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bluetooth: Handle fragmented faststream frames

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Incoming frames can span multiple packets, add support for this.

Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/628>
This commit is contained in:
Igor V. Kovalenko 2021-09-08 21:03:54 +03:00
parent 697a1a309a
commit 76e01b25f5
1 changed files with 61 additions and 13 deletions
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74
src/modules/bluetooth/a2dp-codec-sbc.c
View file

@ -39,6 +39,8 @@
#define SBC_BITPOOL_DEC_STEP 5
#define SBC_BITPOOL_INC_STEP 1
#define SBC_SYNCWORD 0x9C
struct sbc_info {
sbc_t sbc; /* Codec data */
size_t codesize, frame_length; /* SBC Codesize, frame_length. We simply cache those values here */
@ -54,6 +56,11 @@ struct sbc_info {
uint8_t nr_blocks;
uint8_t nr_subbands;
/* Size of SBC frame fragment left over from previous decoding iteration */
size_t frame_fragment_size;
/* Maximum SBC frame size is 512 bytes when SBC compression ratio > 1 */
uint8_t frame_fragment[512];
};
static bool can_be_supported(bool for_encoding) {
@ -936,6 +943,9 @@ static int reset(void *codec_info) {
struct sbc_info *sbc_info = (struct sbc_info *) codec_info;
int ret;
/* forget last saved frame fragment */
sbc_info->frame_fragment_size = 0;
ret = sbc_reinit(&sbc_info->sbc, 0);
if (ret != 0) {
pa_log_error("SBC reinitialization failed: %d", ret);
@ -1279,27 +1289,60 @@ static size_t decode_buffer_faststream(void *codec_info, const uint8_t *input_bu
.rate = 16000U
};
uint8_t decode_buffer[4096];
uint8_t frame_buffer[4096];
p = input_buffer;
to_decode = input_size;
/* append input buffer to fragment left from previous decode call */
if (sbc_info->frame_fragment_size) {
if (sbc_info->frame_fragment_size + to_decode > sizeof(frame_buffer)) {
pa_log_debug("FastStream SBC input (saved + incoming) size %lu larger than buffer size %lu, input truncated to fit",
sbc_info->frame_fragment_size + to_decode, sizeof(frame_buffer));
to_decode = sizeof(frame_buffer) - sbc_info->frame_fragment_size;
}
memcpy(frame_buffer, sbc_info->frame_fragment, sbc_info->frame_fragment_size);
memcpy(frame_buffer + sbc_info->frame_fragment_size, input_buffer, to_decode);
to_decode += sbc_info->frame_fragment_size;
p = frame_buffer;
/* clear saved fragment */
sbc_info->frame_fragment_size = 0;
} else
p = input_buffer;
d = output_buffer;
to_write = output_size;
while (PA_LIKELY(to_decode > 0 && to_write > 0)) {
size_t written;
size_t written = 0;
ssize_t decoded;
/* skip to SBC sync word before attempting decode */
if (*p != SBC_SYNCWORD) {
++p;
--to_decode;
continue;
}
decoded = sbc_decode(&sbc_info->sbc,
p, to_decode,
decode_buffer, sizeof(decode_buffer),
&written);
if (PA_UNLIKELY(decoded <= 0)) {
/* sbc_decode returns -1 if input too short,
* break from loop to save this frame fragment for next decode iteration */
if (decoded == -1) {
pa_log_debug("FastStream SBC decoding error (%li) input %lu is too short", (long) decoded, to_decode);
break;
}
/* otherwise failed to decode frame, skip to next SBC sync word */
pa_log_error("FastStream SBC decoding error (%li)", (long) decoded);
decoded = PA_MIN(sbc_info->frame_length, to_decode);
written = PA_MIN(sbc_info->codesize, to_write);
pa_silence_memory(decode_buffer, written, &decoded_sample_spec);
decoded = 1;
} else {
/* Reset codesize and frame_length to values found by decoder */
sbc_info->codesize = sbc_get_codesize(&sbc_info->sbc);
@ -1325,14 +1368,7 @@ static size_t decode_buffer_faststream(void *codec_info, const uint8_t *input_bu
memcpy(d, decode_buffer, written);
}
if ((sbc_info->frame_length & 1) && decoded < to_decode) {
++decoded;
++sbc_info->frame_length;
}
pa_assert_fp((size_t) decoded <= to_decode);
pa_assert_fp((size_t) decoded == PA_MIN(sbc_info->frame_length, to_decode));
pa_assert_fp((size_t) written <= to_write);
p += decoded;
@ -1342,7 +1378,19 @@ static size_t decode_buffer_faststream(void *codec_info, const uint8_t *input_bu
to_write -= written;
}
/* XXX eat remainder, may need to fix this if input frames are split across packets */
if (to_decode) {
if (to_decode > sizeof(sbc_info->frame_fragment)) {
pa_log_debug("FastStream remaining SBC fragment size %lu larger than buffer size %lu, remainder truncated to fit",
to_decode, sizeof(sbc_info->frame_fragment));
p += to_decode - sizeof(sbc_info->frame_fragment);
to_decode = sizeof(sbc_info->frame_fragment);
}
pa_log_debug("FastStream saving SBC fragment size %lu for next decoding iteration", to_decode);
memcpy(sbc_info->frame_fragment, p, to_decode);
sbc_info->frame_fragment_size = to_decode;
}
*processed = input_size;
return d - output_buffer;