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libtheoraenc.c
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1 /*
2  * Copyright (c) 2006 Paul Richards <paul.richards@gmail.com>
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 /**
22  * @file
23  * @brief Theora encoder using libtheora.
24  * @author Paul Richards <paul.richards@gmail.com>
25  *
26  * A lot of this is copy / paste from other output codecs in
27  * libavcodec or pure guesswork (or both).
28  *
29  * I have used t_ prefixes on variables which are libtheora types
30  * and o_ prefixes on variables which are libogg types.
31  */
32 
33 /* FFmpeg includes */
34 #include "libavutil/common.h"
35 #include "libavutil/intreadwrite.h"
36 #include "libavutil/pixdesc.h"
37 #include "libavutil/log.h"
38 #include "libavutil/base64.h"
39 #include "avcodec.h"
40 #include "internal.h"
41 
42 /* libtheora includes */
43 #include <theora/theoraenc.h>
44 
45 typedef struct TheoraContext {
46  th_enc_ctx *t_state;
50  int uv_hshift;
51  int uv_vshift;
54 
55 /** Concatenate an ogg_packet into the extradata. */
56 static int concatenate_packet(unsigned int* offset,
57  AVCodecContext* avc_context,
58  const ogg_packet* packet)
59 {
60  const char* message = NULL;
61  int newsize = avc_context->extradata_size + 2 + packet->bytes;
62  int err = AVERROR_INVALIDDATA;
63 
64  if (packet->bytes < 0) {
65  message = "ogg_packet has negative size";
66  } else if (packet->bytes > 0xffff) {
67  message = "ogg_packet is larger than 65535 bytes";
68  } else if (newsize < avc_context->extradata_size) {
69  message = "extradata_size would overflow";
70  } else {
71  if ((err = av_reallocp(&avc_context->extradata, newsize)) < 0) {
72  avc_context->extradata_size = 0;
73  message = "av_realloc failed";
74  }
75  }
76  if (message) {
77  av_log(avc_context, AV_LOG_ERROR, "concatenate_packet failed: %s\n", message);
78  return err;
79  }
80 
81  avc_context->extradata_size = newsize;
82  AV_WB16(avc_context->extradata + (*offset), packet->bytes);
83  *offset += 2;
84  memcpy(avc_context->extradata + (*offset), packet->packet, packet->bytes);
85  (*offset) += packet->bytes;
86  return 0;
87 }
88 
89 static int get_stats(AVCodecContext *avctx, int eos)
90 {
91 #ifdef TH_ENCCTL_2PASS_OUT
92  TheoraContext *h = avctx->priv_data;
93  uint8_t *buf;
94  int bytes;
95 
96  bytes = th_encode_ctl(h->t_state, TH_ENCCTL_2PASS_OUT, &buf, sizeof(buf));
97  if (bytes < 0) {
98  av_log(avctx, AV_LOG_ERROR, "Error getting first pass stats\n");
99  return AVERROR_EXTERNAL;
100  }
101  if (!eos) {
102  h->stats = av_fast_realloc(h->stats, &h->stats_size,
103  h->stats_offset + bytes);
104  memcpy(h->stats + h->stats_offset, buf, bytes);
105  h->stats_offset += bytes;
106  } else {
107  int b64_size = AV_BASE64_SIZE(h->stats_offset);
108  // libtheora generates a summary header at the end
109  memcpy(h->stats, buf, bytes);
110  avctx->stats_out = av_malloc(b64_size);
111  av_base64_encode(avctx->stats_out, b64_size, h->stats, h->stats_offset);
112  }
113  return 0;
114 #else
115  av_log(avctx, AV_LOG_ERROR, "libtheora too old to support 2pass\n");
116  return AVERROR(ENOSUP);
117 #endif
118 }
119 
120 // libtheora won't read the entire buffer we give it at once, so we have to
121 // repeatedly submit it...
