1 /*
2 * Copyright (c) 2020 Marton Balint
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include "avcodec.h"
22 #include "bsf_internal.h"
23 #include "libavutil/avassert.h"
24 #include "libavutil/opt.h"
25
26 typedef struct PCMContext {
27 const AVClass *class;
28
29 int nb_out_samples;
30 int pad;
31 AVRational frame_rate;
32
33 AVPacket *in_pkt;
34 AVPacket *out_pkt;
35 int sample_size;
36 int64_t n;
37 } PCMContext;
38
init(AVBSFContext * ctx)39 static int init(AVBSFContext *ctx)
40 {
41 PCMContext *s = ctx->priv_data;
42 AVRational sr = av_make_q(ctx->par_in->sample_rate, 1);
43 int64_t min_samples;
44
45 if (ctx->par_in->channels <= 0 || ctx->par_in->sample_rate <= 0)
46 return AVERROR(EINVAL);
47
48 ctx->time_base_out = av_inv_q(sr);
49 s->sample_size = ctx->par_in->channels * av_get_bits_per_sample(ctx->par_in->codec_id) / 8;
50
51 if (s->frame_rate.num) {
52 min_samples = av_rescale_q_rnd(1, sr, s->frame_rate, AV_ROUND_DOWN);
53 } else {
54 min_samples = s->nb_out_samples;
55 }
56 if (min_samples <= 0 || min_samples > INT_MAX / s->sample_size - 1)
57 return AVERROR(EINVAL);
58
59 s->in_pkt = av_packet_alloc();
60 s->out_pkt = av_packet_alloc();
61 if (!s->in_pkt || !s->out_pkt)
62 return AVERROR(ENOMEM);
63
64 return 0;
65 }
66
uninit(AVBSFContext * ctx)67 static void uninit(AVBSFContext *ctx)
68 {
69 PCMContext *s = ctx->priv_data;
70 av_packet_free(&s->in_pkt);
71 av_packet_free(&s->out_pkt);
72 }
73
flush(AVBSFContext * ctx)74 static void flush(AVBSFContext *ctx)
75 {
76 PCMContext *s = ctx->priv_data;
77 av_packet_unref(s->in_pkt);
78 av_packet_unref(s->out_pkt);
79 s->n = 0;
80 }
81
send_packet(PCMContext * s,int nb_samples,AVPacket * pkt)82 static int send_packet(PCMContext *s, int nb_samples, AVPacket *pkt)
83 {
84 pkt->duration = nb_samples;
85 s->n++;
86 return 0;
87 }
88
drain_packet(AVPacket * pkt,int drain_data,int drain_samples)89 static void drain_packet(AVPacket *pkt, int drain_data, int drain_samples)
90 {
91 pkt->size -= drain_data;
92 pkt->data += drain_data;
93 if (pkt->dts != AV_NOPTS_VALUE)
94 pkt->dts += drain_samples;
95 if (pkt->pts != AV_NOPTS_VALUE)
96 pkt->pts += drain_samples;
97 }
98
get_next_nb_samples(AVBSFContext * ctx)99 static int get_next_nb_samples(AVBSFContext *ctx)
100 {
101 PCMContext *s = ctx->priv_data;
102 if (s->frame_rate.num) {
103 AVRational sr = av_make_q(ctx->par_in->sample_rate, 1);
104 return av_rescale_q(s->n + 1, sr, s->frame_rate) - av_rescale_q(s->n, sr, s->frame_rate);
105 } else {
106 return s->nb_out_samples;
107 }
108 }
109
rechunk_filter(AVBSFContext * ctx,AVPacket * pkt)110 static int rechunk_filter(AVBSFContext *ctx, AVPacket *pkt)
111 {
112 PCMContext *s = ctx->priv_data;
113 int nb_samples = get_next_nb_samples(ctx);
114 int data_size = nb_samples * s->sample_size;
115 int ret;
116
117 do {
118 if (s->in_pkt->size) {
119 if (s->out_pkt->size || s->in_pkt->size < data_size) {
120 int drain = FFMIN(s->in_pkt->size, data_size - s->out_pkt->size);
121 if (!s->out_pkt->size) {
122 ret = av_new_packet(s->out_pkt, data_size);
123 if (ret < 0)
124 return ret;
125 ret = av_packet_copy_props(s->out_pkt, s->in_pkt);
126 if (ret < 0) {
127 av_packet_unref(s->out_pkt);
