;
+ size_t remap_buf_size;
unsigned resample_buf_samples;
unsigned from_work_format_buf_samples;
+ pa_bool_t remap_buf_contains_leftover_data;
pa_sample_format_t work_format;
@@ -379,23 +380,39 @@ void pa_resampler_set_output_rate(pa_resampler *r, uint32_t rate) {
size_t pa_resampler_request(pa_resampler *r, size_t out_length) {
pa_assert(r);
- /* Let's round up here */
-
+ /* Let's round up here to make it more likely that the caller will get at
+ * least out_length amount of data from pa_resampler_run().
+ *
+ * We don't take the leftover into account here. If we did, then it might
+ * be in theory possible that this function would return 0 and
+ * pa_resampler_run() would also return 0. That could lead to infinite
+ * loops. When the leftover is ignored here, such loops would eventually
+ * terminate, because the leftover would grow each round, finally
+ * surpassing the minimum input threshold of the resampler. */
return (((((out_length + r->o_fz-1) / r->o_fz) * r->i_ss.rate) + r->o_ss.rate-1) / r->o_ss.rate) * r->i_fz;
}
size_t pa_resampler_result(pa_resampler *r, size_t in_length) {
+ size_t frames;
+
pa_assert(r);
- /* Let's round up here */
+ /* Let's round up here to ensure that the caller will always allocate big
+ * enough output buffer. */
+
+ frames = (in_length + r->i_fz - 1) / r->i_fz;
+
+ if (r->remap_buf_contains_leftover_data)
+ frames += r->remap_buf.length / (r->w_sz * r->o_ss.channels);
- return (((((in_length + r->i_fz-1) / r->i_fz) * r->o_ss.rate) + r->i_ss.rate-1) / r->i_ss.rate) * r->o_fz;
+ return ((frames * r->o_ss.rate + r->i_ss.rate - 1) / r->i_ss.rate) * r->o_fz;
}
size_t pa_resampler_max_block_size(pa_resampler *r) {
size_t block_size_max;
- pa_sample_spec ss;
- size_t fs;
+ pa_sample_spec max_ss;
+ size_t max_fs;
+ size_t frames;
pa_assert(r);
@@ -403,17 +420,21 @@ size_t pa_resampler_max_block_size(pa_resampler *r) {
/* We deduce the "largest" sample spec we're using during the
* conversion */
- ss.channels = (uint8_t) (PA_MAX(r->i_ss.channels, r->o_ss.channels));
+ max_ss.channels = (uint8_t) (PA_MAX(r->i_ss.channels, r->o_ss.channels));
/* We silently assume that the format enum is ordered by size */
- ss.format = PA_MAX(r->i_ss.format, r->o_ss.format);
- ss.format = PA_MAX(ss.format, r->work_format);
+ max_ss.format = PA_MAX(r->i_ss.format, r->o_ss.format);
+ max_ss.format = PA_MAX(max_ss.format, r->work_format);
- ss.rate = PA_MAX(r->i_ss.rate, r->o_ss.rate);
+ max_ss.rate = PA_MAX(r->i_ss.rate, r->o_ss.rate);
- fs = pa_frame_size(&ss);
+ max_fs = pa_frame_size(&max_ss);
+ frames = block_size_max / max_fs - EXTRA_FRAMES;
- return (((block_size_max/fs - EXTRA_FRAMES)*r->i_ss.rate)/ss.rate)*r->i_fz;
+ if (r->remap_buf_contains_leftover_data)
+ frames -= r->remap_buf.length / (r->w_sz * r->o_ss.channels);
+
+ return (frames * r->i_ss.rate / max_ss.rate) * r->i_fz;
}
void pa_resampler_reset(pa_resampler *r) {
@@ -421,6 +442,8 @@ void pa_resampler_reset(pa_resampler *r) {
if (r->impl_reset)
r->impl_reset(r);
+
+ r->remap_buf_contains_leftover_data = FALSE;
}
