[FFmpeg-devel] [PATCH] avcodec/binkaudio: add support for >2 channels dct codec
Paul B Mahol
onemda at gmail.com
Fri Mar 18 17:21:44 EET 2022
On 3/18/22, Andreas Rheinhardt <andreas.rheinhardt at outlook.com> wrote:
> Paul B Mahol:
>> As presented in .binka files.
>>
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> ---
>> libavcodec/binkaudio.c | 50 +++++++++++++++++++++++++++---------------
>> 1 file changed, 32 insertions(+), 18 deletions(-)
>>
>> diff --git a/libavcodec/binkaudio.c b/libavcodec/binkaudio.c
>> index b4ff15beeb..54b7e22854 100644
>> --- a/libavcodec/binkaudio.c
>> +++ b/libavcodec/binkaudio.c
>> @@ -51,13 +51,14 @@ typedef struct BinkAudioContext {
>> int version_b; ///< Bink version 'b'
>> int first;
>> int channels;
>> + int ch_offset;
>> int frame_len; ///< transform size (samples)
>> int overlap_len; ///< overlap size (samples)
>> int block_size;
>> int num_bands;
>> float root;
>> unsigned int bands[26];
>> - float previous[MAX_CHANNELS][BINK_BLOCK_MAX_SIZE / 16]; ///< coeffs
>> from previous audio block
>> + float previous[6][BINK_BLOCK_MAX_SIZE / 16]; ///< coeffs from
>> previous audio block
>> float quant_table[96];
>> AVPacket *pkt;
>> union {
>> @@ -74,6 +75,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
>> int sample_rate_half;
>> int i, ret;
>> int frame_len_bits;
>> + int max_channels = avctx->codec->id == AV_CODEC_ID_BINKAUDIO_RDFT ?
>> MAX_CHANNELS : 6;
>
> If you allow up to six channels, then MAX_CHANNELS (i.e. two) needs to
> be renamed.
>
>> int channels = avctx->ch_layout.nb_channels;
>>
>> /* determine frame length */
>> @@ -85,7 +87,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
>> frame_len_bits = 11;
>> }
>>
>> - if (channels < 1 || channels > MAX_CHANNELS) {
>> + if (channels < 1 || channels > max_channels) {
>> av_log(avctx, AV_LOG_ERROR, "invalid number of channels: %d\n",
>> channels);
>> return AVERROR_INVALIDDATA;
>> }
>> @@ -110,7 +112,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
>>
>> s->frame_len = 1 << frame_len_bits;
>> s->overlap_len = s->frame_len / 16;
>> - s->block_size = (s->frame_len - s->overlap_len) * s->channels;
>> + s->block_size = (s->frame_len - s->overlap_len) *
>> FFMIN(MAX_CHANNELS, s->channels);
>> sample_rate_half = (sample_rate + 1LL) / 2;
>> if (avctx->codec->id == AV_CODEC_ID_BINKAUDIO_RDFT)
>> s->root = 2.0 / (sqrt(s->frame_len) * 32768.0);
>> @@ -166,7 +168,8 @@ static const uint8_t rle_length_tab[16] = {
>> * @param[out] out Output buffer (must contain s->block_size elements)
>> * @return 0 on success, negative error code on failure
>> */
>> -static int decode_block(BinkAudioContext *s, float **out, int use_dct)
>> +static int decode_block(BinkAudioContext *s, float **out, int use_dct,
>> + int channels, int ch_offset)
>> {
>> int ch, i, j, k;
>> float q, quant[25];
>> @@ -176,8 +179,8 @@ static int decode_block(BinkAudioContext *s, float
>> **out, int use_dct)
>> if (use_dct)
>> skip_bits(gb, 2);
>>
>> - for (ch = 0; ch < s->channels; ch++) {
>> - FFTSample *coeffs = out[ch];
>> + for (ch = 0; ch < channels; ch++) {
>> + FFTSample *coeffs = out[ch + ch_offset];
>>
>> if (s->version_b) {
>> if (get_bits_left(gb) < 64)