122 static int submit_stats(AVCodecContext *avctx)
123 {
124 #ifdef TH_ENCCTL_2PASS_IN
125  TheoraContext *h = avctx->priv_data;
126  int bytes;
127  if (!h->stats) {
128  if (!avctx->stats_in) {
129  av_log(avctx, AV_LOG_ERROR, "No statsfile for second pass\n");
130  return AVERROR(EINVAL);
131  }
132  h->stats_size = strlen(avctx->stats_in) * 3/4;
133  h->stats = av_malloc(h->stats_size);
134  h->stats_size = av_base64_decode(h->stats, avctx->stats_in, h->stats_size);
135  }
136  while (h->stats_size - h->stats_offset > 0) {
137  bytes = th_encode_ctl(h->t_state, TH_ENCCTL_2PASS_IN,
138  h->stats + h->stats_offset,
139  h->stats_size - h->stats_offset);
140  if (bytes < 0) {
141  av_log(avctx, AV_LOG_ERROR, "Error submitting stats\n");
142  return AVERROR_EXTERNAL;
143  }
144  if (!bytes)
145  return 0;
146  h->stats_offset += bytes;
147  }
148  return 0;
149 #else
150  av_log(avctx, AV_LOG_ERROR, "libtheora too old to support 2pass\n");
151  return AVERROR(ENOSUP);
152 #endif
153 }
154 
155 static av_cold int encode_init(AVCodecContext* avc_context)
156 {
157  th_info t_info;
158  th_comment t_comment;
159  ogg_packet o_packet;
160  unsigned int offset;
161  TheoraContext *h = avc_context->priv_data;
162  uint32_t gop_size = avc_context->gop_size;
163  int ret;
164 
165  /* Set up the theora_info struct */
166  th_info_init(&t_info);
167  t_info.frame_width = FFALIGN(avc_context->width, 16);
168  t_info.frame_height = FFALIGN(avc_context->height, 16);
169  t_info.pic_width = avc_context->width;
170  t_info.pic_height = avc_context->height;
171  t_info.pic_x = 0;
172  t_info.pic_y = 0;
173  /* Swap numerator and denominator as time_base in AVCodecContext gives the
174  * time period between frames, but theora_info needs the framerate. */
175  t_info.fps_numerator = avc_context->time_base.den;
176  t_info.fps_denominator = avc_context->time_base.num;
177  if (avc_context->sample_aspect_ratio.num) {
178  t_info.aspect_numerator = avc_context->sample_aspect_ratio.num;
179  t_info.aspect_denominator = avc_context->sample_aspect_ratio.den;
180  } else {
181  t_info.aspect_numerator = 1;
182  t_info.aspect_denominator = 1;
183  }
184 
185  if (avc_context->color_primaries == AVCOL_PRI_BT470M)
186  t_info.colorspace = TH_CS_ITU_REC_470M;
187  else if (avc_context->color_primaries == AVCOL_PRI_BT470BG)
188  t_info.colorspace = TH_CS_ITU_REC_470BG;
189  else
190  t_info.colorspace = TH_CS_UNSPECIFIED;
191 
192  if (avc_context->pix_fmt == AV_PIX_FMT_YUV420P)
193  t_info.pixel_fmt = TH_PF_420;
194  else if (avc_context->pix_fmt == AV_PIX_FMT_YUV422P)
195  t_info.pixel_fmt = TH_PF_422;
196  else if (avc_context->pix_fmt == AV_PIX_FMT_YUV444P)
197  t_info.pixel_fmt = TH_PF_444;
198  else {
199  av_log(avc_context, AV_LOG_ERROR, "Unsupported pix_fmt\n");
200  return AVERROR(EINVAL);
201  }
203 
204  if (avc_context->flags & CODEC_FLAG_QSCALE) {
205  /* Clip global_quality in QP units to the [0 - 10] range
206  to be consistent with the libvorbis implementation.
207  Theora accepts a quality parameter which is an int value in
208  the [0 - 63] range.
209  */
210  t_info.quality = av_clipf(avc_context->global_quality / (float)FF_QP2LAMBDA, 0, 10) * 6.3;
211  t_info.target_bitrate = 0;
212  } else {
213  t_info.target_bitrate = avc_context->bit_rate;
214  t_info.quality = 0;
215  }
216 
217  /* Now initialise libtheora */
218  h->t_state = th_encode_alloc(&t_info);
219  if (!h->t_state) {
220  av_log(avc_context, AV_LOG_ERROR, "theora_encode_init failed\n");
221  return AVERROR_EXTERNAL;
222  }
223 
224  h->keyframe_mask = (1 << t_info.keyframe_granule_shift) - 1;
225  /* Clear up theora_info struct */
226  th_info_clear(&t_info);
227 
228  if (th_encode_ctl(h->t_state, TH_ENCCTL_SET_KEYFRAME_FREQUENCY_FORCE,
229  &gop_size, sizeof(gop_size))) {
230  av_log(avc_context, AV_LOG_ERROR, "Error setting GOP size\n");
231  return AVERROR_EXTERNAL;
232  }
233 
234  // need to enable 2 pass (via TH_ENCCTL_2PASS_) before encoding headers
235  if (avc_context->flags & CODEC_FLAG_PASS1) {
236  if ((ret = get_stats(avc_context, 0)) < 0)
237  return ret;
238  } else if (avc_context->flags & CODEC_FLAG_PASS2) {
239  if ((ret = submit_stats(avc_context)) < 0)
240  return ret;
241  }
242 
243  /*
244  Output first header packet consisting of theora
245  header, comment, and tables.
246 
247  Each one is prefixed with a 16bit size, then they
248  are concatenated together into libavcodec's extradata.