pa_resample_method_t pa_resampler_get_method(pa_resampler *r) {
@@ -1101,41 +1124,74 @@ static pa_memchunk* convert_to_work_format(pa_resampler *r, pa_memchunk *input)
}
static pa_memchunk *remap_channels(pa_resampler *r, pa_memchunk *input) {
- unsigned in_n_samples, out_n_samples, n_frames;
+ unsigned in_n_samples, out_n_samples, in_n_frames, out_n_frames;
void *src, *dst;
- pa_remap_t *remap;
+ size_t leftover_length = 0;
+ pa_bool_t have_leftover;
pa_assert(r);
pa_assert(input);
pa_assert(input->memblock);
- /* Remap channels and place the result in remap_buf. */
+ /* Remap channels and place the result in remap_buf. There may be leftover
+ * data in the beginning of remap_buf. The leftover data is already
+ * remapped, so it's not part of the input, it's part of the output. */
+
+ have_leftover = r->remap_buf_contains_leftover_data;
+ r->remap_buf_contains_leftover_data = FALSE;
- if (!r->map_required || !input->length)
+ if (!have_leftover && (!r->map_required || input->length <= 0))
return input;
+ else if (input->length <= 0)
+ return &r->remap_buf;
in_n_samples = (unsigned) (input->length / r->w_sz);
- n_frames = in_n_samples / r->i_ss.channels;
- out_n_samples = n_frames * r->o_ss.channels;
+ in_n_frames = out_n_frames = in_n_samples / r->i_ss.channels;
- r->remap_buf.index = 0;
- r->remap_buf.length = r->w_sz * out_n_samples;
+ if (have_leftover) {
+ leftover_length = r->remap_buf.length;
+ out_n_frames += leftover_length / (r->w_sz * r->o_ss.channels);
+ }
+
+ out_n_samples = out_n_frames * r->o_ss.channels;
+ r->remap_buf.length = out_n_samples * r->w_sz;
+
+ if (have_leftover) {
+ if (r->remap_buf_size < r->remap_buf.length) {
+ pa_memblock *new_block = pa_memblock_new(r->mempool, r->remap_buf.length);
+
+ src = pa_memblock_acquire(r->remap_buf.memblock);
+ dst = pa_memblock_acquire(new_block);
+ memcpy(dst, src, leftover_length);
+ pa_memblock_release(r->remap_buf.memblock);
+ pa_memblock_release(new_block);
- if (!r->remap_buf.memblock || r->remap_buf_samples < out_n_samples) {
- if (r->remap_buf.memblock)
pa_memblock_unref(r->remap_buf.memblock);
+ r->remap_buf.memblock = new_block;
+ r->remap_buf_size = r->remap_buf.length;
+ }
- r->remap_buf_samples = out_n_samples;
- r->remap_buf.memblock = pa_memblock_new(r->mempool, r->remap_buf.length);
+ } else {
+ if (!r->remap_buf.memblock || r->remap_buf_size < r->remap_buf.length) {
+ if (r->remap_buf.memblock)
+ pa_memblock_unref(r->remap_buf.memblock);
+
+ r->remap_buf_size = r->remap_buf.length;
+ r->remap_buf.memblock = pa_memblock_new(r->mempool, r->remap_buf.length);
+ }
}
- src = ((uint8_t*) pa_memblock_acquire(input->memblock) + input->index);
- dst = pa_memblock_acquire(r->remap_buf.memblock);
+ src = (uint8_t *) pa_memblock_acquire(input->memblock) + input->index;
+ dst = (uint8_t *) pa_memblock_acquire(r->remap_buf.memblock) + leftover_length;
+
+ if (r->map_required) {
+ pa_remap_t *remap = &r->remap;
- remap = &r->remap;
+ pa_assert(remap->do_remap);
+ remap->do_remap(remap, dst, src, in_n_frames);
- pa_assert(remap->do_remap);
- remap->do_remap(remap, dst, src, n_frames);