128 return ret;
129 }
130 s->out_pkt->size = 0;
131 }
132 memcpy(s->out_pkt->data + s->out_pkt->size, s->in_pkt->data, drain);
133 s->out_pkt->size += drain;
134 drain_packet(s->in_pkt, drain, drain / s->sample_size);
135 if (!s->in_pkt->size)
136 av_packet_unref(s->in_pkt);
137 if (s->out_pkt->size == data_size) {
138 av_packet_move_ref(pkt, s->out_pkt);
139 return send_packet(s, nb_samples, pkt);
140 }
141 } else if (s->in_pkt->size > data_size) {
142 ret = av_packet_ref(pkt, s->in_pkt);
143 if (ret < 0)
144 return ret;
145 pkt->size = data_size;
146 drain_packet(s->in_pkt, data_size, nb_samples);
147 return send_packet(s, nb_samples, pkt);
148 } else {
149 av_assert0(s->in_pkt->size == data_size);
150 av_packet_move_ref(pkt, s->in_pkt);
151 return send_packet(s, nb_samples, pkt);
152 }
153 }
154
155 ret = ff_bsf_get_packet_ref(ctx, s->in_pkt);
156 if (ret == AVERROR_EOF && s->out_pkt->size) {
157 if (s->pad) {
158 memset(s->out_pkt->data + s->out_pkt->size, 0, data_size - s->out_pkt->size);
159 s->out_pkt->size = data_size;
160 } else {
161 nb_samples = s->out_pkt->size / s->sample_size;
162 }
163 av_packet_move_ref(pkt, s->out_pkt);
164 return send_packet(s, nb_samples, pkt);
165 }
166 if (ret >= 0)
167 av_packet_rescale_ts(s->in_pkt, ctx->time_base_in, ctx->time_base_out);
168 } while (ret >= 0);
169
170 return ret;
171 }
172
173 #define OFFSET(x) offsetof(PCMContext, x)
174 #define FLAGS (AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_BSF_PARAM)
175 static const AVOption options[] = {
176 { "nb_out_samples", "set the number of per-packet output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, FLAGS },
177 { "n", "set the number of per-packet output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, FLAGS },
178 { "pad", "pad last packet with zeros", OFFSET(pad), AV_OPT_TYPE_BOOL, {.i64=1} , 0, 1, FLAGS },
179 { "p", "pad last packet with zeros", OFFSET(pad), AV_OPT_TYPE_BOOL, {.i64=1} , 0, 1, FLAGS },
180 { "frame_rate", "set number of packets per second", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, FLAGS },
181 { "r", "set number of packets per second", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, FLAGS },
182 { NULL },
183 };
184
185 static const AVClass pcm_rechunk_class = {
186 .class_name = "pcm_rechunk_bsf",
187 .item_name = av_default_item_name,
188 .option = options,
189 .version = LIBAVUTIL_VERSION_INT,
190 };
191
192 static const enum AVCodecID codec_ids[] = {
193 AV_CODEC_ID_PCM_S16LE,
194 AV_CODEC_ID_PCM_S16BE,
195 AV_CODEC_ID_PCM_S8,
196 AV_CODEC_ID_PCM_S32LE,
197 AV_CODEC_ID_PCM_S32BE,
198 AV_CODEC_ID_PCM_S24LE,
199 AV_CODEC_ID_PCM_S24BE,
200 AV_CODEC_ID_PCM_F32BE,
201 AV_CODEC_ID_PCM_F32LE,
202 AV_CODEC_ID_PCM_F64BE,
203 AV_CODEC_ID_PCM_F64LE,
204 AV_CODEC_ID_PCM_S64LE,
205 AV_CODEC_ID_PCM_S64BE,
206 AV_CODEC_ID_PCM_F16LE,
207 AV_CODEC_ID_PCM_F24LE,
208 AV_CODEC_ID_NONE,
209 };
210
211 const AVBitStreamFilter ff_pcm_rechunk_bsf = {
212 .name = "pcm_rechunk",
213 .priv_data_size = sizeof(PCMContext),
214 .priv_class = &pcm_rechunk_class,
215 .filter = rechunk_filter,
216 .init = init,
217 .flush = flush,
218 .close = uninit,
219 .codec_ids = codec_ids,
220 };
221