249  */
250  offset = 0;
251 
252  /* Headers */
253  th_comment_init(&t_comment);
254 
255  while (th_encode_flushheader(h->t_state, &t_comment, &o_packet))
256  if ((ret = concatenate_packet(&offset, avc_context, &o_packet)) < 0)
257  return ret;
258 
259  th_comment_clear(&t_comment);
260 
261  /* Set up the output AVFrame */
262  avc_context->coded_frame = av_frame_alloc();
263 
264  return 0;
265 }
266 
267 static int encode_frame(AVCodecContext* avc_context, AVPacket *pkt,
268  const AVFrame *frame, int *got_packet)
269 {
270  th_ycbcr_buffer t_yuv_buffer;
271  TheoraContext *h = avc_context->priv_data;
272  ogg_packet o_packet;
273  int result, i, ret;
274 
275  // EOS, finish and get 1st pass stats if applicable
276  if (!frame) {
277  th_encode_packetout(h->t_state, 1, &o_packet);
278  if (avc_context->flags & CODEC_FLAG_PASS1)
279  if ((ret = get_stats(avc_context, 1)) < 0)
280  return ret;
281  return 0;
282  }
283 
284  /* Copy planes to the theora yuv_buffer */
285  for (i = 0; i < 3; i++) {
286  t_yuv_buffer[i].width = FFALIGN(avc_context->width, 16) >> (i && h->uv_hshift);
287  t_yuv_buffer[i].height = FFALIGN(avc_context->height, 16) >> (i && h->uv_vshift);
288  t_yuv_buffer[i].stride = frame->linesize[i];
289  t_yuv_buffer[i].data = frame->data[i];
290  }
291 
292  if (avc_context->flags & CODEC_FLAG_PASS2)
293  if ((ret = submit_stats(avc_context)) < 0)
294  return ret;
295 
296  /* Now call into theora_encode_YUVin */
297  result = th_encode_ycbcr_in(h->t_state, t_yuv_buffer);
298  if (result) {
299  const char* message;
300  switch (result) {
301  case -1:
302  message = "differing frame sizes";
303  break;
304  case TH_EINVAL:
305  message = "encoder is not ready or is finished";
306  break;
307  default:
308  message = "unknown reason";
309  break;
310  }
311  av_log(avc_context, AV_LOG_ERROR, "theora_encode_YUVin failed (%s) [%d]\n", message, result);
312  return AVERROR_EXTERNAL;
313  }
314 
315  if (avc_context->flags & CODEC_FLAG_PASS1)
316  if ((ret = get_stats(avc_context, 0)) < 0)
317  return ret;
318 
319  /* Pick up returned ogg_packet */
320  result = th_encode_packetout(h->t_state, 0, &o_packet);
321  switch (result) {
322  case 0:
323  /* No packet is ready */
324  return 0;
325  case 1:
326  /* Success, we have a packet */
327  break;
328  default:
329  av_log(avc_context, AV_LOG_ERROR, "theora_encode_packetout failed [%d]\n", result);
330  return AVERROR_EXTERNAL;
331  }
332 
333  /* Copy ogg_packet content out to buffer */
334  if ((ret = ff_alloc_packet2(avc_context, pkt, o_packet.bytes)) < 0)
335  return ret;
336  memcpy(pkt->data, o_packet.packet, o_packet.bytes);
337 
338  // HACK: assumes no encoder delay, this is true until libtheora becomes
339  // multithreaded (which will be disabled unless explicitly requested)
340  pkt->pts = pkt->dts = frame->pts;
341  avc_context->coded_frame->key_frame = !(o_packet.granulepos & h->keyframe_mask);
342  if (avc_context->coded_frame->key_frame)
343  pkt->flags |= AV_PKT_FLAG_KEY;
344  *got_packet = 1;
345 
346  return 0;
347 }
348 
349 static av_cold int encode_close(AVCodecContext* avc_context)
350 {
351  TheoraContext *h = avc_context->priv_data;
352 
353  th_encode_free(h->t_state);
354  av_freep(&h->stats);
355  av_freep(&avc_context->coded_frame);
356  av_freep(&avc_context->stats_out);
357  av_freep(&avc_context->extradata);
358  avc_context->extradata_size = 0;
359 
360  return 0;
361 }
362 
363 /** AVCodec struct exposed to libavcodec */
365  .name = "libtheora",
366  .long_name = NULL_IF_CONFIG_SMALL("libtheora Theora"),
367  .type = AVMEDIA_TYPE_VIDEO,
368  .id = AV_CODEC_ID_THEORA,
369  .priv_data_size = sizeof(TheoraContext),
370  .init = encode_init,
371  .close = encode_close,
372  .encode2 = encode_frame,
373  .capabilities = CODEC_CAP_DELAY, // needed to get the statsfile summary
374  .pix_fmts = (const enum AVPixelFormat[]){
376  },
377 };