+ } else
+ memcpy(dst, src, input->length);
pa_memblock_release(input->memblock);
pa_memblock_release(r->remap_buf.memblock);
@@ -1243,6 +1299,32 @@ void pa_resampler_run(pa_resampler *r, const pa_memchunk *in, pa_memchunk *out)
pa_memchunk_reset(out);
}
+static void save_leftover(pa_resampler *r, void *buf, size_t len) {
+ void *dst;
+
+ pa_assert(r);
+ pa_assert(buf);
+ pa_assert(len > 0);
+
+ /* Store the leftover to remap_buf. */
+
+ r->remap_buf.length = len;
+
+ if (!r->remap_buf.memblock || r->remap_buf_size < r->remap_buf.length) {
+ if (r->remap_buf.memblock)
+ pa_memblock_unref(r->remap_buf.memblock);
+
+ r->remap_buf_size = r->remap_buf.length;
+ r->remap_buf.memblock = pa_memblock_new(r->mempool, r->remap_buf.length);
+ }
+
+ dst = pa_memblock_acquire(r->remap_buf.memblock);
+ memcpy(dst, buf, r->remap_buf.length);
+ pa_memblock_release(r->remap_buf.memblock);
+
+ r->remap_buf_contains_leftover_data = TRUE;
+}
+
/*** libsamplerate based implementation ***/
#ifdef HAVE_LIBSAMPLERATE
@@ -1266,7 +1348,13 @@ static void libsamplerate_resample(pa_resampler *r, const pa_memchunk *input, un
data.end_of_input = 0;
pa_assert_se(src_process(r->src.state, &data) == 0);
- pa_assert((unsigned) data.input_frames_used == in_n_frames);
+
+ if (data.input_frames_used < in_n_frames) {
+ void *leftover_data = data.data_in + data.input_frames_used * r->o_ss.channels;
+ size_t leftover_length = (in_n_frames - data.input_frames_used) * sizeof(float) * r->o_ss.channels;
+
+ save_leftover(r, leftover_data, leftover_length);
+ }
pa_memblock_release(input->memblock);
pa_memblock_release(output->memblock);
@@ -1327,10 +1415,16 @@ static void speex_resample_float(pa_resampler *r, const pa_memchunk *input, unsi
pa_assert_se(speex_resampler_process_interleaved_float(r->speex.state, in, &inf, out, &outf) == 0);
+ if (inf < in_n_frames) {
+ void *leftover_data = in + inf * r->o_ss.channels;
+ size_t leftover_length = (in_n_frames - inf) * sizeof(float) * r->o_ss.channels;
+
+ save_leftover(r, leftover_data, leftover_length);
+ }
+
pa_memblock_release(input->memblock);
pa_memblock_release(output->memblock);
- pa_assert(inf == in_n_frames);
*out_n_frames = outf;
}
@@ -1348,10 +1442,16 @@ static void speex_resample_int(pa_resampler *r, const pa_memchunk *input, unsign
pa_assert_se(speex_resampler_process_interleaved_int(r->speex.state, in, &inf, out, &outf) == 0);
+ if (inf < in_n_frames) {
+ void *leftover_data = in + inf * r->o_ss.channels;
+ size_t leftover_length = (in_n_frames - inf) * sizeof(int16_t) * r->o_ss.channels;
+
+ save_leftover(r, leftover_data, leftover_length);
+ }
+
pa_memblock_release(input->memblock);
pa_memblock_release(output->memblock);
- pa_assert(inf == in_n_frames);
*out_n_frames = outf;
}
@@ -1595,6 +1695,7 @@ static int peaks_init(pa_resampler*r) {
static void ffmpeg_resample(pa_resampler *r, const pa_memchunk *input, unsigned in_n_frames, pa_memchunk *output, unsigned *out_n_frames) {
unsigned used_frames = 0, c;
+ int previous_consumed_frames = -1;
pa_assert(r);
pa_assert(input);