>> @@ -252,17 +255,17 @@ static int decode_block(BinkAudioContext *s, float
>> **out, int use_dct)
>> s->trans.rdft.rdft_calc(&s->trans.rdft, coeffs);
>> }
>>
>> - for (ch = 0; ch < s->channels; ch++) {
>> + for (ch = 0; ch < channels; ch++) {
>> int j;
>> - int count = s->overlap_len * s->channels;
>> + int count = s->overlap_len * channels;
>> if (!s->first) {
>> j = ch;
>> - for (i = 0; i < s->overlap_len; i++, j += s->channels)
>> - out[ch][i] = (s->previous[ch][i] * (count - j) +
>> - out[ch][i] * j) / count;
>> + for (i = 0; i < s->overlap_len; i++, j += channels)
>> + out[ch + ch_offset][i] = (s->previous[ch + ch_offset][i]
>> * (count - j) +
>> + out[ch + ch_offset][i] *
>> j) / count;
>> }
>> - memcpy(s->previous[ch], &out[ch][s->frame_len - s->overlap_len],
>> - s->overlap_len * sizeof(*s->previous[ch]));
>> + memcpy(s->previous[ch + ch_offset], &out[ch +
>> ch_offset][s->frame_len - s->overlap_len],
>> + s->overlap_len * sizeof(*s->previous[ch + ch_offset]));
>> }
>>
>> s->first = 0;
>> @@ -293,6 +296,7 @@ static int binkaudio_receive_frame(AVCodecContext
>> *avctx, AVFrame *frame)
>> GetBitContext *gb = &s->gb;
>> int ret;
>>
>> +again:
>> if (!s->pkt->data) {
>> ret = ff_decode_get_packet(avctx, s->pkt);
>> if (ret < 0)
>> @@ -313,22 +317,31 @@ static int binkaudio_receive_frame(AVCodecContext
>> *avctx, AVFrame *frame)
>> }
>>
>> /* get output buffer */
>> - frame->nb_samples = s->frame_len;
>> - if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
>> - return ret;
>> + if (s->ch_offset == 0) {
>> + frame->nb_samples = s->frame_len;
>> + if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
>> + return ret;
>> + }
>>
>> if (decode_block(s, (float **)frame->extended_data,
>> - avctx->codec->id == AV_CODEC_ID_BINKAUDIO_DCT)) {
>> + avctx->codec->id == AV_CODEC_ID_BINKAUDIO_DCT,
>> + FFMIN(MAX_CHANNELS, s->channels), s->ch_offset)) {
>> av_log(avctx, AV_LOG_ERROR, "Incomplete packet\n");
>> return AVERROR_INVALIDDATA;
>> }
>> + s->ch_offset += MAX_CHANNELS;
>> get_bits_align32(gb);
>> if (!get_bits_left(gb)) {
>> memset(gb, 0, sizeof(*gb));
>> av_packet_unref(s->pkt);
>> }
>> + if (s->ch_offset >= s->channels) {
>> + s->ch_offset = 0;
>> + } else {
>> + goto again;
>> + }
>
> Is it really intended that the data for one multi-channel frame is
> divided into several input packets?
You are missing big picture here, >2 files have channels in different
packets interleaved.
Something like in XMA. (And nothing signals how are they interleaved.
so its worse than in XMA) So it is working fine. I just need another
look for possible regressions and security implications. Renaming
MAX_CHANNELS is not useful as that is not property of both codecs.
>
>>
>> - frame->nb_samples = s->block_size / avctx->ch_layout.nb_channels;
>> + frame->nb_samples = s->block_size /
>> FFMIN(avctx->ch_layout.nb_channels, MAX_CHANNELS);
>>
>> return 0;
>> fail:
>> @@ -343,6 +356,7 @@ static void decode_flush(AVCodecContext *avctx)
>> /* s->pkt coincides with avctx->internal->in_pkt
>> * and is unreferenced generically when flushing. */
>> s->first = 1;
>> + s->ch_offset = 0;
>> }
>>
>> const AVCodec ff_binkaudio_rdft_decoder = {
>
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