@@ -1606,25 +1707,14 @@ static void ffmpeg_resample(pa_resampler *r, const pa_memchunk *input, unsigned
pa_memblock *b, *w;
int16_t *p, *t, *k, *q, *s;
int consumed_frames;
- unsigned in, l;
/* Allocate a new block */
b = pa_memblock_new(r->mempool, r->ffmpeg.buf[c].length + in_n_frames * sizeof(int16_t));
p = pa_memblock_acquire(b);
- /* Copy the remaining data into it */
- l = (unsigned) r->ffmpeg.buf[c].length;
- if (r->ffmpeg.buf[c].memblock) {
- t = (int16_t*) ((uint8_t*) pa_memblock_acquire(r->ffmpeg.buf[c].memblock) + r->ffmpeg.buf[c].index);
- memcpy(p, t, l);
- pa_memblock_release(r->ffmpeg.buf[c].memblock);
- pa_memblock_unref(r->ffmpeg.buf[c].memblock);
- pa_memchunk_reset(&r->ffmpeg.buf[c]);
- }
-
- /* Now append the new data, splitting up channels */
+ /* Now copy the input data, splitting up channels */
t = ((int16_t*) ((uint8_t*) pa_memblock_acquire(input->memblock) + input->index)) + c;
- k = (int16_t*) ((uint8_t*) p + l);
+ k = (int16_t*) ((uint8_t*) p);
for (u = 0; u < in_n_frames; u++) {
*k = *t;
t += r->o_ss.channels;
@@ -1632,9 +1722,6 @@ static void ffmpeg_resample(pa_resampler *r, const pa_memchunk *input, unsigned
}
pa_memblock_release(input->memblock);
- /* Calculate the resulting number of frames */
- in = (unsigned) in_n_frames + l / (unsigned) sizeof(int16_t);
-
/* Allocate buffer for the result */
w = pa_memblock_new(r->mempool, *out_n_frames * sizeof(int16_t));
q = pa_memblock_acquire(w);
@@ -1643,19 +1730,15 @@ static void ffmpeg_resample(pa_resampler *r, const pa_memchunk *input, unsigned
used_frames = (unsigned) av_resample(r->ffmpeg.state,
q, p,
&consumed_frames,
- (int) in, (int) *out_n_frames,
+ (int) in_n_frames, (int) *out_n_frames,
c >= (unsigned) (r->o_ss.channels-1));
pa_memblock_release(b);
+ pa_memblock_unref(b);
- /* Now store the remaining samples away */
- pa_assert(consumed_frames <= (int) in);
- if (consumed_frames < (int) in) {
- r->ffmpeg.buf[c].memblock = b;
- r->ffmpeg.buf[c].index = (size_t) consumed_frames * sizeof(int16_t);
- r->ffmpeg.buf[c].length = (size_t) (in - (unsigned) consumed_frames) * sizeof(int16_t);
- } else
- pa_memblock_unref(b);
+ pa_assert(consumed_frames <= (int) in_n_frames);
+ pa_assert(previous_consumed_frames == -1 || consumed_frames == previous_consumed_frames);
+ previous_consumed_frames = consumed_frames;
/* And place the results in the output buffer */
s = (short*) ((uint8_t*) pa_memblock_acquire(output->memblock) + output->index) + c;
@@ -1669,6 +1752,14 @@ static void ffmpeg_resample(pa_resampler *r, const pa_memchunk *input, unsigned
pa_memblock_unref(w);
}
+ if (previous_consumed_frames < (int) in_n_frames) {
+ void *leftover_data = (int16_t *) ((uint8_t *) pa_memblock_acquire(input->memblock) + output->index) + previous_consumed_frames * r->o_ss.channels;
+ size_t leftover_length = (in_n_frames - previous_consumed_frames) * r->o_ss.channels * sizeof(int16_t);
+
+ save_leftover(r, leftover_data, leftover_length);
+ pa_memblock_release(input->memblock);
+ }
+
*out_n_frames = used_frames;
}
--
1.7.10
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